SAILING
Bob Copeland
© 2002 R C Copeland
VivaYo152@aol.com. All rights reserved
OPERATING THE BOAT
SAFETY FIRST!
Check the boat, rig, engine, and sails before operating. Be sure gear is stowed
Be sure no loaded line can become a “slingshot” if a block breaks
Install the lifebuoy, with MOB pole and light. Discuss how to use it
Check fire extinguishers and flares. Be sure the first aid kit is stocked
Be extremely careful of fire while underway. Better to cook at anchor
Use a waterproof apron while cooking
On the water, sun burns fast; use sunscreen
Drink plenty of water to avoid dehydration and reduce tiring
Shivering is the first sign of hypothermia
Fatigue, cold, and seasickness lead to dangerous mistakes
Usually occur when circumstances can become dangerous
If they start, plan the quickest route to safety
Check drinking water, battery charge, fuel, and engine operation
Be sure cooling thruhull is open and oil is full
In close maneuvering under sail, have the motor running for backup
Always wear a life vest at night, and safety harness if wind is strong
In waves, always wear a safety harness on the foredeck
In broaching conditions, all crew should wear safety harnesses
In a broach, release sheets – not halyards
Yell a warning to others if a large wave or gust approaches
In large waves, keep all hatches closed and fastened
Stay away from lee shores in heavy air or waves!
If a squall line is approaching, get reefed and a smaller jib
Smooth seas and rising tides are the only time for shallow water
Never step on a sail, especially if wet
Don’t let lines slide thru your hands: they cut like glass
Keep line ends out of the way and free to run, usually below
Wear gloves and shoes. Test for grip on a wet deck
Be extremely careful operating winches – they can remove fingers
Check the weather report before going offshore
Look out for fog if humidity high and temperature dropping
Be sure charts are available and nav equipment is working, if needed
Plan the trip, including courses, nav marks, lights, tides, and dangers
Get a position fix at least hourly, and check for potential dangers
Keep a watch, and keep watching, at all times
Never assume anyone, especially a stinkpot, will yield right-of-way
When anchoring, have 5:1 scope, and back down to be sure it’s set
Check weather report, tides, and currents for potential problems
VHF radio Mayday, on Ch. 16: State “Mayday”, Boat name and type, Position, and Problem
LEAVING SHIP
Gas off, Cocks closed, Head locked, Breakers off [except bilge pump], Rigging lines secure, Backstay off, Sails stowed, Mooring lines secure
COMPETITION FACTORS – Prepare and Execute
BOATSPEED
Hull Bottom Standing Rig Sails Instruments
Keel and rudder Running Rig Hardware
6 kn. = 10 min./mile. 1% speed change = 6 sec./mile = 1’ rating
PERSONAL
Physical Condition Observation Patience
Mental Condition Anticipation Safety
Concentration Analysis
STRATEGY
Race Instructions Course Wind Current Start
TACTICS
Clear Air Crossing Current
Wind Shifts Covering Mark Roundings
CREW [Primary responsibilities – may be assigned]
Helm: Drive, Mainsheet, Traveler, Backstay
Port and St’bd Trimmers: Jib sheet, Vang, Cunningham, Outhaul,
Spinnaker sheet, Afterguy, Pole lift, Foreguy
Foredeck: Rig spinnaker, Jibe pole, Clear halyards/lines, Lookout,
Tactics, Call waves
Mastman: [Same as Foredeck on end-for-end jibe] Hoist/lower
sails, Raise inner pole, Trip pole, Assist foredeck, Barberhauls, Leech lines, Pre-start info, Time start
KNOTS
Bowline, Sheetbend, Square knot, 2 half hitches, Anchor bend, Clove hitch, Belaying hitch
SAIL TRIM UPWIND
Sight up mast while beating to assure dead straight both tacks
Max backstay: Sight up forestay while tighten in medium wind
At max when forestay gets no straighter
Mark controls, e.g. pen marks on lines, and keep records
Setup order:
Backstay, babystay, jib halyard, jib blocks, jibsheet, barberhauls
Main halyard, cunningham, outhaul, traveler, vang, mainsheet
Leech lines
Check, continually, in following order [trim is never perfect]:
Twist, trim angle, draft position/amount, even slot, helm balance
All adjustments affect others, esp. backstay
If boat won’t go it’s usually too little twist – ease sheets
Never get the main more twisted than the jib
As speed builds, can trim in to point, if desired
Don’t cleat sheets, work them!
Forward third of sail’s shape is most important, esp. curve of luff
Flat entry to point; rounded for speed or power
Light-to-moderate air: Sails hoisted with some luff wrinkles
Full draft with a little twist
A little flatter, and slightly more twist, in very light air
As wind increases, begin tightening controls
Draft flatter, more forward, less twist
Keep as much power as the boat will take
Some weather helm helps keel work to windward
Compromise: Power has to be reduced to point high
With GPS and a mark, VMG for best trim can be checked
Heavy air: Tighten luffs to create some overbend wrinkles
Max sail area possible – overpower. Winner usually does
Move sheet leads [jib lead and traveler] out as wind increases
Increase twist as wind increases [sheets eased and jib car aft]
Balance the sails and boat to reduce rudder angle
JIB TRIM UPWIND
Backstay: Set 6 – 10% draft, depending on wind strength
Flatter draft in flat water, fuller in a chop for power
Jib slightly fuller than main, slightly more forward
Halyard: Set draft 35 – 45% aft [30 – 40 for fractional rig]
As wind increases, tighten halyard to move draft further forward
Flatter luff entry in flat water [tighten backstay], to point
Rounder in a chop [tighter halyard], for power
Car: Fore/aft location set for even luff break on both tacks
May require different location on each side
Move lead forward slightly in light air, ease halyard
Move lead aft and/or out in heavier air, tighten halyard
About 8 degrees off center to point, 10 for speed or power
[10 degree = 21” out @ 10’ aft of tack]
Low luff in sail is bad; move car aft or ease sheet
May be wind sheer [will be opposite on each tack]
Jibsheet: Sets twist as well as trim angle
Keep telltales flying evenly and continuously back in light air
As wind increases, inner up more and more, esp. upper ones
If steering groove too narrow, ease backstay or tighten jib halyard
MAIN TRIM UPWIND
Backstay, babystay, and outhaul: Set 6-10% draft
Runners flatten jib while holding draft in main
Babystay does opposite
Cunningham: Set draft 45-55% aft [40-50 for fractional rig]
Traveler: Sets trim angle. Slight-to-heavy backwind at low luff Depending on wind strength and jib overlap
Top telltale slightly stalled [More to point, flowing for power]
Mainsheet: Sets twist. Boom approximately on center
In slightly to point, out slightly for power, out more to depower
Set top batten parallel boom [In slightly to point, out for power]
Set slot to match jib. Less twist to point, more for speed
In heavy air, sail the main on the battens and highly twisted
Vang: Set to automatically allow slight twist as sheet eased to tack
SHIFTING GEARS UPWIND
Must be able to work gears – fast! – while hiked on the rail
Crew must do immediately, usually without being told
Involve sheets, traveler, cunningham, backstay, vang
Power: Slightly ease sheets and backstay for speed or acceleration
Tighten Cunningham and jib halyard. Ease outhaul slightly
Round entries, open leeches, moderate twist for speed and power
Point: Tighten backstay, sheets, outhaul. Ease halyard/cunn.
Flatten sail entries, close leaches, reduce twist
Must build speed before pointing, e.g. on tacks
Otherwise sails and keel stall and boat goes slow and sideways
To build speed, set all controls for pointing
Except slightly ease sheets and backstay to accelerate
Then trim sheets, b’stay together to tighten leeches [slot even]
Depower: In gusts, ease sheets, tighten backstay quickly, then retrim
Sail on the back half of the sails – keep them working thru gusts
Must sail aggressively – overpower with control, boat driving
Controls on hard! Esp. backstay and halyards/cunningham
Backstay, running backs, babystay must coordinate for bend
Traveler and jib lead out – much twist, upper sails luffing in gusts
Unreefed main, smaller jib better than opposite
BOAT HANDLING UPWIND
Watch [crew helps]: Wind on water, waves, jib telltales, headstay sag [immediately shows windspeed change], main backwind and leech telltales, compass [for wind shifts], other boats
Keep crew close together, weight on high or low side for balance
Tack fast, at speed, on wave crests
Look 90 degrees for reference, or use compass
Tack, ease main, don’t over turn, build speed, point up, trim in
Have to build speed before boat can point
Roll tack: Hike hard near head to wind, release jib, shift fast to other side, hike hard as sheet in [lean out and extend arms and legs]
In gusty wind, be on port tack in lulls, on starboard in gusts
In light air keep boat moving, avoid tacking except on shifts
Sudden change in velocity often indicates a shift
Use rolltack and pumping to accelerate boat [like “flapping”]
If stuck in irons, push boom out opposite desired tack
Power up and foot, especially in a chop
Try to keep all jib telltales, both sides, flying straight aft
In heavy air, ease sheets, foot off slightly, keep boat driving hard
Cross-sheet jib; set up barberhauls
Work sheets and backstay, and sail aggressively
If overpowered and stall, speed goes down fast
Speed gives stability [keel more effective], reduces leeway
Head up slightly in puffs, off in lulls to sail constant heel angle
Balance tiller on fingertips, ventilate rudder by short, fast jerks
Keep weather jib telltales flying up; main luffing except battens
Foot off even more when pounding. “S” thru waves
Work sheets to use gusts to accelerate, not leeway and stalling
Steer “up the waves up, down the waves down”, in rhythm
SAIL TRIM OFFWIND
Don’t overvang the main
Pole generally square to wind, clew heights even, luff vertical
If spinnaker breaks high, pole is too high, and vice versa
On a reach: Lower pole, barberhaul clew down if needed
Heavy air: Pole more forward and down – choke sail down
Set up barberhaul on sheet
Light air: Pole more aft to project sail into wind
Use telltales @ 1/3, 2/3 down, 1-2’ in from spinnaker leeches
Triradial works as high as 50 degrees apparent in moderate wind
Double head rig [genoa and staysail] fastest @ 40-50 degrees
On reaches use staysail with spinnaker
BOATHANDLING OFFWIND
As rounding weather mark, get spinnaker up and drawing fast
Crew weight forward in light air, aft in heavy air, close together
Steer down in puffs, up in lulls. Build speed, then head down
In light air, steer an “S” with wind shifts to maximize speed
Steer to help spinnaker trimmer – don’t steer straight
Better to set sails, steer to windex, than constant trimming
Keep the forward edge of the sail luffing slightly at all times
Watch compass and masthead fly and jibe on major lifts
Theoretical best angles: Light air-95 degrees, mod-135, hvy-170
Not sure true! GPS VMG will verify
To surf: Keep boat on its feet, reach up for speed, steer down as stern lifts, pump guy and sheets once each wave to start
Heavy air
Use jib for helm balance and to avoid spinnaker wrap on forestay
Sheet led outboard to the rail, eased for lots of twist
Overtrim pole [back] on reach, undertrim on run for control
Ease pole, sheet in hard, to stop death roll near dead downwind
Speed creates stability: the faster the better
Depower order: Vang, pole, mainsheet, spinnaker sheet
Work vang constantly to depower if broaching threatens
Put some of crew on lee rail if lee helm exists
Rule for round-up (broach), round-down (chinese jibe):
“Wet side eases”: Ease low side, crank in high side
In broach, dump main, ease spinnaker sheet
In chinese jibe, sheet main in and pump it, ease pole
Retrim sails as boat steers back to course
SPINNAKER HANDLING
[Practice these and other procedures in this outline by picturing them in your mind. “Virtual sailing”]
Hoisting Checklist:
Correct spinnaker. Packed right. Sheets and guys led correctly
Halyards clear. Set foreguy so pole can raise to just over lifelines
Decide round set [pole raised before mark], or jibe set
Jib and sheet free to jibe over pole if a jibe-set
Hoisting Procedure:
If a round-set, have pole set just over lifelines, ready for hoist
If a jibe-set, have pole’s forward end on deck
Hoist to just over lifelines as jib crosses
Hoist spinnaker quickly but smoothly
Keep pole down and forward initially, above lifeline, aft forestay
Pole back, square with wind, at ¾ hoist. Fully up at full hoist
Foreguy must be eased for both
Most crews sheet in hard immediately as sail is hoisted
Better to delay, to avoid stalling. Sheet in after pole is back
Heavier air: Pole down and back, sheet hard to avoid hourglass
If sail twists, lower halyard slightly, pull foot and leeches
Trim sheet completely only at full hoist. Avoid stalling the sail
Drop and lash down the jib [except heavy air leave it up]
Ease controls for downwind: Backstay, outhaul, cunningham, halyards
Jibing Checklist:
Remove mainsail preventer, if installed
If dip-pole jibe, lead new guy/sheet correctly. New guy to bow
Pole inboard end ready to raise
Unhook babystay
Jibing Procedure [End-for-end]:
Head boat dead downwind, and trim spinnaker square to wind
Foreguy may have to be eased for pole to come back
Bring mainsail onto centerline
Unclip pole from mast and clip it to new afterguy
Unclip pole from old afterguy and push it out. Clip butt to mast
Ease out the mainsail on new jibe
Trim while heading up to new course
Jibing Procedure [Dip-pole]:
Head boat dead downwind, and square spinnaker to wind
Bring mainsail onto centerline
Raise pole butt to band, trip the pole off the sail
Lower the outboard end of pole, swing through the foretriangle
Connect new afterguy. Swing pole out
Ease out the mainsail on new jibe
Lower the pole butt and top up the pole
Pull the new guy aft to square pole to wind. Trim the sheet
Ease old afterguy and sheet
Trim while heading up to new course
Take-Down Checklist:
Decide on a weather or leeward takedown
To weather can keep it inside the jib, on the boat
Assure spinnaker halyard, sheet, and guy free to run
Hoist jib and preset backstay, outhaul, cunningham
Takedown Procedure:
Ease pole forward and keep sheet trimmed while heading up
Trim main and jib for new course while heading up
Take hold of afterguy or sheet, ready to haul in
Let off halyard as fast as gathered in
Gather spinnaker in and stuff it below
Repack spinnaker and rerun lines
RACING TACTICS
GENERAL
Know the rules! Few know more than the basics
Don’t let them avoid responsibility by ignorance
Get the race instructions; pencil course marks on the boat
Races are lost by error, more than they are won by brilliance
Every opportunity for gain is an opportunity for loss, and v.v.
Watch out for potential major mistakes and advantages
Cover ahead and to leeward, loose or tight, esp late in a leg
Ahead to leeward gains in both a lift or header
Don’t get trapped on the layline
Fake a tack or jibe, or do quick double one, to break a cover
Find marks long before the layline, and plan the rounding
Get an inside overlap at 2 lengths to control mark roundings
Avoid boats with right-of-way; watch for luffing or broaching
Steer without preoccupation, e.g. watching crew. Concentrate!
Stay focused on the race, strategy, and boatspeed
Stay out of luffing matches
Must be close to cross to lee bow; can slam dunk if cross
Be constantly aware of wind and current strength around course
Important at all time, absolutely critical in light air
In light air tack seldom, jibe often, don’t chase wind patches
Be patient and stay focused, continuously check other boats
Wind direction may differ around the course
Sail toward side of course, toward shore, if there is more wind
Sail point-to-point in a channel; short-tack off points for a lift
STARTING
Prior to start, determine:
P and S tack headings, oscillations, time to run line [pencil those on boat], favored end and side, current affect
Favored end: Lifted tack to line. F. tack: Lifted tack to mark
Develop a standard plan, with alternatives. Always follow it
B C
A
D
¯[Wind]
pin* * com. boat
C D
A B D
A C A B D
¬ Position @ 1.25 x time to run line before start gun Distance from pin = 2/3 start line length
Distance boat travels = 100’ per min per knot
10’/sec@6 kn, approx. 1.7’/sec/kn.
Starboard tack starts:
A – Pin end, left side favored. Tack onto starboard 10 sec. before half time expired
B – Right end, left side favored. Must yield while on port
Port tack starts:
C – Pin end, right side favored. Should cross fleet if wind to left
Tack onto port 10 sec. before half time expired
D – Right end, right side favored. Cross or duck starboard boats
Watch out for committee boat anchor line!
Critical at start: Clear air, full speed, going right way or can tack
Consider: Where want to be 5 minutes after start?
Observe starting plan of others, e.g. barging
Must get a decent start, excellent start usually not imperative
With current down line toward pin or to leeward, barge!
Skippers who usually barge are incompetent
Or think everyone else is. Tack to leeward, and force them up
After start, continue to check: wind shifts, relative positions of other boats, wind shifts shown by other boats
In light air, head to side of course, otherwise work up the middle
Must sail to a persistent shift – or will end on “great circle route”
SAILING TO WEATHER
Persistent shift is deadly – avoid lifted tack if it may occur
[Persistent: Wind shifts and does not return, e.g. Sequim Bay]
May be actual shift, sail into different wind, change in current
Stay near rhumb line, away from layline, and watch other boats
Tack to expected shift, but only beyond others, short of layline
But do not sail toward expected 40+ degree shift
Becomes 1-leg beat, and boat is beyond layline
In oscillating wind, stay in phase
Tack when wind goes over 5 degrees past median, over 20 sec
When in doubt, don’t tack
If boats on same tack point higher, tack
Conversely, if boats on opposite tack point lower, tack
SAILING OFFWIND
Downwind, if persistent shift expected, sail lifted jibe initially
Otherwise sail headed jibe, and jibe on lifts
As important as tacking on headers upwind – and opposite
On reach, if persistent lift expected, sail low initially
If major header expected, sail high so can come back down
Sail low at beginning of reach unless wind increasing
Work down lower than competition for better angle later
PASSING
Blanket zone is a cone 5 boat lengths downwind
Backwind is 1 length to weather, 3-5 lengths back along course
Both cause header and turbulence
Less critical in turbulent airflow, and shifts give passing options
To pass, position just to leeward or well to windward
A boat ahead can sail up (“luff”) but cannot move down if within 2 lengths of boat trying to pass downwind
Use shifts in windspeed and apparent wind to try to drive thru
If more than 2 lengths downwind when overlap established can move up and luff even if don’t pass clear ahead
Fake tacks or gybes, or do quick double ones
Be patient and watch for mistakes
Race form
[BOAT NAME]
Race___________ Date/Time____________ Finish ____________
Crew__________________________________________________
Start line bearings______/______Ranges_____________________
Marks/Headings_________________________________________
Tide heights/Time _______________________________________
Current: Slack @_______Max @________Dir______ Speed_____
Slack @_______Max @________Dir______ Speed_____
Differences around course _______________________________
Shoreline effects _______________________________________
Depth contours ________________________________________
Wind: Source _________________ Expect continue? ___________
Speed_____ Dir_____ Stable/unstable______________________
Steady/Oscillating/Shifting? _____________________________
Range _______________________________________________
Shoreline effects_______________________________________
Differences around course_______________________________
Beat headings: S ________ P ________ S ________ P _________
Time to run line _______ sec. Fav. end _______ Fav. side _______
Start: _________________________________________________
Boats to watch: _________________________________________
Alerts: ________________________________________________
RACING RULES, PART 2 – WHEN BOATS MEET
The rules of Part 2 apply between boats that are sailing in or near the racing area and intend to race, are racing or have been racing.
Section A – Right of Way
A boat has right of way when another boat is required to keep clear of her. However, some rules in Section 5 B and C limit the actions of a right-of-way boat.
10 ON OPPOSITE TACKS
When boats are on opposite tacks, a port-tack boat shall keep clear of a starboard-tack boat.
11 ON THE SAME TACK, OVERLAPPED
When boats are on the same tack and overlapped, a windward boat shall keep clear of a leeward boat.
12 ON THE SAME TACK, NOT OVERLAPPED
When boats are on the same tack and not overlapped, a boat clear astern shall keep clear of a boat clear ahead.
13 WHILE TACKING
After a boat passes head to wind, she shall keep clear of other boats until she is on a close-hauled course. During that time rules 10, 11, and 12 do not apply. If two boats are subject to this rule at the same time, the one on the other’s port side shall keep clear.
Section B – General Limitations
14 AVOIDING CONTACT
A boat shall avoid contact with another boat if reasonably possible. However, a right-of-way boat or one entitled to room
(a) need not act to avoid contact until it is clear that the other boat is not keeping clear or giving room, and
(b) shall not be penalized unless there is contact that causes damage.
I5 ACQUIRING RIGHT OF WAY
When a boat acquires right of way, she shall initially give the other boat room to keep clear, unless she acquires right of way because of the other boat’s actions.
16 CHANGING COURSE
When a right-of-way boat changes course, she shall give the other boat room to keep clear.
17 ON THE SAME TACK; PROPER COURSE
17.1 A boat that establishes a leeward overlap from clear astern within two of her hull lengths of a windward boat shall not sail above her proper course during that overlap while the boats are less than that distance apart, unless as a result she becomes clear astern.
17.2 Except on a beat to windward, while a boat is less than two of her hull lengths from a leeward boat or a boat clear astern steering a course to leeward of her, she shall not sail below her proper course unless she gybes.
Section C – At Marks and Obstructions
When a Section C rule applies, the rules in Sections A and B continue to apply unless the Section C rule modifies them or states that they do not apply.
18 PASSING MARKS AND OBSTRUCTIONS
18.1 When this Rule Applies
Rule 18 applies at a mark or obstruction to be left on the same side when boats are about to pass it until they have passed it. However, it does not apply
(a) at a starting mark or its anchor line surrounded by navigable water from the time the boats are approaching them to start until they have passed them, or
(b) between boats on opposite tacks when they are on a beat to windward or when the proper course for one of them to pass the mark or obstruction is to tack.
18.2 Giving Room; Keeping Clear
(a) When boats are overlapped before one of them reaches the two-length zone, if the outside boat has right of way she shall give the inside boat room to pass the mark or obstruction, or if the inside boat has right of way the outside boat shall keep clear. If they are still overlapped when one of them reaches the two-length zone, the outside boat’s obligation continues even if the overlap is broken later. This rule does not apply if the outside boat is unable to give room when the overlap begins.
(b) If a boat is clear ahead when she reaches the two-length zone, the boat clear astern shall keep clear even if an overlap is established later. Rule 10 does not apply. If the boat clear ahead tacks, rule 13 applies and this rule no longer does.
(c) If there is reasonable doubt that a boat established or broke an overlap in time, it shall be presumed that she did not.
18.3 Tacking
If two boats were on opposite tacks and one of them tacked within the two-length zone to pass a mark or obstruction, rule 18.2 does not apply. The boat that tacked
(a) shall not cause the other boat to sail above close-hauled to avoid her or prevent the other boat from passing the mark or obstruction, and
(b) shall keep clear if the other boat becomes overlapped inside her, in which case rule 15 does not apply.
18.4 Gybing
When rule 18.2(a) applies and an inside overlapped right-of-way boat must gybe at the mark or obstruction to sail her proper course, she shall pass no farther from the mark or obstruction than needed to sail that course.
I8.5 Passing a Continuing Obstruction
At a continuing obstruction, rule 18.2 is modified so that while boats are passing the obstruction an outside boat’s obligation ends if the overlap is broken, and a boat clear astern may establish an inside overlap provided there is room at that time to pass between the other boat and the obstruction. If she does so, her obligation under rule 18.2(b) ends.
19 ROOM TO TACK AT AN OBSTRUCTION
19.1 When safety requires a close-hauled boat to make a substantial course change to avoid an obstruction and she intends to tack, but cannot tack and avoid another boat on the same tack, she shall hail for room to do so. Before tacking she shall give the hailed boat time to respond. The hailed boat shall either
(a) tack as soon as possible, in which case the hailing boat shall also tack as soon as possible, or
(b) immediately reply `You tack’, in which case the hailing boat shall immediately tack and the hailed boat shall give room, and rules 10 and 13 do not apply.
19.2 Rule 19.1 does not apply at a starting mark or its anchor line surrounded by navigable water from the time boats are approaching them to start until they have passed them, or at a mark that the hailed boat can fetch. When rule 19.1 applies, rule 18 does not.
RACING FLAGS
Start Sequence: Yellow: 10 min Blue: 5 min. Red: 1st start
Come within hail: L flag. One minute rule: Yellow with black dot
Postponement: Red and white vertical stripes; 2 horn blasts
Boat over early: White square with blue cross; 1 blast
General recall: Blue border around yellow triangle; 2 blasts
Shorten course: White square with blue center; 2 blasts
Twice around: Red, white, and blue vertical stripes
Reverse course: Red with yellow cross
Abandon race: Black and white checkered; 3 blasts
Protest flag: Red
WINDS
SOURCES OF WIND
Convection causes all wind, by uneven heating/cooling of the earth
Pressure and buoyancy of the air changes, and it rises or falls
Hi pushes air outward, as air sinks in center evaporating clouds
Lo is opposite: air in center rises, clouds form from condensation
Land heats/cools faster. Dry air heats/cools faster
Winds may be general, over a large area, or local
Four causes of convection:
1. Thermal: Air rises as heated [hills may assist]
Lower temp aloft causes lighter air to rise, heavier to fall
Brings down wind from above or sides to replace
May be in small cells, or cover huge geographic area
2. Orographic lift: Air mass passes over elevation changes
3. Front: Boundary between 2 air masses [1 colder]
One air mass displaces the other
Warm front passes over cold; cold under warm
Occluded front is worst weather [cold catches warm]
Fronts travel west to east or northeast
4. Convergence zone: Collision of 2 opposing winds
Wind is vertical, therefore light and variable at surface
May be heavy rain or thunderstorms
Types of winds:
Gradient winds: Air moves from hi to lo pressure
Coriollus force: Caused by earth’s rotation
Wind goes clockwise around hi; counter-c. around lo
Facing wind, lo is on right, hi is on left
Strongest winds are S.E. of the lo center [since it moves east]
Seabreeze: Land heats, rising thermal pulls air in off cooler water
Winds stable overall; but may be unstable in lower elevations
Stability increases during the day. Thermal dies as day cools
Wind strength varies 10 – 25kn
Landbreeze: Land cools in evening, air flows downhill
Tradewinds: Only in subtropics
AIR MASS STABILITY
Air masses more likely stable in winter: less heating of the land
Except when cold fronts pass, lifting warmer air
Stable air mass: Air mass cools at less than adiabatic lapse rate
[Standard rate of cooling is 12 degrees/1000’ altitude increase]
Maintains same air pressure at all altitudes: no rise or fall
Higher temp aloft stops lower air from rising – an inversion
They often form as earth cools from radiation at night
Stability causes lower and steadier velocity and direction in wind
Flows around obstructions like water does [channeling]
May have gusts downwind of obstructions as eddies form
Lifts off surface before a large obstruction it can’t flow around
Stratus clouds, often fog forms; any rain is usually a steady drizzle
Unstable air mass: Rising air causes vertical mixing, gusty winds
Wind tends to go over obstructions, with limited channeling
Winds veer, i.e. clockwise, in gusts, as higher winds descend
Pulled down to replace rising air currents
Cumulous clouds likely; any rain is usually showers, thunderstorms
Turbulent air won’t attach to sails [Frustrating. Flatten them more]
WIND STRENGTH
BEAUFORT WIND SPEED SCALE
Force Speed Description Max Waves
2 5k Light breeze [wind barely felt on face] Ripples
3 10k Gentle breeze [Occasional white crests] 2’
4 15k Mod. breeze [Frequent white crests] 4’
5 20k Fresh breeze [Sea foamy, some spray] 6’
6 25k Strong breeze [Rig whistles] 10’
7 30k Near gale [Spindrift, waves break] 14’
8 40k Gale [Foam blown in streaks] 18’
9 45k Strong gale [Spray affects visibility] 20’
Wind force: Wind pressure increases as the square of the speed
Calms and light winds result from:
Small pressure gradient, stable air mass, inversion, no surface heating, hi pressure, back side of circular flow
Strong winds result from:
Large gradient, channeling, unstable air mass, surface heating, rapid buildup of a hi [over 1030mb], lo under 980 mb, front side of circular flow
Abrupt change in speed or direction results from:
Front passage, sea breeze starts or dies, inversion forms or breaks [often in the morning], thunderstorm, unstable air mass
FACTORS AFFECTING EXISTING WINDS
Geographic features
Cause persistent shifts, channeling, velocity changes, gustiness
Instability in the air mass
Cold front, hot sun with few clouds [esp. p.m.], no inversion
Frontal passage [usually 3-day process. Faster in winter]
Fronts move over the ocean at 5 – 60 kn
Slowest in summer; slower over land
Hi passes N: Wind goes from NW to N/NE to E/SE
Hi passes S: Wind goes from W/SW to S
Lo passes N: Wind goes from SE to SW to NW
Usual in Puget Sound
Lo passes S: Wind goes from SE/E to NE
Currents
Affects direction and velocity of the apparent wind
Equal, opposite the current
Sailing into a current change causes a persistent shift
Anticipate it if possible
Vector calculates shift [see “Piloting”]
WIND SHIFTS
Stable air: Relatively steady, non-shifting wind
e.g. Seabreeze starts offshore midmorning after inversion breaks
Builds and veers till midafternoon, backs as it dies. Inversion forms
Unstable air: Oscillations as upper winds come down
May be random or patterned, typically 10 – 20 min. in light air
As fast as 2 – 3 min. in heavy air; gusts are usually veered
Patterns usually fairly predictable in speed and direction
The higher the speed difference, the faster and farther the change
The dominance of one wind over the other may reverse
Wind slants may be visible in bands across the water
They move right to left. Be on starboard in the gusts
Persistent shift: Any time a new wind direction prevails
It is the most critical determinant of race outcome
May arrive progressively or instantaneously
Caused by seabreeze, front passage, break in inversion
The longer the leg, the more likely one will occur
Suspect whenever wind moves past previous oscillations
Or if a continuing change in velocity, or original wind dies
Watch clouds, smoke, swell, boats, etc for direction change
Oscillations may occur during a progressive persistent shift
If so, once it reaches max it will probably shift back some
May occur at specific points around course, e.g. channeling
Different winds in different areas of the course is common
Changes in topography, e.g. a point, make a shift certain
Changes in current cause an apparent wind shift
Stable wind crossing shore will channel or lift before shore
Unstable will turn more perpendicular
Downburst: Catspaw to thunderstorm
Size of cloud shows size; anvil shows t’storm weakening
Wind radiates out from center: Sail a reach around center
Inversions – layer of warmer air at higher altitude
Usually form at night in hi as land cools
They stop the mixing of windy upper and calm lower air
Calm or light, backed winds develop at surface
Cause haze and stagnant air; may last days
As they break, faster veered wind comes down
Break is not instant, gusts and oscillations give warning
Wind shear: May cause different wind at deck and masthead!
Results from layering of 2 different winds
Requires severe twist one tack, reverse twist on other! Frustrating
Sheet to best compromise [sail “lifted” wind each tack?]
CURRENT
Current called by the direction it flows [opposite wind]
Study shoreline and depths [faster where deep or passes point]
Flow reverses inshore first when tide changes
Fastest current outside a bend, or off a point
Eddies and speed changes shown by flotsam line and tide rips
May be just off a point as well as behind it
Wind against current creates chop; if with current, a smooth
Change of tide may cause a wind change – watch for it
It certainly will change the apparent wind
Try to “lee-bow”: current on lee bow pushes upwind
In constant current, there is no “lee-bow” advantage
If current changes during race, lee-bow strategy is critical
Use ranges, buoys, float to gauge current – look behind!
PUGET SOUND CLIMATE
Position of Pacific hi [1025mb] most important factor
S in winter, N in summer off the coast
Alters typical weather if it does not follow the norm
E.g. if it stays north in winter, drought occurs
Dec. – Feb: Permanent lo in Gulf of Alaska sends continual storms
Pacific hi is south and does not block these
Mar. – May: Hi starts north and begins blocking storms
June – Aug: Well-developed hi
Alternates warm sunny periods with cloudy marine air
Cloudy days are cool, but usually have sun breaks
Sun often brings seabreeze
West seabreeze in Strait, north seabreeze in Sound
Increases if lo in E Wa and hot sun in Centralia
Hi in E Wa can bring hot east winds
Sep. – Nov: Hi moves south and storms begin to break thru
Fog common, especially in the Strait
If hi stays late, have beautiful indian summer
PUGET SOUND WINDS
Convergence zone: N.W. wind splits around Olympics
Reconverges on sound from N and S
Usually forms at Everett and moves S to Tacoma
Gradient winds: Substantially altered by channeling from:
Strait, Sound, Hood Canal, Olympics, Cascades
Elevation changes, headlands, etc. affect flow
Affect speed and direction of the wind
Wind tends to follow the shape of the sound
Frontal passage: Pressure difference determines wind speed
The faster barometer falls, faster storm comes, stronger it is
Wind usually shifts SE to SW in Sound at passage
May shift 90 degrees in one minute as front goes thru
May shift E to W in Strait
Superstorms, below 970 mb, form quickly from far S
Seabreeze: Typical in summer when sunny
Becomes gusty as strength increases, due to topography
Strait may have W winds to 25 kn, gusting 40. May be fog
Strongest winds S.Vancouver Is., 7 p.m. to midnight
Expect if a lo in E Wa
Seabreeze moves S down Sound, fills on W side first
Winds N if Centralia hot, NW if lo over E Wa
Wind dies at sundown unless a lo over E Wa
Arctic front: Forms in winter with hi over Canada, lo in Cal
Frigid air flows S, may exceed 25 kn, and last 2 weeks
Winds typically NE to E
Heavy snow if wet marine air displaced
Hi pressure wind: N to NW wind, may blow 50 kn on coast
Lo passes, and hi, over 1030 mb builds fast [under 3 hrs]
The hi forms offshore, with the lo still over E Wa
Land breezes: Small pressure gradient, from cooling at night
Downslope wind less than 10 kn, up to 1 mile offshore
E shore of N Sound noted for this, except Cultus Bay
Magnolia Bluff always has NE wind down bluff, in a N wind
With N or S winds in Sound, may be either E or W in Strait
Check pressure at Belligham, Olympia, Quillayute to forecast
Higher pressure difference causes higher speed
1 mb or less between locations causes light and variable winds
With E wind in Strait, Ediz Hook eddy may form
Wind S at Smith I., E at S San Juans, N at Trial Is., W at Ediz.
Velocity may vary greatly at different points
NAVIGATION
DEFINITIONS
Purpose: Fix position, determine CMG and VMG, avoid danger, reach destination
Navigating is easier at night: fewer visual distractions to beacons
But harder to see dangers and routes thru narrow passes
Tools: Charts, Coast Pilot, Tide/Current tables, Light List, binoculars,
calculator, dividers, chronograph, compass, plotter, knotmeter, RDF, depthsounder, GPS, Sextant and tables
Dimensions: Direction, distance, time, speed, position, depths, heights
Bearing: Compass direction from boat to observed object
Range: 2 charted objects in line from boat giving an LOP
Course (C): The rhumb line, over the ground, intended to travel
Heading (H): Direction steered as estimated to make good the course, with estimated corrections for current and leeway
Course-made-good (CMG): Actual path over the ground
Speed: Speed through the water
Speed-made-good (SMG): Actual speed over the ground
Velocity-made-good (VMG): Actual speed toward a destination
Affected by tacking angles as well as current and leeway
Line of Position (LOP): A bearing line drawn on a chart
May be from visual, electronic, or celestial source
May be an arc of a circle, e.g. celestial sights
Multiple LOPs should intersect at a large angle for accuracy
Fix (FIX): Accurate position from (combination of) bearings, distance, close fixed object [e.g. passing a buoy], depth, vertical bearing, etc.
Running fix (RFIX): LOP advanced based on time, speed, direction
Corrected for current and leeway. Limited accuracy – really a DR
Dead Reckoning (DR): Calculated course and position, without reference to visible charted objects
Based only on plotting heading and speed on the chart
Estimated Position (EP): DR corrected by est. current and leeway
Plotting: Navigation info computed and placed on a chart
Labels: Label for line placed on line, other labels not on line
Label: FIX, DR, EP, LOP; Speed; Time; Distance; Data source
Plotting formulae: D=ST, S=D/T, T=D/S
DEAD RECKONING (DR)
Purpose: Advance position from last known position by heading, speed, time – w/o current or leeway allowance
Current and leeway are estimated at beginning of each DR (hourly)
An estimated heading is set as the course to steer
DR is plotted on the chart by speed and heading from a known fix
Or from the last DR (not EP)
DR PLOTS:
Start DR plot on leaving a known position; new DR at each fix
Plot EP each hour, based on heading, est. current, and leeway
Each new hour’s plot starts from the ending DR point
EP calculated at end of each hour by cumulating all vectors
Plot EP, start new DR, whenever heading changes
Dangers: DR inaccurate at best, way off at worst if currents strong
Errors in EP result from errors in heading, current, leeway calcs.
The sector between DR and EP is most probable area boat is in
Recognize boat may even be either side
Due to stronger or weaker current, or flow in different direction
CURRENT CALCULATIONS:
“Current” includes steering error, etc
For sailing, however, leeway should be calculated separately
90 degrees to heading. Greatest when close-hauled in strong wind
Find by: H less CMG when no current, and ranges available
Vectors for current and leeway are plotted to determine each EP
Current estimates must allow for variations due to tidal changes
Average current set and drift for each hour is estimated
A fix will show errors in estimated current and leeway vectors
I.e. where boat actually is vs. where it was calculated to be
Vectors, calculated by direction, speed, and time, may determine:
Expected track & speed over ground (if boat speed and heading, and current set and speed are all known)
Set/Drift of current (if boat’s heading, CMG, and speed known)
Required heading for intended course (if current set and speed known)
Difference between DR and EP is current and leeway vectors
*0900 DR
0800 A B
FIX* C *0900 EP
Line A: Each hour, plot and label H in degrees and S in knots
Line B: Estimate combined current and leeway vectors [may not form a straight line, and may oppose each other]
Line C: Plot and label estimated CMG and resulting EP
Substantial errors can result from miscalculating both A and B
TAKING BEARINGS:
Use hand bearing compass or steering compass [less accurate]
At least 2, preferably 3, at as wide intersecting angle as possible
Two bearings on a single point can give distance off
Steer steady heading & speed, time 2 bearings on a fixed point
Larger the angle, less the current, the more accurate
Plot LOPs, open dividers to distance run (corrected for current), align dividers on LOPs parallel to estimated course [not heading]
Danger Bearings (DB)
Plot LOP outside danger to visible point on chart
As boat approaches, assure bearing to point does not cross DB
ELECTRONIC AND OTHER NAVIGATION AIDS:
[Use in conjunction w/ DR and visual observations]
GPS: Available worldwide, and accurate generally within 50’
LORAN: Supposedly being phased out. Inaccuracies in inshore waters, due to radio wave refraction, are serious!
RDF
1 mile accuracy @ 10 mile distance as good as can count on
Correction for ambiguity: Steer for few min. & see direction of change. Otherwise can think you are 180 degrees off
Depthsounder
Plan the route in advance, and follow. Make list of checkpoints
Once lost, very difficult to regain a fix
Angle back & forth over a depth contour line to follow it
Look for aberrations in the depth contour to give fix
Note rate & direction of depth change & compare with chart
Sail to one side of destination when closing coast
Then turn to follow a set depth
“Barking Dog” Navigation
Sounds, e.g. breakers, cars on a coastal highway
To follow shore, angle in & out & listen for
Must know no off-lying hazards
Use road map for better definition of shore structures
Kelp
Kelp line is on rocky bottoms up to 50′ deep
Check chart to see how close 50′ line is to shore
Water version of hiway “Fog Line”. Stay outside kelp
Caution: Strong current may sink kelp
“Bob” a Light
Move sight level up and down to check edge of light range
When closing shore, note when features first seen
Gives distance off; bearing gives LOP
Distances of visibility of objects when sitting in cockpit:
City Glow
Can show over 100 miles on a dark night
Take compass bearing on center for estimated LOP
Shipping
Usually in a well-defined lane, traveling a determinable
heading, e.g. in Strait or Sound
RULES OF THE ROAD
Buoyage system
Rule: “Red right, returning”: Red buoy to starboard coming in
Have even #s, increasing upstream. Green to port, odd #s
Red/white stripes: mid-channel
Diamond: danger. Crossed diamond: forbidden. Circle: caution
Right of way
Under power, vessel on right, or being overtaken, has right of way
Under sail, vessel on starboard, or to leeward, has right of way
Ship in its channel has right of way
Vessel fishing with marked nets out has right of way
Sound signals: 1 short: moving to own right. 2 short: moving to left.
3 short: engine astern. 5 rapid: danger