Yachting World — February 2018

masterclass WITH PIP HARE

HOW TO HANDLE BEAM SEAS

Avoid big beam seas if at all possible,

but if you do get caught out in these

conditions make sure washboards are

in and tied in place. Crew should be

harnessed on short tethers, keep a good

look out using AIS and radar and ensure

everything below is well stowed with locker

doors, top opening fridges and floorboards

secured in place.

PRECAUTIONS

PRACTICAL

Employ all of your senses to dial

into wave patterns; you will start

to sense the size of oncoming

waves by how the boat feels

underneath you. Look for relatively

flat spots between them and steer

dynamically from one to the next.

If you are not able to avoid a high

crest or breaker, take action to

minimise its impact on your hull

by heading up or down. Don’t

underestimate how challenging

helming can be, so don’t rely on

one person and if there is the option to alter

course, then take it.

Autopilot settings

Older generation autopilots can really struggle

with beam sea conditions and usually require

tuning. Here are a number of pointers to help:

Remember sail trim: if your pilot is constantly

rounding up when you heel first try more twist,

then reef. In big conditions set the pilot to steer

a true wind angle. If your system does not have

ig beam seas can be the most

challenging, unpleasant and dangerous

of all conditions to sail in. Exposing

the entire length of your vessel broadside to

oncoming waves allows the energy in those

waves to have maximum impact on your hull.

This causes excessive heeling moment, which

can result in broaching or, in extreme scenarios,

a risk of inversion.

Extreme conditions should, if possible, be

avoided but here are my tips for how to handle

the top end of manageable beam seas.

Passage planning

Use wave buoy data and wave height forecasts

to assess sea conditions. Pay careful attention

at the passage of fronts; a rapid change in wind

direction will often cause big seas to break.

Depending on hull characteristics, wave

heights of as little as 30 per cent of your length

overall can start to become dangerous beam-

on, so consider alternative routes early. Most

routing software has an option to avoid waves

over a certain height but make sure your GRIB

files include wave data.

Sail setting

Sailing fast through beam seas will allow your

helmsman to steer around waves, reducing

their impact on your hull; so don’t shorten sail

too early. That said, your sails should be set to

limit heel as the force of oncoming waves will

already be heeling the boat over.

When sailing in larger waves your apparent

wind speed and wind angle can change so sail

shapes should also be forgiving to allow for

this. Go to town on twist: the bigger the waves,

the more the twist. Slide the jib cars back to

open the top of the headsail if you normally

reach using an outboard lead, and consider

moving the sheet to the inboard upwind track

as waves get bigger. Soften your mainsail leech

by moving your traveller up the track, easing

the mainsheet and vang and pulling on your

backstay. Shorten sail when the combined

heeling moment from waves and wind feels too

much. You may need to harden up the leeches

immediately after reefing, putting power back

into the top of your sails to keep sufficient

speed and manoeuvrability. As conditions

continue to build apply twist again.

Helming

Helming in big beam seas takes skill and

concentration. Good helming in these

circumstances is about anticipation and feel.

this function consider changing course to head

into the waves.

Bear in mind that your pilot cannot see

oncoming waves and does not care about

your welfare; try actively steering through

wave sets using the control pad. This is

less tiring for the helmsperson and more

comfortable for the crew (remote controllers

are great for this).

Increase response or gain so the number and

size of corrections the pilot makes per minute

matches those of your helmsman. Also increase

counter rudder settings if your pilot is weaving

an ‘S’ shape after corrections. And increase

wind damping or decrease wind response to

allow for the amount of extra movement at the

masthead caused by wave action

Charge your batteries as this will be a power-

hungry point of sail for the pilot. Some modern

pilots are now able to measure pitch and yaw

and automatically adjust settings to match

whatever the conditions.

Shortening sail reduces

the combined heeling

moment from waves and

wind to reduce the risk of

a broach or knockdown

If you can, maintaining speed through beam

seas will help the helmsman to steer around the

waves, but don’t shorten sail too early

B

InsectWorld

Kurt Arrigo

106 February 2018