Yachting World — February 2018

QUICK TIPS

PRACTICAL

t is easy to underestimate distances

at sea. A GPS can’t always cover

for inexperience and still the best

navigation aid is the good old ‘mark one

eyeball’. How accurate that eyeball view is

varies with experience and training.

Calibrating your judgement is an essential

skill for the navigator. Knowing where you are

is one thing, but knowing how long you can go

before you have to tack is vital. There are a few

simple tricks that can help hone what you see.

A good starting tip is to regularly play a

‘guess the distance’ quiz with other crew during

quiet moments. Then compare your estimates

with the actual distance by AIS, radar or chart.

This is often a question for a candidate on a

practical RYA Yachtmaster exam. Practice

makes a big difference and helps you to develop

this useful skill.

Keep it simple

As a navigator you have to be able to

communicate in clear language with your crew

when sailing close to a hazard. Discussing time

rather than distance can make things simpler.

For example, telling them that you have 260m

to go is of limited value, but translating that to

a time such as, “1 min 30 to tack” is something

everyone can understand.

But when at very close quarters then “Three

boatlengths to a tack,” is easy for the team to

judge. Even at short ranges it is surprisingly

easy to underestimate distances. Most

superyacht regattas now stipulate a moving

40m zone around each yacht to aid collision

avoidance. They provide each ‘afterguard’ with

a laser range finder (originally developed for

golf) and the same ‘guess the distance’ quiz

is very illuminating among highly experienced

professional sailors. I find that estimates

quickly improve by race two!

Knowing quickly if you are going to pass

ahead or behind a yacht you are converging

with is another judgement call that comes

with experience.

Get your bearings

Inshore, you can use the shoreline to help

you (see ‘making trees’ in Quick Tips, right).

But when sailing offshore, with no shoreline

behind the vessel, then regular checks with

a handbearing compass is the best method

for monitoring the potential risk of collision.

Remember that if the distance is closing and

the bearings are not changing much, if there is

any doubt then the Rule of the Road determines

that a risk of collision is ‘deemed to exist’.

Another tip when offshore is to line up the

other vessel with a particular stanchion or part

of the shrouds on your yacht, then as long as

you are still sighting from the same place you

can pick up relative movement. AIS can be a

great help in collision avoidance, but is best

used in conjunction with a compass.

Helping hand

What if another boat is ahead and you are

not sure if you are closing or not? Using an

outstretched finger placed vertically works well

if you compare the height of the yacht with,

say, your knuckle to fingertip, then check again

about three minutes later. A more accurate

way is to turn the hand-bearing compass on

its side and measure from, for example, the

deck to masthead or from the second spreader

each time you check.

Handbearing compasses have not changed

much in the last 30 years and are a great aid for

navigators, although they can be tricky to use

in a rough seas as the damped compass swings

around and you have to estimate the average

number. Again, practice is essential.

To check if you

are closing on

another boat, turn

a handbearing

compass on its

side and gauge

the height of the

boat’s mast, then

check again three

minutes later

QOne accurate method when sailing

inshore that you don’t need a compass

for, just a ‘good eye’, is the ‘making

trees’ trick. Here you watch the

converging vessel and the shoreline

behind at the same time.

QIf the boat you are converging with is

‘making trees’, in other words more

shoreline is appearing from behind his

backstay then he is ahead. Conversely

if they are ‘making trees’ out of their

forestay, then you are ahead. If there is

no bearing movement and the shoreline

appears static in relation to the other

yacht, then you need to do something

about it if you are converging with a real

risk of collision.

navigation briefing

MIKE BROUGHTON ON DISTANCES AND TRANSITS

Use transits to calculate

if you are going to cross

another boat

I

MIKE BROUGHTON has been a pro navigator for

25 years and currently races on yachts such as the

107ft superyacht Win Win. He also races and cruises

on his own Swan 48 Assuage and carries out race

tuition and navigation masterclasses.

See http://www.sjy.team

104 February 2018