File - Canadian Wayfarer Association

1.3.3 Boom outhaul
Function of the outhaul
Set up the outhaul so that it is easily adjustable while sailing. Run control lines back under the
thwart (or along the side of the CB housing) but preferably to each side deck for adjustment
while sailing. A 3:1 or 4:1 purchase is effective.
• In light wind, pull the clew of the main out close to the black-band to flatten the sail, this
helps to maintain air flow over the sail. A tight outhaul also helps to loosen the leach of the
main. It is OK if the foot of the main folds into a shelf. This is necessary to flatten the sail.
• In medium air, ease the outhaul to make the sail full for max. power. Just take out the
vertical wrinkles along the foot.
• In heavy air, pull the clew out to the black band to flatten (depower) the main when going to
windward. Ease the outhaul on reaches to provide increased power for planing.
With the current trend towards close sheeting genoas, the ability to adjust tension along the
foot of the mainsail so that the bottom section of the sail can be flattened to keep the slot open
is an important control. In fact, it is all too easy to overflatten the bottom of the sail. So,
initially have the foot fuller than you think is necessary. Then, as the front of the sail
backwinds, flatten progressively until there is as little backwind as possible. This also gives the
advantage of opening out the lower leech to reduce heeling forces. In simple terms therefore,
when beating in light weather, the foot should be as tight as possible with horizontal ridges. As
soon as the crew sits on deck, the sail should be eased about 4 cm (1½”) to give some backwinding
but not too much. Then, as the helmsman has to progressively ease the main sheet, the foot
should be tensioned gradually to cut down the heeling moment. Do remember however, that if
there isn’t power in the rig to drive through waves, it pays to have the foot fuller and to accept
the backwinding. Finally, mark the control line where it leaves the boom to show the amount of
tension applied, and lead it back to the helmsman.
Outhaul Installation
You will need a swaging tool for this (or you could use pre-stretched rope instead of wire).
The inboard and outboard endplates will have to come off the boom. You will probably already
have an entry block at the aft end of the boom, but for this system, you will also need a (small!)
entry block on the underside of the boom at its inboard end. I used a HA-6 for this and put it so
close to the inboard end of the boom that I had a nasty surprise when I tried out my new
system: the gooseneck plug would no longer fit into the boom! I got around that problem by
hack-sawing off most of the plug which is now about 2 cm. long (and it has worked fine for the
past 20 years!). In retrospect, I like this system because it leaves the outhaul system nice and
close to the mast so that the outhaul is not visibly tightened when I let the boom out to a reach
or run – which it would be if I moved the entry block too far aft! A really small entry block
19