File - Canadian Wayfarer Association

• What we therefore do is crank up the tension with the halyard and then take up any slack in
the forestay with the aforementioned tackle. Once the stay tackle is well tightened and
cleated, it keeps the rig tension required for pre-bend while the halyard can be slackened
off to give us any amount of luff sag that feels comfortable.
On “Shades”, we have cut enough off the bottom of our forestay to accommodate a 30-40 cm.
tackle which consists of about 1.5 metres of 4 mm. pre-stretch line. This is tied to the becket of
an RWO #R4959 (V-jamming block with becket intended for windsurfing use) attached to the
bow plate where the forestay used to be attached from the becket, the line goes up about 30
cm. to an RWO micro-block (#R1530) which has been swaged into the new loop at the lower end
of the forestay the line then leads down around the sheave of the R4959 before exiting through
the V-jammer which we have facing aft. The amount of pre-bend you get depends on:
• how far aft your spreaders are angled
• the amount of rig tension applied
• the inherent flexibility of your mast section
Note: Abbott masts are harder to pre-bend but word from the Fanshawe Fleet is that using a
minimum diameter 6 mm (¼”) mast pivot pin facilitates such bend.
1.2.4 mast rake setup
Tighten the jib halyard to put tension on the rig but not enough to cause mast bend.
Fasten a tape measure to the main halyard and hoist to the top of the mast.
Check the distance from the top of the mast to the bottom of the bridge created by the
traveller bar over the transom opening for the tiller. This should be 716,3, +/- 1cm (23’ 6” +/-½”).
Adjust the two shroud lengths evenly until the desired rake is set. For shrouds with the
adjusting plates, each hole change affects the measured mast rake by 5 cm (2”) 7 .
Check that the mast is perfectly vertical by measuring the distance from the top of the mast to
each end of the traveller. This distance should ideally be the same to both sides 8 .
Place plastic tubes over the shroud adjustment plates, or wrap with plastic sheet to protect the
pins and prevent them from coming loose or tearing sails.
1.2.5 mast bend check
The mast should be as straight as possible athwartships (from side to side) while under sailing
load. At the same time, the ideally curved mast would have fore and aft bend such that the
mainsail, throughout its entire height, has a fair, even curve from luff to leech.
• If the mast has too little bend, you will get the draft too far forward in the main (see top
illustration, below)
• Too much bend flattens the forward part of the main excessively (middle illustration, below)
• The right amount of bend matches the luff curve installed by the sailmaker and gives a nice
even curve from luff to leech (bottom diagram, below)
7
Al Schönborn’s note: Shroud plates with double rows of offset holes give 2,5 cm changes as you
move diagonally up or down.
8
Al Schönborn’s note: A difference of up to 6 mm (¼”) is no big deal in my opinion!
10