As published in the Dutch FD Newsletter, and then in the International Bulletin a few years ago. The English version has Cle Jeltes imprint on it, but I felt it was best left as it was translated, firstly, its better than anything I could write in Dutch, and secondly, we are a real international class after all.
Since racing started in FDs sailors have speed problems. Incidental or structural. After each race you will hear "all of a sudden my speed disappeared". For some speed is something magical, for some accidental but for the ones sailing upfront rational. Thinking and acting along the correct steps, together with the feeling (gained through training) will produce speed. Training is your own problem but may be we can help with the trim.
The FD is a fast boat where specially with a lot of wind big speed differences can occur. The trick of trimming is the accurate react-ing on wind changes so that the FD can be sailed at an optimum at all times. She must keep running and not stop.
This article is meant primarily for novice FD sailors and recreational sailors who want to have some more control over their boat. Of course the more advanced are allowed to have a peep in the kitchen of the competition.
Since the early eighties one development has been of extreme importance:
The so called RAKE, which is of great influence on speed and control. It has been discovered more or less at the 1983 Worlds in Australia. A not so well known Kiwi appeared to be, with much wind, a lot faster than the favourites. Noticeable was that his mast was leaning extremely backwards. This lead to many putting on a thinking cap and experimenting, with LA 84 in the back of their minds. A period with much experimenting followed.
Sails. CB position, masts, shroud positions, everything was reconsidered. Now the situation has stabilised again and boats and material are pretty identical.
With not too ancient equipment and a good trim much speed can be obtained in an FD.
Do not try to reinvent the wheel. Use those who know how to go fast. Most are willing to explain and answer questions. The FD Class has the luxury that at all European and World Championships statistics of used equipment are produced. Use them. Those materials have proved themselves and can be made to go fast. Experimenting takes an enormous amount of time and works really only for very experienced FD sailors who will actually notice the differences.
When you want to refit an old boat or build your own boat it is important to have some dimensions which are free but of great influence on trim. They constitute the basis on which to start trimming. So before you start fitting out the boat you better go to an FD event with note pad and ruler and write down the various positions of fittings and take-off points. -
The most important are:
Shroud position: 3.25 m from transom,
0.60 m from centrelineLower shrouds : on mast - just above black band for the boom
in the boat - ust aft of the shrouds
Spreaders: 40-45 cm long, pushing shrouds approx 10cm outward,
85-90cm between ends. Height about halfway between deck and jib halyard. Fine adjustment depends on type of mast, sails and crew weight
1. Shrouds
They regulate, together with the genoa-halyard, the rake. A 20cm adjustment is required. Reduction 1:24. Be sure to have the adjustment synchronous on both shrouds. Most common is a 3-sheave block on the shrouds, a double two-sheave on the anchorage in the boat and along the CB case a two-sheave with becket, adjustable on both sides. With little wind the mast will be sailed leaning slightly forward, and raking much aft with a lot of wind. Mast top moves about 1.5 m!! With very light winds the lee shroud can be loose, tightening with increasing wind to maximum with a blow.
2. Lower shrouds
Indispensable trimming item for mast and pressure control. Reduction 1:12 is adequate. Gives control on belly of the main and gap between genoa and main.
With very light winds loose, then tightened to the keep mast stiff till excessive pressure has to be released. Always check the mastbend from the trapeze before the start.
3. Genoa-halyard
Directly connected with shroud adjustment. Necessary reduction approx 1:18 with appropriate adjustment length (Coarse and fine adjustment is advisable). With little wind it must be possible to pull mast forward whilst with much wind the mast must be able to drop backwards. Adjust tension so that with little wind there is some sagging and with much wind there is enough to point. With real much wind the halyard can let go a little to get rid of some pressure.
4. Fairleads.
After a period with fixed fairleads now adjustable ones are most common. Maximum adjustment allowed is 6 cm below and 6 cm above deck, measured from top of deck to centre of sheave. The aft position is limited through a black band on deck. Athwartships no limitation. With little wind the fairleads are above deck, with increasing wind they are to disappear under the deck. Watch the gap between main and genoa. A good reference point is the distance be-tween genoa and spreader end. With very little wind approx 30 cm. some more wind 10 cm and then when pressure has to be got rid off opening up to max 50 cm. Adjustment up-down and out-in should be synchronous operational on both tacks.
5. Kicking strap
Reduction 1:12 is sufficient. Do not apply too much tension, certainly not with light winds. Important for main leech control. Make sure that with much wind in reaches the kicker is rather loose as it gives much better control on these rides. The superfluous pressure can be more easily dumped from the main and the boom is less likely to hit the water (which would be end of exer-cise)
6.Traveller
Very fancy and very expensive is the Har-ken windward sheeting traveller. Can be pulled to windward without having to re-lease the leeward side. It is preferable over other systems: in practice it proves to give better mainsail control. Also with more wind the traveller will be put a little bit to windward to obtain proper twist in the main.
7. Cunningham hole
Usually operational on both sides. Good control of mainsail belly. Tightening moves the belly forward whilst wind pressure tends to move belly aft.
8. Mainsail outhaul
A reduction of 1:4 and a clamcleat on the boom near the mast works well.
9. Centreboard
Also an important trim item. With little wind maximum down and forward. When the wind increases move aft and up. Make sure the CB has no play in the case. Forward and aft adjustment with reductions is most stylish.
10. Mastbend adjustment
A trick used recently is to have a small piece of line round the mast to produce pre-bend. Only used with little wind to bend the mast without tension on the sail so the leech can be opened up.
11. Geriatric's rope.
Not everybody uses it. About 20 cm above the main clew eyelet a second eyelet is fitted with a line running forward along the boom. With extreme rake the boom will almost hit the deck and taking in on this line will pull up the boom. The main under these condi-tions is not all that effective so speed is not affected.
MATRIX
General: Keep the boat upright, neutral on the rudder and with as much pressure as possible.
Make sure to have your own reference markings so that with each wind condition you can find immediately the right trim. This is the only way to react quickly and ac-curately to changes in the wind and finding speed will be no surprise but a logical con-sequence.
BftO-1
Shrouds leeward loose
Lower shrouds loose
Genoa halyard little sag
Fairleads above deck
Kicker loose
Traveller to windward, boom midships
Cunningham slight tension
Main foot slight tension
CB max forward, max down
Mastbend prebent, slightly leaning forward
Genoa gap approx 30cm
Genoa clew one
Helmsman forward of fairleads
Crew forward to leeward
Boat heeled to leeward
Bft2-3
Shrouds leeward tight
Lower shrouds tight, mast almost inverted
Genoa halyard tight, no sagging
Fairleads under deck
Kicker tight
Traveller windward
Cunningham loose
Main foot medium
CB 2-3cm aft, max down
Mastbend none, mast vertical
Genoa gap approx 10cm
Genoa clew one
Helmsman on fairlead
Crew forward in trapeze
Boat slight heel to leeward
Bft3-4
Shrouds tight
Lower shrouds tight, keep bottom stiff
Genoa halyard no sagging
Fairleads under deck
Kicker tight
Traveller windward
Cunningham slight tension
Main foot max tension
CB 5-6cm aft, max down
Mastbend keep stiff, some rake
Genoa gap approx 20cm
Genoa clew two
Helmsman just aft of fairlead
Crew just forward of fairlead
Boat slight heel to leeward
Bft4-5
Shrouds tight
Lower shrouds loosen some
Genoa halyard no sagging
Fairleads under deck
Kicker tight
Traveller windward
Cunningham tight
Main foot max tension
CB 15cm aft, approx 10cm up
Mastbend little, some rake
Genoa gap approx 30cm
Genoa clew two - three
Helmsman aft of fairlead
Crew at fairlead
Boat level
Bft5-6
Shrouds max tension
Lower shrouds give a little
Genoa halyard no sagging
Fairleads under deck
Kicker tight (loose reaching)
Traveller windward
Cunningham tight
Main foot max tension
CB 20cm aft, approx 10 cm up
Mastbend reasonable
Genoa gap 40cm
Genoa clew 3
Helmsman aft of fairlead
Crew on or aft of fairlead
Boat level
Bft6-7
Shrouds max tension
Lower shrouds give a little
Genoa halyard give a little
Fairleads under deck
Kicker tight
Traveller windward
Cunningham tight
Main foot tight
CB max aft, top out
Mastbend much
Genoa gap 40-50cm
Genoa clew 3-4
Helmsman aft of fairlead
Crew aft of fairlead
Boat level
Bft7+ (=Get Home!)
Shrouds max tension
Lower shrouds mast just controlable
Genoa halyard give a little
Fairleads under deck
Kicker tight
Traveller windward
Cunningham tight
Main foot tight
CB max aft, top out
Mastbend max
Genoa gap max
Genoa clew 4
Helmsman aft of fairlead
Crew aft of fairlead
Boat level (if possible)