The A-Class is in the midst of a foil evolution, and most boat owners must be wondering how this affects them.
The following is a question from Bob Hodges and the answer from Peter-Jan Dwarshuis at DNA. Thanks to Bob and Peter for sharing.
Hope all is well for you and the weather is getting warmer for good sailing.
I have a question for you. Would a retrofit of a DNA to top insert J boards allow a fit in the future of bottom insert boards if Rule 8 is removed from the A-Class rules and bottom insert boards are allowed?
I would hope to only do a major modification to my boat once to allow the flexibility for both.
Thanks for any insight.
The dagger board trunks for the J boards are very wide, about every board you can think of will fit in there.
There are two ways of building a wide case to fit “insert from the top” J boards :
1. The closed prefab banana shaped trunk , which has an inner and outer wall , just like a normal daggerboard case
2. Another method is to use the outer hull wall as the outer wall of the case and only close it to the inside with an omega shaped box. This is lighter and wider, disadvantage is that in light winds you drag more water around.
Quite a few Europeans have J boards now and are flying around. In real wind – stable conditions it is pretty stable and controllable. (like the nice Schreurer video on the Catsailor website). When its fluky and gusty, it’s very twitchy and nervous and not very stable at all. The Exploder boards are huge and asymmetric, I believe overkill for Dutch windy conditions, unless you are Nathan Outteridge or Glenn Ashby. Our boards are less extreme, but when you make sure the rake angle can go up to about 5 degrees, then we lift off just as easy as the Exploder while keeping the possibility to “switch the lift off “. It is all a compromise what to choose, like they found out in the Moth class .
BTW, a good alternative to trapezing foiling is just “sitting in hiking” and still foiling! Especially above 15 knots this ‘low foiling mode’ is extremely efficient. safe and very deep. Hard to beat unless you are an expert trapezing and foiling. The sailor has to find the right technique and settings, but once you get this right it’s great fun and less tricky then foiling trapezing, which is hard above 15 knots tws for the normal weekend sailor like ourselves.
Development goes very quick at the moment, and I guess after this EU season, we’ll know for 90 % what is the best configuration. The key is in the rudder foil size and setting. Recently I have tested the Paradox , the Exploder, standard DNA winglets, some proto DNA L rudders, and some proto DNA deep T rudders. The Paradox rudders flexed more than I expected (around 100mm) so not sure I did not get a set that were correctly built. The Exploders are stiff, but seemed a bit less forgiving stall-wise to what I am used to. The standard DNA’s felt best (and familiar) but are too short when you have waves more than 1 ft. The L’ s are most promising , giving very little drag in my opinion. We need more testing before considering making a production mould .
So, now you are a bit updated, because the information on the sailing websites doesn’t provide straight forward information like this.
PJ – DNA/HOLLAND COMPOSITES