I've just spent a lot of time doing up the foils on my Laser4000.  What prompted me was the extreme care the International14 guys expend on their foils.  Being tippy - especially with the board up - we tend to come ashore with half board and whip it out as soon as it touches but this does mean a bit of abrasion on the bottom leading edge.  Similarly the rudder gets released but has to hit the bottom to tip it up - again resulting in a slightly flattened leading edge at the bottom.

How do the 14s get ashore and keep their foils so good, or do they refinish them each week?

How important is it to have smooth foils? Does anybody have any experience which will help quantify this?

The thing to remember about foils is that even though they're relatively small compared to the sails, they're operating in water which is 800 times the density of air. So a well finished foil is undoubtably an effective way to better boat speed.

Having said that, maybe I should pay some attention to my own foils. The guy who I bought my 4000 off was also a windsurfer and spray painted the daggerboard luminous orange! Very good for when you capsize and also for those screaming reaches when the daggerboard is partially out of the water.

The practical answer to damaged foils is to have a training set that can be dinged etc, and a special pristine/as new set for those more important races.

The thing you have to remember with the foils and the hull is the more perfect the finish the more effective the foils will be. A boat builder once tried explaining this to me by saying a chip or bit of damage will have a similar effect to weed in that it will disturb the flow of the water over the foils which will create more drag and slow you down (obviously not to the same extent as weed but every little counts), so anything you can do to improve this will be beneficial.

Yeah foils are very important, but then again so many things are. take for example you rudder if you move it by 5degrees this has the same effect as outting you leg in the wwater to slow you down, why it is so important to use as little rudder as posible. get everything else up to perfect level and then do the foils, it will only make a diference if the rest of the boat and sailing is up the that standard.

I agree with that. You need to get everything up to the best standard possible weather it may be your boat or sailing skills, however don’t make the mistake of thinking “I don’t need to do that its only a small thing” because all the little things add up to a big thing, bringing you foils up to a good standard may gain you a few boat lengths and in a close race could make all the difference.

Yeah sailing skills are definitely the thing to worry about first but once you get your sailing up to scratch, good boat preparation will win you races.

By being very careful! Actually, it probably makes more difference with our laminar-flow sections because there's a tangible benefit to keeping everything laminar, whereas with a turbulent-flow section (which I assume the production boats have) there's much less downside. But a good 14 crew is super-careful with the foils, and is willing to get very wet in order to avoid pranging them. If you sail in with the board half-way up and jump out when the water's still 4 feet deep you should be absolutely fine. At an unfamiliar venue, use other crews who have already jumped out to gauge the depth.

We do also do a fair bit of sailing in Chichester Harbour, where running aground is much more likely and can happen at considerable speed. Options here are to take less risks when travelling at speed or where you believe the bottom may be hard, and to pay close attention to other boats! It is often better to be twin wiring when you hit the bottom because the board only has to absorb the momentum of a relatively light boat (helm and crew go round the forestay). But 14 boards are pretty well-built so even a big crash just tends to wipe out the bottom couple of inches, which are relatively easy to reconstruct (an hour or two's work).

As an aside, the Ovi 1 14 was (some time ago) sold with a stock 49er board, which was pretty useless. Just about everyone threw it in the attic and had a decent one built, and it made a massive difference!

Cheers,

Dave

Actually, no. A laminar flow section operating in its laminar flow bucket will have lower drag than a similar turbulent-flow section. One way to illustrate this is to think of all the small-scale movements inherent in a turbulent flow. The energy to create these movements must have come from somewhere, and it is extracted from the kinetic energy of the foil as drag.

The big deal with laminar sections is that they can get a lot draggier outside the laminar flow bucket, so there's a real incentive to keep them within it. With a turbulent-flow section you don't get the same step change (even though it may be more efficient than the laminar flow section outside its bucket) so the incremental cost of imperfections is smaller.

Dave