Gibing Dagger Boards?

The thought behind gybing boards is that the board rotates along its axis (top to bottom) such that the leading edge is rotated slightly to windward while going upwind. This provides additional lift to windward while going upwind. Downwind you want them to do the opposite or be nuetral.

The trick is to make them behave this way automatically, which isnt easy, and make sure they dont get stuck in the wrong direction. Going along with both boards engaged in the opposite directions would be really slow.

Its interesting the the F18 rules allows gybing boards.

I was toying with just making the port dagger gybe so that I could engage it upwind on a starboard run and leave the other one alone, so at a minimum you would only have to deal with one board, and the risk of it gettting stuck in would be lower.

Has any other production cat come with gybing boards? I dont know of any. Have they been proven to be faster?

Bill

AFAIK gybing boards are illegal and are NOT used on this F18

Must be some bad info on that website.
What about the canted hulls?

Where does it say in the F18 rules that gybing daggerboards are not legal? This is from the rules.

After sailing the new boat with and without gybing boards it did not seem enough difference in performance. I thought that Pete decided not to use them on the boat.

The hulls are canted to allow the daggerboards to be canted. I would say about 4 degrees. This means that they have two molds for the boat one for starboard and one for port.

Dan

Dave,
The wording of the rules doesnt specifically prohibit gybing boards, but if you read between the lines, you can guess that they are not in the spirit of the F18 ruleset.

The line "being in the vertical plan (plane?) of the hulls" and "appendages must be symmetical." would indicate that they are not in the spirit of the rule. But you could always argue that point.

And you can make canted hulls from the same mold as long as you add a wedge to the beam socket on the inside halve, or fill it in later with goo. Being a production boat they probably have two differient molds, but its not a requirement.

Bill

Mystere Twister (F18) came out with gybing boards. However no catamaran has yet proven that gybing boards are advantagious. On monohulls (only one board to worry about) it is sometimes used.

Canted ? Most F18's have done away with hull canting. There doesn't seem to be to much performance gain if any. Non-canted hulls are cheaper to produce (need only one mould) This is one reason why current F16's don't have canted hulls. With the F18 world champion boat of the last years being non-canted designs : Tiger and Cirrus F18's and to top 20 being dominated by non-canted designs. One can have a good argument of whu canted hulls are not needed.

Wouter

Yes the point about gybing boards is debatable. I would think that before anyone were to build a boat for manufacture, not just one-off, they would have first thought long and hard about it. I am guessing that Pete did not just arbitrarly decide that would be the thing to do.

I know you could make the canting hulls with mold plugs. That would be the best choice if you are making just a few of the boats. These are two full molds though, one for each hull. They are gearing up to make a large number of boats. More than one mold will be needed for the planned production of the boats. Instead of making a starboard hull then putting in the plugs, making the port hull and so on. They are making different molds as they will always make more than one hull at a time. Why worry about what the plugged area will look like if you plan on doing that much production.

Dan

The Taipan 5.7 has canted hulls. The general consensus of those who have sailed them extensivelly is that there is little, if any at all improvement. Even one of the Taipan designers, Jim Boyer, said that he preferred the 5.7 without the canted hulls. Attached is a bow photo of the 5.7. You can clearly see the outward canting.

I'm not so sure of the canted hulls as I am certain that your Taipan 5.7 has Peyronie's Disease. Tough break for you...

Peyronie's Disease