turn fin

[thunderstruck]

hi guys i have a boat that is having trouble turning.
the boat is a 12.5 ft mono hull with a 18hp nissan/tohatsu my top speed is 40mph and i am thinking of putting a turn fin on would this help ? or are there any other things you can do?
cheers thunderstruck.http://s973.photobucket.com/albums/ae213/vo100thunderstruck/?action=view&current=main-1.jpghttp://s973.photobucket.com/albums/ae213/vo100thunderstruck/?action=view&current=main-1.jpg#!oZZ2QQcurrentZZhttp%3A%2F%2Fs973.photobucke t.com%2Falbums%2Fae213%2Fvo100thunderstruck%2F%3Fa ction%3Dview%26current%3Dmain-3.jpg%26http://s973.photobucket.com/albums/ae213/vo100thunderstruck/?action=view&current=main-1.jpg#!oZZ3QQcurrentZZhttp%3A%2F%2Fs973.photobucke t.com%2Falbums%2Fae213%2Fvo100thunderstruck%2F%3Fa ction%3Dview%26current%3Dmain-2.jpg%26

[Skoontz]

When you say monohull, is that with a deep vee like many of the picture show on BRF? If so we used to run a piece of 2"x2" aluminum angle iron on the outside rear so when the boat flopped on one side or the other, the aluminum would bite the water and would turn tight. When you are flying the boat in a straight line, it wont even touch the water.

[thunderstruck]

hi the boat is a deep v at the bow and a shallow v at the rear.
what would the fin do if it is on the water {going in a straight line} ?.
cheers thunderstruck

[Skoontz]

Thats just it, by putting it on the outside rear corners it does not touch the water until you turn the boat. When the boat flops to the side you turn on, the angle iron cuts into the water and works like a fin.

[ToneDef]

If you have a very shallow vee in the rear, the fin may be in contact with the water regardless of your turning situation. My 8' is a monohull, and as per the building instructions I've got a single 6" skeg placed along the centerline of the bottom, apprx. 36" forward of transom. She tends to 'push' in the turns as it is, and I don't think I'd want to try running it without the fin! SLide central!