Boat Design Forums  |  Boat Design Directory  |  Boat Design Gallery  |  Boat Design Book Store  |  Thanks to Our Site Sponsors

Go Back   Boat Design Forums > Design > Powerboats
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 05-31-2011, 09:35 AM
valkon valkon is offline
 
Join Date: May 2011
Rep: 10 Posts: 1
Location: holland
Fin under boat

Hi guys

New here!
i have a question...i was thinking about putting some fins under my 20ft maxum
like the fins undeer a ski boat,hoping this would help me go in a straight line at slow speeds.

under the keel in a straght line

but i am worried than a hi speed turn would flip over the boat....what would you think

thanks Valkon
Reply With Quote
  #2  
Old 05-31-2011, 01:02 PM
PAR's Avatar
PAR PAR is offline
Yacht Designer & Builder
 
Join Date: Nov 2003
Rep: 3125 Posts: 9,403
Location: Eustis, FL
Yes a skeg or fin if you will, is going to help your tracking, particularity at low speeds, though at low speeds it needs to be a fairly large appendage. This is the rub, at high speed you want as small an appendage as you can live with, but at low speed the reverse is true.

In the end, you have to decide what you really need. If you spend a large percentage of your time at low speed, then a big skeg will help straight things out (literally), though you'll have additional drag and disturbance at high speed. A skeg will not make your boat flip over. A lot depends on you boat (it's shape), but generally boats that flip over in turns, dig in their chine(s) and started skidding sideways first, which you can feel. If you ignore this and slam down the the throttle or have attempted to execute a very sharp turn at way too high a speed, then yep, you sure as hell can "trip" over the chine and roll the boat. In reality, once the chine digs in, the out drive or outboard starts to ventilate as the boat starts hopping over the new wake it's creating with it's chine and slows down, which prevents the roll over. In extreme conditions or if the skipper has no brained himself into a hole, she'll flip, but the vast majority of the time the boat just skids, hops and pounds hard sideways, then falls into the hole it's generated with a dramatic lose of speed.

In short, no a skeg or fin will not trip your boat in turns and yes, it will help both low and high speed straight line tracking.
Reply With Quote
Reply



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
asymmetrical fin phum Boat Design 10 11-06-2010 05:57 PM
Fin keel mermont Boat Design 3 10-26-2010 01:12 PM
Fin area ivor Bittle Boat Design 17 03-12-2009 09:24 AM
where would you put a fin? Frosty Boat Design 15 03-02-2007 01:49 PM
Fin Keel CBrown Sailboats 7 08-10-2004 07:06 AM


All times are GMT -5. The time now is 07:01 PM.


Powered by: vBulletin Copyright ©2000 - 2012, Jelsoft Enterprises Ltd.
Web Site Design and Content Copyright ©1999 - 2012 Boat Design Net