Tim Tab and Hydro foil use

john cole

Petty Officer 2nd Class
Joined
Sep 16, 2011
Messages
135
This kind of ties in with my previous post on using Trim Tabs, I just installed the trim tabs a couple of weeks ago and love them, now on the real jest of my question. My out drive already has a "wing or hydrofoil" attached to it, should I just leave it on or remove it or half dozen either way? thanks in advance.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Take it off and note the results. Boat looks like a cuddy and probably difficult to get weight forward when carrying a crowd.
 

Watermann

Starmada Splash of the Year 2014
Joined
Jan 12, 2013
Messages
13,822
Put it on C List, there's plenty of under powered over weight boats out there with cheap skate owners.
 

kjsAZ

Chief Petty Officer
Joined
Jun 15, 2012
Messages
433
In my opinion that's something only you can figure out. It depends on several things like the design of the hull you have and the "normal" loads you carry and their distribution. If the hull was designed right the fin makes it worse at higher speeds. These "lifting devices" should only be required and active until you get on plane which is exactly what the trim tabs do. The fin will provide lift all the time and only makes it better when you have to much stern load or the hull has a "bow-up" design getting it above the angle it planes best.
In short: I think you should make some runs with the fin you have and then take it off and see how she handles. After that you can decide whether you leave it off or install it again.
 

john cole

Petty Officer 2nd Class
Joined
Sep 16, 2011
Messages
135
I am trending to agree with the do some runs with it off and see how the boat performs. I've done a bunch of reading and seen arguments for both and against its use. It will be interesting to see how mine performs.
In thinking about it, I would tend to think the the two would fight each other. The tabs are basically lifting the stern or holding the nose down (depending on how you look at it) and the foil is trying to do the same thing but by and opposite approach to an extent? For instance if you trying to keep you bow down you would drop your tabs and or trim the motor down which with the foil would help "lift" left your out drive or back of the boat. so in that sense they're doing the same thing. But now if you want to go faster you would retract the tabs in most instances, removing the drag. But on a hydro foil you would trim up the motor which would cause you bow to come up so there is less hull in the water meaning less friction (in theory) biggest problem there if I'm running both the tabs are still there "even retracted" helping hold the stern "up" while the foil is trying in a sense trying to push it down? Which probably causing several issues ie un-needed stress, slower speeds and more fuel consumption, this is all in theory of course. But until I can get it out this week end I won't know for sure, guess I'm just wondering, is my thinking out of line on this?
 

H20Rat

Vice Admiral
Joined
Mar 8, 2009
Messages
5,204
if I'm running both the tabs are still there "even retracted" helping hold the stern "up" while the foil is trying in a sense trying to push it down? Which probably causing several issues ie un-needed stress, slower speeds and more fuel consumption, this is all in theory of course. But until I can get it out this week end I won't know for sure, guess I'm just wondering, is my thinking out of line on this?

So when tabs are retracted and you are running at speed, they are doing very little, if any. Remember the water is coming straight off the hull, it doesn't lift up much in the foot behind the edge of the hull. One other thing to keep in mind, the two are acting differently on the boat. Tabs do not directly affect the bow, they are either lifting the stern, or they aren't. They have zero leverage. A fin on the other hand is acting well behind the rotation point, so their lifting action also has the opposite result of pushing the nose down.
 

Tabman

iboats.com Partner
Joined
Feb 21, 2002
Messages
566
Try Taking it off. If the Trim Tabs are large enough for your boat you won't need it and it will only contribute additional drag. Plus they can work against each other in certain conditions (even more drag). But, sometimes on certain heavier boats having both (or better yet, larger Trim Tabs) will work best. If you don't like the results you can always put it back on.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,282
I have both and do a dance in the bow every time I put the old girl in the water. Try it both ways and make your own mind up. But, if you end up keeping both don't tell anybody cause you'll be put down.
 
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