Trim tabs

smanni · Post by **smanni** » Mon Jun 26, 2006 9:40 am

hmmmm, intersting - anyone considering this?

franklyprice · Post by **franklyprice** » Mon Jun 26, 2006 12:43 pm

I may try this during the winter layup. It's a good idea and shouldn't have any downside to it. The theory is the same as the winglet on alot of newer aircraft. There is a certain amount of water that spills out the sides of the tab , not just the back side of it, the angles on the sides will effectively trap some of that energy and put it to use. I've seen rudders also use this type of thing and it does improve them also, for the same reason.

Capt. Ed · Post by **Capt. Ed** » Mon Jun 26, 2006 5:17 pm

Frank, how would you do that on a rudder without creating drag? Would you place it on the top and bottom edge? 1979 Bertram 33' FBC ALEXANDRA Port Richey, Florida HAVE YOU SIGNED UP FOR BERTRAM PRIDE '06 yet? DO IT NOW... SPACE IS LIMITED!

franklyprice · Post by **franklyprice** » Tue Jun 27, 2006 2:55 am

Ed, Yes. Top and bottom running in the direction of flow. I looked at our rudders though and it would be difficult to do because both top and bottom are angled at about 45 degrees. I have seen this done on a searay, I'm sure it was done from the factory.

Capt. Ed · Post by **Capt. Ed** » Tue Jun 27, 2006 4:03 am

A Searay? Perhaps they need it more than a Bertram! 1979 Bertram 33' FBC ALEXANDRA Port Richey, Florida HAVE YOU SIGNED UP FOR BERTRAM PRIDE '06 yet? DO IT NOW... SPACE IS LIMITED!

photo finish · Post by **photo finish** » Tue Jun 27, 2006 10:06 am

how would you attatch them?bolts? epoxy?chewing gum?

franklyprice · Post by **franklyprice** » Tue Jun 27, 2006 2:22 pm

I would weld them . In fact if I do it, I may not use angle at all, I may just extend the tab by welding some stainless to it, grinding the weld and turn it down on the sides, for a cleaner look. Remember Tim, I play with metal for a living.

photo finish · Post by **photo finish** » Tue Jun 27, 2006 3:50 pm

That is soooo cool !

smanni · Post by **smanni** » Tue Jun 27, 2006 6:58 pm

might be something I'd do - especially if there is no downside. Seems like a good way to get a little more trim-ability without going to larger tabs - which most people on here say not to anyway.

sbeer · Post by **sbeer** » Wed Jun 28, 2006 4:45 am

In a way it would act like a dol-fin. They also create alittle lift in the stern of outboards. Helps the boat jump on plane quicker. Sounds like the same concept. I like the fact of doing it on the rudders. It would act like the dol-fin on outboards. The only thing is, HOW BIG???????? Mike

photo finish · Post by **photo finish** » Wed Jun 28, 2006 5:40 am

by the way the west marine catalog sells a trim tab with the sides down turned this way. Maybe the sportfish models are different but on my boat i never use half the tab that i have now. if i tab down much my bow dives too low and steering goes squirrelly.I think Doug has also stated that he does not use much tab either.

franklyprice · Post by **franklyprice** » Wed Jun 28, 2006 12:54 pm

Tim, I know we've had this discussion before but do you have the original tabs? On mine they are quite small and limited to only an inch and a half of travel. I know they were made like this for a reason, like the boats do get squirrelly in certain conditions. like a followering sea . For this reason I'm not looking to put the giant ones like some people want to do but sometimes when I'm in no hurry, a slightly more efficient 18 knot cruise would be nice.Over 20, no need for them, as far as I'm concerned.

photo finish · Post by **photo finish** » Wed Jun 28, 2006 4:10 pm

Mine are the small stock ones.Also I am cruising 20-24 knots so perhaps with the increased speeds the tabs are not needed.Also as the fuel tank gets empty the nose dives a little also. I think with the 454s it would be something to try.

Roger That · Post by **Roger That** » Wed Jun 28, 2006 4:38 pm

I changed my small tabs to large Benet approx. 32 - 36" (i cant remember which one). But I will tell you that the large tabs make no difference in my speed. I only use the tabs in rough seas or when I am "loaded" to straighten boat out either to port or starboard. I agree with the statement that bertram knew what they were doing when they put the small tabs on! Unfortunately, I spent the money only to find that out. I believe that the sportsfish model boat runs naturally (and best) bow up. And if you try and change that with tabs, the nose digs in and you actually start draging and lose speed. The larger tabs are great to stabilize boat but dont count on any speed adjustments. My boat is repowered with 330B diamond series diesels. Roger That!