Replacing Trim Tabs To Improve Performance

[Alex F]

Calling all captains for brain-storming the tabs topic.

We have a thread "320 DA Driving Qualities". One of the issues we're looking to resolve is that the boat is riding bow high and you really need to use tabs and higher RPMs/Speed to get it lower (fuel economy is out of the window in this case). We're trying to find if a replacing original trim tabs will help. According to the Bennette chart this boat has way too small tabs installed. They claim it needs 36" x 9" tabs. Theoretically, large tabs should help the boat stay on plane with lower RPMs/speed keeping the bow lower.

Do we have some tabs experts that can share some light in this?

Thanks,
Alex.

 

[Dave S]

I am no expert but a larger surface area on a tab will certainly give more lift. I would also think it could be a bit dangerous as well if the tab is not sized properly. The 240DA and 260DA are good examples of this. I know how severely my 260DA can lean or steer if a tab is deployed too fast or if they are both not deployed evenly. Now imagine how much worse that problem would be with a larger tab.:wow: I think it could be downright dangerous!:smt100

I don't know how one goes about assessing the benefits versus the possible risks associated with larger tabs. But I would think most boat manufacturers have looked at this issue and installed the tab that will work the best on any given model with out causing potential problems.

But then what do I know.........I am not a tab expert.:smt009

 

[Alex F]

Dave,
Interesting point. But, from my experiance on 240 I think the tabs are on the slow side, not fast to introduce any danger. I also feel that my 240 could use bigger tabs. On the same talking, if the larger tabs would be dengerous why would a company that makes them suggest that you need bigger size? I think it's the boat factury puts the least expensive application applicable for the vessel.

Hust my 2c.

Alex.

 

[LtCdr. Augs]

My 260 as well, if I deploy the tabs too quickly, major effects to yaw at plaining speeds. I've learned the hard way to tap and wait.

AngleAugs

 

[Dave S]

Alex

I think the newer (2005 and up) 240DA and 260DA are also more sensitive to trim tabs than your particular boat is. On a 320 maybe a bigger tab is the answer. I just don't feel qualified to answer beyond what I already stated.

Dave