Trim Problems (Smart Tabs?)

[ILOVEBEER]

Hey Guys, I have a 1998 Sea Ray Sig. Bow rider 190. When I go WOT from a stop, the bow really rises but gets on plane fairly quickly (outdrive trim full down). Once on plane, the boat feels like it is trying to sink the bow (fighting itself) so a quarter up adjustment of the outdrive trim raises the bow and gives me a few extra MPH. Now in stabalized cruise if I increase the throttle, the enfine RPM increase RAPIDLY with no increase in speed or pull. It almost feels like the prop is cavitating and I have to quickly trim down to fix the problem. Once stabilized again, I can retrim the bow down pressure out. Is this cavitation normal? Will anything prevent this? I was thinking of purchasing Smart tabs but I want to be sure they will help. Any input will be appreciated.<br /><br />Thanks a bunch.

 

[QC]

Re: Trim Problems (Smart Tabs?)

Well . . .<br /><br />1) It is probably ventilation actually, not cavitation and it is pretty normal if you are trimmed out a little too high at mid range speeds<br /><br />2) A prop change alone could help minimize this, so you should probably look around in the prop forum<br /><br />3) Sounds like she has a little more weight in the bow than you need/want for good balance. I like my boats balanced so that they will porpoise slightly when trimmed out at wide open throttle (WOT), this tells me that the weight balance is just about perfect. I would move some weight aft before I did anything else to see if that helps with the ventilation. This will make your bow rise at first throttle a little worse, stay tuned.<br /><br />4) You need to think of your trim as dynamic. Different trim settings for different speeds, conditions etc. There is no perfect trim setting for all around use. In (down) to get her up on plane, and then trim out (up) to adjust for speed, efficiency, comfort etc.. You will want to come in for hard turns too.<br /><br />5) Trim tabs or Smart tabs will eliminate the problem of the porpoise once the balance is right AND it will solve the bow rise issue that you noted in the first line. And . . . they will help you with the low-speed wander we discussed in the other thread.<br /><br />Good luck!!!

 

[paulie0735]

Re: Trim Problems (Smart Tabs?)

QC has covered it all nicely, but you may just be using to much trim. I have had people say that they aren’t using to much trim because the gauge said "I still had some left". Trim is an adjustment so you can set the engine at the right angle for any given speed or load. It’s not designed to be used over its full range on every boat. Trim tabs will improve your boat but I think you already knew that. This is a different issue and its worth doing some homework on the correct use of trim and how it affects the way your boat performs.