View Full Version : trim tabs and props

11-17-2005, 01:38 PM
I just bought a (new to me-2001) seaswirl striper with an IO 5.0 volvo penta and volvo out drive. It has a 23deg. prop and electric/hydrolic trim tabs. With the tabs flat with the boat it really struggles to get up on plane. If I have the tabs down will that help? Is the prop too much? I do have a 17 deg. prop for it but that will add another 1200 rpm's and I would rather not push the motor that much. Thanks for any help and advice, Smithstation

11-17-2005, 04:33 PM
for the prop you must first find out what the maximum rpm for the engine is , say its 5000 for example take your boat to some calm water with just you in the boat no extra weight and see if you can reach that max rpm if you cant try the 17 pitch prop, for each degeree in pitch you should achieve 200-300 rpm you want to be able to reach that max rpm but not go over. of course you dont want to be running your engine at max rpm all the time. For the trim tabs you want to start off with them in a down position and as you get on plane raise them up untill you achieve a good running level. good luck I hope that will help.

11-17-2005, 05:49 PM
Mostly the trim tabs are for leveling your boat when you're heavy on one side or the other, the boat should plane with them all the way up. I'd say it's the prop, since you have a 17, give it a try, you'll be surprised at the difference from the 23. You will give up some top end speed, but who goes top speed anyway?

11-17-2005, 06:43 PM
but who goes top speed anyway?


11-18-2005, 04:31 AM
I've never use my trim tabs to get on plane, in fact when I'm on plane and put both down it feels like I'm dragging another boat.

11-18-2005, 08:20 AM
Some deep V fiberglass boats that are stern heavy (typically stern-drive powered) need to have the tabs employed in order to get them over the top. Once they get on plane, you can trim the tabs back up.

Follow Sea_Snake's advice for choosing the right prop. Your engine will not work as hard with the 17" prop and as long as you top out below the manufacturer's recommended rpm limit, it will generally provide better overall performance than a higher pitched prop.

Mickey, your boat is not a true deep V and with you up front it is definitely not stern heavy. ;D

11-18-2005, 09:34 AM
Thanks everyone. In the owners manuel it says not to go over the 5600 rpm mark for optimal running. The guy I bought the boat from took it to Canada and fished some lakes that were at or below sea level. That is where and why he bought the 23 prop. It was used up at Tahoe with the 17. I plan on fishing the delta and foot hill lakes, maybe I can find someone and trade the 23 for a 21 or 19. what do you guys think? Thanks again for the advice I really appreciate it. :D