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Porpoising

Posted: Mon Nov 07, 2016 5:57 am
by brozzi
After replacing my transom on my 1995 Excel, and adding a E-tec 200 H.O, the boat porpoises alot sometimes really bad. It seemed to happen after i had to lower the outboard to the very top hole because of the way this Excel's hull is constructed. Trim tabs dont do much to correct the problem so i'm thinking of adding weight in the bow.
Anyone else have this issue, anyone have my 23' excel WA?
I know the prior owner had a 200 Ocean Runner on her with no issues so whats my answer? Anyone?

Thanks

btw i am getting 5500 rpm's - 44 mph - and the A/V plate is riding on the water column so its rigged correctly

Re: Porpoising

Posted: Mon Jan 30, 2017 7:50 pm
by Pln28
What kind of prop are you running? I have the same issue my etec will not drop down to the last hole due to the steering linkage sitting on top of the transom. Still bow wants point straight up on hole shot. I correct it with the motor trim.

Re: Porpoising

Posted: Tue Jan 31, 2017 5:11 am
by brozzi
I dropped down to a Rebel 17p from a 19p. It seems to be perfect for that boat and yes hole shot with bow straight up is exactly the same as mine. It levels out quick though. Again my problem is porpoising. I'm going to throw a 100 lbs in the anchor line compartment in the bow to see if that solves the problem. Does your Wellcraft have the same step configuration in the stern as mine necessitating dropping the engine all the way down?

Re: Porpoising

Posted: Tue Jan 31, 2017 3:19 pm
by Pln28
I believe it does, if you are reffering to the cut out in the transom. Have you had any issues with boat leaning to port underpower? I am currently running a 19' pitch and my boat doesnt get on plane until I'm doing 25 to 30mph.
I have noticed porpising as well that is a stern heavy boat especially with 100 gallons of fuel.

Re: Porpoising

Posted: Wed Feb 01, 2017 6:53 am
by brozzi
Yea just the way the boat sits in the water, you can tell she is stern heavy. I also replaced and modified the transom so she is heavier there now anyways. Most boats including my Grady White lean to port from the rotation of the prop. Trim tabs easily solve that issue. Porpoising though wont be solved with the trim tabs at least as far as i have seen so more weight up front may be the answer. I'll let you know this spring.

Re: Porpoising

Posted: Sat Feb 04, 2017 3:03 pm
by reelfast220sportsman
try a 4 blade it will lift the stern better. ken at prop gods was very helpful to me over the years.

Re: Porpoising

Posted: Wed Apr 19, 2017 6:09 pm
by Helldo
Get a hydrofoil

Re: Porpoising

Posted: Mon May 22, 2017 3:32 pm
by PaulCuddy
I have the same issue with my 1996 238 CCF and an 2005 Etec 250hp. Currently running 3 hole from the bottom. I have a 4 blade Turning Point 17p SST prop. I get the right rpms at WOT and top out at 42mph GPS. Takes about 3000 rpm to stay on plane. I have nauticus automatic tabs on it and they create some drag at idle but do help. None the less I end up tucking the motor in to stop the porpoising. I have inquired about motor height and transom wedges as well as raising the motor. Was wondering if there are any suggestions.

Re: Porpoising

Posted: Tue May 23, 2017 6:33 am
by brozzi
I put 75 lbs of weight in the bow which helped a great deal. I may actually bring the weight up to 100 lbs to counter my cooler being in the stern during fishing season which really just started. My outboard is as low on the transom as can be and still see the A/V plate while running. The stepped up design of the hull at the stern / transom is poorly designed so even while having 25" from top to bottom, it really more like 28' in my opinion. I have never seen a step up like this in any boat ive owned. I'm running a Rebel 17p which is giving me the appropriate rpm's and this boat can do 45 mph wot. I'm thinking before u do anything make sure the outboard height is correct by planing off and seeing where your A/V plate is riding then add weight to the bow to see if that helps. Please let us know.
btw i do use the trim tabs but only minimally, mainly to level the boat when trimmed out. It does create drag.

Re: Porpoising

Posted: Tue May 23, 2017 6:49 am
by brozzi
There is your stepped up design flaw as well as mine!