Porpoising Problem

P

Pedro13

New Member
Jun 16, 2009
5
British Columbia - Canada
Hi guys - this is my first post.

I previously owned a 1993 Fourwinns 180 powered by a 3.0l. This was a great boat with a rock solid feel in all conditions it just lacked power. I was really excited when i upgraded and just bought a 2005 Sea Ray 185 sport with a alpha 1 outdrive and 190hp.
I am happy with the extra power but find that the porpoising at speeds above 40mph is unacceptable - top speed is around 50mph. I first operated the boat with the stock 23" pitch 3 blade alum prop and switched to a 21" pitch 3 blade alum prop. I am thinking this switch in prop size may have made the porpoising worse (not sure yet).
At the end of the day with either prop i feel the porpoising problem is a real issue. I have friends with 18foot larsons that don't exhibit this problem....
Are others having this problem as well?
Are there any solutions? I understand there are smart tabs out there that may work...I am just leary of drilling into my transum and really am discouraged that such a small boat would need trim tabs.
Would a high five prop help?
Thanks..
 
What happens when you trim your drive all the way down? Could be a weight balance issue. Maybe a fin added to the outdrive would be the most economical answer.
 
My first Sea Ray was a 1997 190 Signiture Series with a 5.7 V8.

This boat would porpoise as well unless it was trimed just right. I was told by a dealer that a majority of the 190's came with a smaller motor and the weight of the 5.7 contributed to the problem. The boat had a whale tail on it and it helped but getting the right amount of trim was crucial on that boat. Once the boat got on plane you could not trim up any higher then the second indicator on the guage. It was fine at that spot and when the drive was all the way down.

I agree with the last post it could be a weight distribution problem, it does not take much on the smaller crafts.

Keep us informed on your findings.
 
Welcome, please put your boat info in your signature line.

If you had it trimmed down I would next try shifting some weight to the front. Do you have some unecessary weight in the back that you could eliminate?
 
I have a 195 with 190 hp 4.3. I only experience porpoising when the drive is trimmed all the way up. No problem when trimmed down slightly from full up. The porpoising is more noticable when there are four people on board (two in captains chairs and two in the rear bench seat).
 
Thanks for the responses guys.
Yes, it porpoises when trimmed out quite a bit...trying to get the speed up.
When I trim it down the porpoising stops - but I have to trim it down quite a bit and therefore lose some speed.
I do have an extra battery for the stereo I got installed and that is also at the back of the boat (opposite side as my other battery). That is the only significant weight issue - no weight in the bow.
Next time out I will look at my speed and trim carefully and report back at exactly what speed the porpoising occurs at and how it reacts to trim....it just seemed to porpoise way to easily at a relatively slow speed (below 45mph).
I may be leaning towards smart tabs but you just don't see many boats this size with tabs in this neck of the woods.....any thoughts on these smart tabs....high five props???
Pete
note: i will update my signature so it has the info..tried earlier???
 
Thanks again...will kepp you posted.
One more try without fins/tabs...
I think I am leaning towards the smart tabs...
Wondering why the specs say 80lb actuator for boats my size while Midway and others ended up w 60lbs??? Seems to me if we are drilling holes in our boats this would have been figured out already....I realize you can cahnge the actuators after the fact it just makes you wonder what else may be miscalculated???
 
I put up with the same problem for years because I did not want to drill holes in my transom. I finally got to the point where I would do anything to fix the problem so I installed a set of Bennett hydraulic tabs. Now I have control over the attatude of my boat and no longer have to put up with the pounding. They look kinda cool and the ride is 100% better. I chose hydraulic over Smart tabs because I wanted to be able to make the adjustments myself. I cannot believe I waited so long. Either way you will not regret it.
 
Last edited:
I just installed smart tabs (SX) on my 185 sport....

I went with the 60lb and I'm currently set in position 3.
I tried position 2 this weekend and was very surprised that there was a significant difference between 2 & 3 (same conditions, same number of riders)

I'll be sticking with 60lb in position 3

Good luck with whatever you choose :)
 
I'm with Mac on this one, go for the Bennet hydraulic set. I've had or put them on every boat I've ever owned, not just for porpoising but for attitude reasons. Sometimes you end up with more people on one side and it's just easier to adjust without telling people to move. It also helps tremendously with cross winds, you can lean your boat to either side and relieve the wave pounding. Also, different props will not change the issue.
Good luck!
 
A 4-blade prop is considered a stern-lift prop. They also help with porpoising. I'd check around and see if you can find one to try before I drilled any holes.
 
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