New boat handling issues...please help!!

[teamclose]

Last fall i won a Polar Kraft mv 2096 xcc w/ a 90 4 stroke Suzuki at the Cabela's catfish tourny. the problem im having is i can only run the boat trimmed all the way down without it severly porpoising.

the boat has a 30 gal fuel tank in the floor towards the bow, and the battery compartment is just forward of the transom. the only extra weight i added was a graph and a extra optima battery in the battery compartment, and i also run a 30 gal bait tank in the front of the boat.

i have had the motor at all different mounting positions, both with a manual jack plate and without, and i currently have a transom wedge plate on. nothing has made a difference.

any help or suggestions would be appreciated!!

 

[tashasdaddy]

Re: New boat handling issues...please help!!

if Johns company can't help you, no one can. read this


http://forums.iboats.com/bbBoard.cgi?a=viewthread;fid=1;gtid=1267782

 

[QC]

Re: New boat handling issues...please help!!

Welcome to iboats teamclose. I think we can get you fixed up although I am concerned as you already have a lot of weight forward, and you tried the motor mounted directly to the transom . . .

I had a boat with a really nasty porpoise and the only thing that would completely eliminate it was trim tabs run pretty far down even at high speeds. They did allow me to use the drive trim though, and the boat was still pretty fast. I wonder if there might be a hook in that hull. Have you put a straight edge on it?

 

[teamclose]

Re: New boat handling issues...please help!!

QC-
the boat has the same handling problem w/ or w/out the bait tank. as far as the hook in the hull i have not checked that bc i assumed since it was a brand new boat that it wouldnt be an issue.
i just figured that polar kraft would make a boat that would run right w/out making major changes?

as far as the trim tabs, how much do they affect the top end speed? the boat runs 38 gps now but thats with the motor trimmed all the way down and i still have 1000 rpms left. i didnt want to buy another prop until i got the handling issue fixed. dont know if the prop has something to do with it?

 

[Gary H NC]

Re: New boat handling issues...please help!!

Welcome teamclose,
Actually the Smart tabs will let you trim the engine out more without porpoising and will increase top end speed.
Before you do any major changes call John at Nauticus.
He is a great guy to deal with and can help you with your problem.

John DeAgro....800-233-0194

 

[QC]

Re: New boat handling issues...please help!!

I am concerned that this porpoising is so severe that there is actually something wrong. There is already a lot of weight up front. I am not thinking prop either. My guess is that tabs will allow you to trim out and make a somewhat major improvement in top speed as you are not able to trim out at all now. I am also wondering how the 90 Suzuki compares in weight to other motors that might be used on that boat.

Based on my own experience I believe helm adjustable or Smart Tabs can solve this issue. It just seems too far off as it is to dismiss other stuff. Just because it is new and of a decent make doesn't mean that this particular hull is right. I'd put a straight edge on it tomorrow if it were me. and just eliminate that as a potential cause. Takes about all of three minutes . . .

 

[tashasdaddy]

Re: New boat handling issues...please help!!

agree with QC, everyone makes a mistake.

http://www.godfreymarine.com/index_polarkraft.cfm

try contact these guys, should be warranty service.

 

[tashasdaddy]

Re: New boat handling issues...please help!!

did a little more investigating. nice boat. rated for a 140hp max engine weight 470lbs, you've got 90 hp, weighs 427 lbs. you might be tail heavy for the hp.

 

[RubberFrog]

Re: New boat handling issues...please help!!

I think daddy-O is on to something. I'll bet you don't have enough power to get over the weight properly.

Tabs will help, but the ultimate solution is a lighter motor or more ponies.

 

[QC]

Re: New boat handling issues...please help!!

teamboy,

I assumed from your original post that this was a problem at most speeds on plane. Is that true? If she porpoises at less than WOT, then I am not sure how it could be about horsepower . . .

 

[thurps]

Re: New boat handling issues...please help!!

I would beg, barrow or steal another prop and run it before anything else except checking for a hook. 1k RPM is a lot if your HP is marginal.

 

[QC]

Re: New boat handling issues...please help!!

BTW, I messed up. I meant a rocker, not a hook. I believe rocker (convex) is more commonly associated with porpoising . . . Doh!

 

[teamclose]

Re: New boat handling issues...please help!!

Thanks for the input guys. I was just in touch with Polar Kraft and they are going to fix the boat at their expense. From my phone conversation w/ PK they weren't worried about weight or anything, and seemed to think adding a bead of weld on each side where the transom meets the bottom of the boat would fix the problem. He was going to get everything run through engineering, but assured me they would make me happy with the boat!

 

[QC]

Re: New boat handling issues...please help!!

Kewl. Get tabs anyway You won't be sorry.

 

[steelespike]

Re: New boat handling issues...please help!!

Let us know what happens.