boat bouncing

[Mr4am]

I have a 19' Alumaweld super Vee. When I get up on plain the front of my boat bounces in the water. I had the back edge of the bottom of the boat bent slightly (there suggestion)I thought to keep this bouncing from happening. Any suggestion? I've also tried trimming the motor after I get up on plain butI dont see/hear any differance in how my boat performs. Mr4am

[Reelentless]

Trim tabs really help reduce porpoising.

[jimh]

Another vote for trim tabs! This may be obvious, you can try redistributing the weight, and I've heard that on some boats a heavy anchor up front takes care of it.

[fishdog]

I have 19' Alumaweld Stryker. I put a Doel-fin on my motor. Have no porpoising and ride's sooth in chop. The only way to go. :smile:

Good fishin: fishdog :cheers:

[Mikeymoto]

Jet or prop?
MM

[Mr4am]

Its got a prop.

[WaterDog]

Do you have power trim? You should be able to trim the hop out of it.

And I agree trim tabs are worth looking into as well.

[judyfish99]

I drove an Alumaweld out to Buoy 10 last year. it did a lot of bouncing, too. Came down hard on the chop and hurt my back(the first time)ouch!. Check into doel-fins. A doel-fin is on my boat and makes the ride much better and it is on plane quicker. Just eyeball them to make sure that they are in good condition.. :hearton: judyfish99

[Boatdog]

I have an Alumaweld that will porpoise when the motor is trimmed up too far.

When running, I'll trim it up a little, then there is a noticable sound change, and a resulting 2mph increase in velocity. If it's bumpy or I trim up too far, the porpoising starts. Trim down, it goes away.

I wonder if the motor is adjusted properly in the "fully trimmed down" position. :shrug:

[Mr4am]

New boat owner here. Are trim tabs the fins that go on both sides of your motor? Are doel fins the same thing?
Boat dog, I've tried trimming the motor while on plain and cant hear any difference. Hmmm??

[Lured In]

Mr4am...does it still 'bounce' when you have the motor is fully trimmed down (toward the transom)? If so, you might ask Alumaweld about adjusting the motor height in relation to the bottom of the boat. With a properly installed motor, you should be able to adjust the trim for varying weight loads in the boat. I would definitely take the advice and put a dolephin (or similar) on your motor. You should notice an immediate improvement in performance. It may also help to 'grab' more water and improve trim control.

Boatdog...there is no 'answer' to your question about 'proper trim' position. It depends on water condition, weight distribution in the boat and relative speed over the water. An 'under trimmed' boat will porpoise. If you over trim you can end up with the boat 'chine steering' (very bad :wink:). Over trimming will also increase the resistance in the wheel or tiller when turning. :wink:

[5 for Fighting]

I have a 20' Lt with a 150hp pump. Every time I'm running I get the bounce. I keep the tank full, which helps a little and with 2 or 3 people up front it goes away. But it bugs me. Should I bring it back down there and have them look at the motor or do some other mods? I've asked a few people and they say I'll have to live with it. Thoughts?

[Bendman]

I am guessing that a boat of that size is powered with at least a 75 horse power motor. That being the case it should have power trim on the motor. If you trim the motor all the way down and it still porpoises than something needs to be adjusted . You should be able to trim the motor up so the boat will start porpoising on it’s own. To get the maximum rpm’s out of your motor, trim it up just to the point to where is almost porposing. Have you had someone watch your motor when you try and trip it up or down when your on plane? If your trimming isn’t changing the ride in any way than it’s probably not working properly. There is a safety feature on my motor that does not allow me to trim my motor up very much with the
rpm ’s up. Maybe yours is stopping trim all together with the rpm's up. :shrug:

[timinthegorge]

I had a doel fin installed when I bought my 19' Stryker (on the suggestion of friends) and I'd recommend it. You'll get out of the hole faster, and the power trim on my 90 works great to raise or lower the bow in varying conditions and speeds.

IMHO, if the doel fin doesn't work, then power trim tabs should solve the problem... Best of luck with it..... :smile:

[timinthegorge]

Mr.4am..... "trim tabs" are power trim units installed on the bottom of the transom on either side of the motor. A doel fin is installed on the main motor itself. :cheers:

[casteal]

After Fifty years of boating I have to comment. Stabilizers and cavitation plate extenders all do the same thing, Slow you down and use gas. Why don’t you through your sea anchor over, it will solve your problem too.

Load your boat rite, and use your power trim. Does the amount of gas make a difference? Is your motor mounted with the cavitation plate near even with the bottom? Some dealers do it rite, some like to sell you a few hundred dollars of junk.

[Keta]

If you put a "Wing" (as in Dol Fin) on your cavatation plate make sure you inspect it and the plate EVERY TIME you launch the boat. They can break and flip your boat. They do work but your problem sounds to me like you have raised the motor (trimed) too high.

[trap50]

Trim tabs go on the boat,dole fins on the motor.

[5 for Fighting]

I have a 21' 6% Super Vee with a Merc 150hp XR6 pump. I ran my Ranger 481 (bass boat) back in Minnesota for years and I'm well versed in the trim concept. This is my first sled/ pump rig. When I'm solo with the tank full (40 gal) and anchor in the fish box it still bounces. The motor is trimmed all the way down, I have tested bringing it up and the bouncing gets more violent, just like with my other boats. So is it safe to say that the motor may be rigged to high? With 3 other people it gets better but never fully goes away. Any other thoughts? I'm not sure but I think you would need some type of lower unit to add a fin type of thing and I've never heard of trim tabs on a sled. The reason I bought a 6% was for the Clack and smaller rivers, tabs would defeat the propose of a shallow running boat right?

[Keta]

Is the trim stop rod (I don't know the real name for it) set in a high hole?

[rv10pilot]

I agree, the motor is rigged too high.


rv

[5 for Fighting]

It's set to the lowest hole. Do you think this is something the dealer would cover? They did the rigging.

[rv10pilot]

I figure they would cover moving it, especially if it was a new boat. But if it required a jack plate or something like that to get the unit lower you would probably have to buy that. I imagine an inch or so will be all you will need to get the porpoising out.

Have you talked to them about the issue?

rv

[5 for Fighting]

Thanks for all of your help. It will be going in next week for some other stuff and we will talk about this. The boat is a few years old and I've always just thought it was the way it is. Never would have thought it could have been set wrong, they seem to mount 100's of them. I guess I'll know for sure when I bring it in.

Thanks again.

[willierower]

Pull the pin! Ive been running mine without the pin since I got it. My firnd had the same problem with his boat doing the porpoise thing until he removed the pin. Now he cna trim his motor all the way in.

[Fish Wheels]

I had this problem with my hewescraft RR 10 degree. I e-mailed the factory and they advised to bend the bottom tab behind the transom down slightly. I did this with the help of a home made jig for consistency from side to side and it corrected my problem. I still get a little bounce if I trim up to high trying to gain speed, but fixed it for all practical purposes. Not sure if Alumaweld had the built in tab behind the transom or not. Just my .02 .

[Chief_aj]

You should be able to trim the motor back, meaning closer to the boat which will push the bow down. I know I make the bow of my boat go up and down on purpose because the kids get a kick out of it while riding in the front. But I can make it quit by trimming the motor back in. If you keep trimming it up it will get worse. If that doesn't work maybe the weight distribution in your boat if you don't have many people in it may not help either.

[Mr4am]

Fish Wheels, that is exactly what I'm having done. I'm having my 20hour new motor tune up done and I'm having them bend the back tab on my boat. Hopefully that will help. (they said it would).I'll let you know if it works or not. :smile:

[Mr4am]

For anyone interested. I did get the bouncing problem fixed. I had the back tabs on the back bottom of my boat bent. It worked and it runs like a champ!! :dance: :yay: