18ft bass boat porpuses will hydofoil help?

tajjf1

Cadet
Joined
Aug 5, 2009
Messages
13
Hello everyone I have a 18ft bass boat with a 200 johnson on it. As soon as I get it up on a plane it starts bounceing up and down like crazy. I played with the trim with no luck. So from what Ive been reading I think its from too much weaght in the stern of the boat. Wich makes since seeing how the boat is rated for a max of 150hp and 30 gallon fuel tank two batteries. So I also read that a hydrofoil will solve the problem for me. But Ive also heard alot of bad talk about hydrofoils. I need this boat to ride better. Can anyone give me some good advise on this?
 
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Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 18ft bass boat porpuses will hydofoil help?

Hydrofoils, the ones that attach to the cavitation plate of the engine, are mainly to help get the rig up on plane quickly.

Sounds to me like the rig is becoming airborne.
 

Boss Hawg

Lieutenant
Joined
Apr 9, 2009
Messages
1,433
Re: 18ft bass boat porpuses will hydofoil help?

200hp on a boat rated for a 150 :confused:
I would advise you get a smaller motor :rolleyes:
 

Splat

Lieutenant
Joined
Jul 20, 2008
Messages
1,366
Re: 18ft bass boat porpuses will hydofoil help?

Imo smart tabs would be a better choice to eliminate porposing.

A dole fin may work, but may make theproblem much worse.

Bill
 

nlain

Commander
Joined
Nov 17, 2005
Messages
2,445
Re: 18ft bass boat porpuses will hydofoil help?

Smart Tabs, go here and look; http://www.nauticusinc.com/ , use the phone number at the bottom of the page and call them, they will advise which one you need. Then come back to iboats.com to buy them.
 

doublesharp

Cadet
Joined
Aug 2, 2009
Messages
6
Re: 18ft bass boat porpuses will hydofoil help?

+1 on the Nauticus smart tabs. I put a set on a HydraSport bass boat DV225 20' w/200hp XP and they tamed a bad porpoise problem. I've got a Bob's Marine stabilizer plate, and that helps, but the smart tabs solved the problem.

Easy to install and nothing to wire. Mine are 7-8 years old and the shocks seem as good as new.
 

BWR1953

Admiral
Joined
Jan 23, 2009
Messages
6,278
Re: 18ft bass boat porpuses will hydofoil help?

Your boat is overpowered by at least 33% and you want us to give you advice on how to make it USE that power?

Replace your 200hp engine with a 150hp motor and see if the problem goes away.
 

HappierWet

Master Chief Petty Officer
Joined
Sep 11, 2008
Messages
839
Re: 18ft bass boat porpuses will hydofoil help?

OK, Let's break it down. As previously noted you are WAY over powered, that could potentially cause you legal issues. But assuming you want to take that risk, let's look at how the boat performs. How does it come out of the hole, does it only porpoise at WOT,or close to it? BTW is there a rod on the mounting bracket that determines how far down the motor will go? What is the diameter and pitch of the prop?
Also, for the sake of safety...because you are so overpowered, be aware that there is insufficient hull to water interface which is creating your fore and aft instability....using a hydrofoil or trim tabs has a very high probability of making a bad situation worse.
You can probably make it safer with some trial and error, but it won't be anymore legal.
HW
 

tajjf1

Cadet
Joined
Aug 5, 2009
Messages
13
Re: 18ft bass boat porpuses will hydofoil help?

Thanks guys I guess im going to fix up the 115 johnson i got and buy something bigger for the 200 Im gonna try a cheap hydrofoil for the heck of it untill i can get them swapped Ill be carefull on the water though always do.;)
 

Boss Hawg

Lieutenant
Joined
Apr 9, 2009
Messages
1,433
Re: 18ft bass boat porpuses will hydofoil help?

Thanks guys I guess im going to fix up the 115 johnson i got and buy something bigger for the 200 Im gonna try a cheap hydrofoil for the heck of it untill i can get them swapped Ill be carefull on the water though always do.;)

Yeah- my wifes going to trim her beard soon too :rolleyes: :D
Just be carefull :cool:
 

mrcj001

Petty Officer 1st Class
Joined
Jul 25, 2008
Messages
313
Re: 18ft bass boat porpuses will hydofoil help?

My Cajun was rated for a 70HP...it now has a 135HP...mine was porposing too. The trim tabs solved the problem immediatly. Planes and runs like a champ.
As far as legal issues with a overpowered boat...get liability insurance and tell your agent that the boat is over powered...(dont lie about the engine size) and you should have no problems.
 

HappierWet

Master Chief Petty Officer
Joined
Sep 11, 2008
Messages
839
Re: 18ft bass boat porpuses will hydofoil help?

My Cajun was rated for a 70HP...it now has a 135HP...mine was porposing too. The trim tabs solved the problem immediatly. Planes and runs like a champ.
As far as legal issues with a overpowered boat...get liability insurance and tell your agent that the boat is over powered...(dont lie about the engine size) and you should have no problems.

Although it's never happened to me, I believe you can be cited for overpowering.
 

SeanT

Senior Chief Petty Officer
Joined
Jul 8, 2009
Messages
661
Re: 18ft bass boat porpuses will hydofoil help?

I've seen too many 16' runabouts and skiboats with 140+ HP engines (lots of outboards, with the model obviously visible). I've heard that overpowering is illegal as well, but I don't think anyone ever gets taken to task on it.
 
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