Bouncy Boat !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

[BarryBum]

I am new to this whole boating thing so please forgive me for asking so many dumb questions. I have posted a few posts earlier about slow planing and throttle response woes. Now I have another dumb question. When my boat does decide to run good and strong, the nose bounces an awful lot. It seems to bounce up and down a lot and splashes the nose hard everytime it dips. Could my engine depth in the water be causing this? I have n 87 Cimarron walk thru windshield 15 footer with a 100HP Johnson. Currently it is all the way down as far as it will go. My other posts has to deal with prop size. Any thoughts on any questions I have are appreciated.<br />Thanks

 

[Yepblaze]

Re: Bouncy Boat !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

Are you sure you can't kick the motor drive inwards toward the boat anymore? There may be an additional stop that is adjustable, or the linit switch may be adjustable, or you may not have found that you may have another set of switches for the trim in addition to the tilt. (just guessing here)<br /><br />If not you are going to have to move some weight forward, and or you might try one of those fins that attach to the horizontal plate above the propeller.

 

[Bear]

Re: Bouncy Boat !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

Yepblaze,<br />Isn't it just the opposite? Doesn't the boat overplane (maybe not the right word). My suggestion is to tilt out and move weight backwards. That phenomenon appears often on a short boat with too much power and at WOT.<br />Maybe I'm wrong.

 

[Yepblaze]

Re: Bouncy Boat !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

Haven't heard of that one. Gee, I don't know.

 

[SS MAYFLOAT]

Re: Bouncy Boat !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

Short boats and big motors is like the fine line between being a genius and stupidity. Try making small adjustments. Had a 14 footer once with a 90hp. Ended up putting a hydrofoil on the cavatation plate and added trim tabs. Water and Wind Currents made me constantly use the trim tabs. They are alot of fun but trickly if you don't know what your doing. Yepblaze and Bear are both right. While the drive is out to far, it will cause the backend of the boat to outrun the front end, simular to a wheelie in a drag car. If it is in to far the drive is going to try to drive the bow of the boat into the water, once the bow of the boat is too far in the water, then the bouyancy of the water takes over and throws the bow up into the air causing your bouncing...Be careful small boats with big engines can get away from you. Happened to mine after having it for 3 years. Thought I knew everthing about it. NOT! Good Luck....SS

 

[manowar]

Re: Bouncy Boat !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

measure your transom then measure from the fin up to the bottom of the cowl your in to deep or not enough if the measurements way off

 

[manowar]

Re: Bouncy Boat !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

I just remembered the fin you can add if the boat rises more than you think it otta when starting out the addition of a fin could solve all the problems . I would see if the motor is rated for your boat and consult a service tech for prop and anyother mismatches

 

[StringBox]

Re: Bouncy Boat !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

Had a similiar problem. I bought a stingray hydrofoil. Stopped the problem cold. There are lots <br />of brands. Doel fin etc... The stingray was $37 bucks at boaters world. I think the Doel Fin is about $20. From what I have read, either one with do a good job. <br /><br />My boat handles better, comes up on a plain faster but I lost about 3mph top end. You've got plenty of motor so I don't think loosing a couple of mile per hour will be a big deal for you.<br /><br />You must drill four holes in the cavitation plate to bolt up the hydrofoil. Took me about ten minutes and I was off to the water for a test run.

 

[SB]

Re: Bouncy Boat !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

I have a 14 foot Bayliner sport jet 90 and had a problem porpoising also. I solved it by installing Nauticus trim tabs. These work great. They stopped the porpoising and helped the handling. They cost about $150 but were worth it. The owner of Nauticus if very helpful. I had an unusual mounting arrangement and he worked with me until it was resolved. They did take about 2 mph off the top end however.<br /><br />Scott

 

[seabass]

Re: Bouncy Boat !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

hydrofoils such as doel fins work excellent and most of the times are an inexpensive solution.

 

[Squeakit]

Re: Bouncy Boat !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

Amen to the Stingray Hydrofoil Stabilizer! I have a 15 foot Bayliner with a 50 Force and even though I lost about 5mph on top speed the boat is solid as a rock now. I'd rather go slower and not have to throttle back every time there is a wake or a swell to cross. Just like a shock absorber - boat is glued to the water. If you put one on, you'll have to run your trim higher, but with all the power you have you won't lose a thing.

 

[what200]

Re: Bouncy Boat !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

Another thing to try would be to raise the height of the motor on the transom. This can happen if the prop is ran low enough below the bottom of the boat that it has enough leverage to lift the front of the boat. But as the bow rises the prop loses enough trust to hold it there and the bow falls. If it falls enough the bow hitting the water will exxagerate the problem. Negative trim will usually solve the problem but with a loss of speed. Raising the motor reduces the amount of leverage and can improve the problem. Try going up one hole, but just make sure the motor is getting enough water as you go up.

 

[Pro Crappie Guide]

Re: Bouncy Boat !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

Pull your low end trim pin out and leave it out and try running it that way.<br /><br />The motor will not hop if the motor is trimmed down too low,

 

[Forktail]

Re: Bouncy Boat !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

Any 15' boat, especially with 100 hp, is going to be weight distribution critical. You can do all kinds of things to the outboard, but unless the boat is balanced with weight properly you won't solve the complete problem. Try moving weight forward.