planeing problem question

[edthearcher]

about a month ago I purchased a 1990 javelin bass boat, made by stratos, 16 foot with a 140 evinrude motor previous owner who had only owned it since last march, said he didnt believe it was the orignal motor, the boat is a 1990 and the motor is a 1986, I asked him what was the pitch on the prop, he wasent sure its a SS riker I believe. any way a neighbor told me to get rid of the add on plastic tab that is bolted to the motor. the first time I took it out it jumped right out of the water and planed off really good, o.k. I say to my self I unbolted the plastic planing device, took it out and the boat wanted to tip over backwards. had to have the wife set on the foward casting platform to get it to plane. well you know what it did to her rear end when I hit the first wave. so I put it back on, the motor was all the way down, and I tried diffrent angles still no good , any advice thanks ED

 

[rndn]

Re: planeing problem question

I know people talk bad about hydrofoils but I had very good luck with one. I think in the right application they will work fine. I know trim tabs are better, but for the price and performance sometimes they will work just fine. I had put one on my 89 Baja Force 216. With a heavy 5.7 in the rear of a 20 foot boat it was very transom heavy. Could not plane without asking people to get into the front area. A hydrofoil almost eliminated that and then with the addition of a four blade SS the boat actually launched out of the water.

 

[tashasdaddy]

Re: planeing problem question

i've had good and bad experiences with the hydrofoil, mostly bad. the # 1 reason i recommend smart tabs, is that they put the force and strain on the boat in the proper place. at the bottom of the transom. use foils, you are putting the lifting strain, and force on the motor, which transfers it to the motor mount at the top of the transom. thus you are putting stress on the boats transom, it really was not designed to take.

 

[Chris1956]

Re: planeing problem question

Ed, It sounds like that boat sits very low in the back. Perhaps the boat is not rated for that heavy of a motor?

Anyway, You should not need a whale tail or smart tabs on that boat. You want to carry the bow for highest performance. Whale tails and tabs are counter to carrying the bow.

I would think the motor may be mounted too low on the transom. Where is the Antiventilation plate in relation to the bottom of the hull? The A-V plate should be 1/2" above the bottom of the hull, at least, especially with that high performance prop. Make sure you are trimmed IN all the way when you try to get on plane. Trim out after you are on plane, until the steering is light.

 

[Texasmark]

Re: planeing problem question

The '98 Javelin catalog lists a Model 350A at 15'3 rated for 70 hp. Next is a 369 at 16'8 rated for 130 hp. Then there is the 379 at 17'9 rated for 150.

Getting the idea. Looks like Chris nailed it......overpowered.

Mark

 

[edthearcher]

Re: planeing problem question

chris you bring up a question I was going to bring up at a later date. but Ill try to explain the best I can. the anti ventlation plate which I would call the planeing fin on the motor. o.k. now let me try and explain if you look at my transom it comes down than is resised in about 2 inches to where the drain plug is located and also the drains for the live wells. yes it is very stern heavy 20 gal gas tank in the rear 2 battries, a 140 hp motor I believe the orignal was a 125 plus a 2 gal oil injection tank, plus 2 people but there must be an answer Iam sure stratos wouldnt let it out the door if it was unsafe would they

 

[j_martin]

Re: planeing problem question

A bass bote is designed with most of the weight in it between the driver and the transom, because for all out speed with the nose in the air so you don't take a shower everytime you hit a little wave, that's where you want it.

To get one to take off, you need to tuck the motor down, even to a negative angle to get that heavy rear end up on plane. The neg is, if you run the motor there at full tilt, and turn the steering just a little bit, it'll hook so hard it'll pitch you out of the boat. For that reason, most mechs set it up for a new user with a stop pin to prevent the engine from being tucked fully under.

If that lower trim stop is there, take it out. Tuck the engine fully in and blast off. Get on the trim immediately as you gain speed, and it'll trim out, lift the bow, and fly like it's supposed to.

If it still wants to do a transom stand, maybe your engine is too low on the transom. If set right, the prop should be just barely under the surface when it's running full speed. Some props even like to pierce the surface a little bit. The limit on stock engine setup is usually getting enough cooling water into the engine.

Oh, and get rid of the damned whale tail before you break something.

hope it helps
John

 

[Willyclay]

Re: planeing problem question

I don't think the WEIGHT of your motor is an issue because all the OMC V4's weighed about the same regardless of HP. The 140HP may be a different issue (insurance & liability) depending upon what the boat was rated for maximum. The experts on this forum will steer you straight. Good luck!

 

[edthearcher]

Re: planeing problem question

I think j martin might have hit it on the head, any way boat is put away for the winter Iam going to copy thease replys and take them to my marina next spring thanks again ED

 

[edthearcher]

Re: planeing problem question

any other input would be great, because next april all thease notes go to the dealer you guys sure no your boats thanks ED

 

[QC]

Re: planeing problem question

I'm TOTALLY with j martin with the addtion that after his suggestions you should set her up so that she will just slightly porpoise at full speed and full out trim, then control that porpoising with some type of dynamic (movable) trim tabs. These will also improve your hole shot and bow rise.

 

[SpinnerBait_Nut]

Re: planeing problem question

chris you bring up a question I was going to bring up at a later date. but Ill try to explain the best I can. the anti ventlation plate which I would call the planeing fin on the motor. o.k. now let me try and explain if you look at my transom it comes down than is resised in about 2 inches to where the drain plug is located and also the drains for the live wells. yes it is very stern heavy 20 gal gas tank in the rear 2 battries, a 140 hp motor I believe the orignal was a 125 plus a 2 gal oil injection tank, plus 2 people but there must be an answer Iam sure stratos wouldnt let it out the door if it was unsafe would they

And I'm sure they did not let it out the door with a 140 on it.
Check the CG plate and see what it's rated for.
With that said, if you are not getting the motor tucked all the way in at take off, it will stand up like that and stay there if you don't have enough power to bring it out of it.
Also if they start moving it up any, make sure they don't get it up so high that it will loose water pick-up at speed.
You will be buying new powerhead in an instant.
I have jack plate and a Bob's LWPU and I can bring mine way up to get in that skinny water.

 

[keamburgey]

Re: planeing problem question

I have the javelin 350a This is a 15.3' boat but most people say that it is 16' This sounds like what you have. If this is the case it is only rated for a 70hp max hp outboard. They will not handel the weight of a lager motor. They are rated to have 800lbs with motor gear and passengers.

 

[Bondo]

Re: planeing problem question

I have the javelin 350a This is a 15.3' boat but most people say that it is 16' This sounds like what you have. If this is the case it is only rated for a 70hp max hp outboard. They will not handel the weight of a lager motor. They are rated to have 800lbs with motor gear and passengers.

October 18th, 2007

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