bow pushes water

[edboat]

I have a 1985 Edson Avanti Ss 17.5 ft closed bow boat with a 175 evenrude on the back. Right now, when i reach a speed of about 50 mph, it seams like (and looks like) i have to much of the hull in the water. The motor has a limited amount of trim at speed so at full trim this condition still ocurs. It seems to me that getting the front half of the boat out of the water and on plane would give me a better speed due to less resistance. Although when i get to the top speed of 57 mph it chine walks . Any suggestions on getting more of the hull out of the water and preventing chine walk?

 

[Jdeagro]

Re: bow pushes water

You are correct, the boat should be running on the last third at that speed. Something is lifting the stern or weighting the bow down. The boat is also very sensitive to steeriing port to starboard at higher speeds. Look at the motor mounting to see if there is a wedge which allows the motor to be trimmed under more than usual. This is done to make the boat plane easier by triming the prop under more. See if there is a hydrofoil on the motor (plastic wing device on the cavitation plate). My guess is you have a Hydrofoil on the motor.

 

[edboat]

Re: bow pushes water

Thanks for the reply NautiJohn. I do not have a hydrofoil on the cav plate and no wedge on the transom mount. Perhaps i should put a wedge at the bottom of the mount to obtain more trim angle at speed. the gas and oil tank, and battery are all at the back with very little weight at the front due to the closed bow design. i somehow need to get the bow more out of the water at speed. Any other suggestions?

 

[Jdeagro]

Re: bow pushes water

Make sure you are running the motor trim out, and check it in case the fluid is leaking allowing the trim position to change. Does your motor have a rod to adjust the maximum down trim angle. What type of prop are you using? Remember this is aboput balance, look at all of the things in the boat and check the hull for possible hooks near the back. Something is lifting the stern too much when you are on plane.

 

[magster65]

Re: bow pushes water

My brothers 17' Campion did that too. It had a hook in it.

 

[edboat]

Re: bow pushes water

I will check the hull bottom for a hook as this is one item i had not considered. There is a stop bar on the motor mounting bracket to limit the amount the motor can be trimmed down and i will move that bar higher to get more tilt on the motor. The prop is a SS Raker 14 1/4 x 21. i had noticed in other posts that the Evinrude's tilt only goes up so far under power and this is true of mine as well. Apparently the Merc trim can move the prop right out of the water. I don't see any signs of trim oil leaking and the trim gauage does not vary from the position the trim is at. Does a hull "hook" have to be significant to affect performance? i also assume the hook is measured from back of hull to forward with a straight edge?

 

[Jdeagro]

Re: bow pushes water

Yep, use a steight edge fron to back. and the hook could be as little as 1/4 to 3/8". Also depends on how wide it is. Good luck!

 

[Dhadley]

Re: bow pushes water

Are you trimming the motor out (up) after it gets on plane?

 

[edboat]

Re: bow pushes water

Dehadley.....yes i am trimming the motor as high as it will go when i am at speed. The trim /tilt guage indicates the high position. However, it seems the you can only go so high on trim with the OMC setup. I think the Merc setup allows you to continue lifting beyond trim when at speed.<br />I will try moving the stop pin higher on the motor mount for more angle but the trim only has a small range to work with. can only go into tilt mode when running a very low speed.<br />Thanks