Anti cavitation plate height, should I cut transom

[ezmobee]

Re: Anti cavitation plate height, should I cut transom

Cut your losses and sell it. Old mercs and old fiberglass boats are not for folks new to boating.
Having a reliable boat/motor/trailer that you can fish out of and pull a tube with multiple passengers is not an inexpensive venture.
If you have no skills at working on boats/outboards, you really want something relatively new. A qualified mechanic costs too much to make repairing an outboard that old worth it.

Harsh though it might be, this post is 100% correct. We don't even have to get into the fact that there's about a 98.5% that this boat has a rotted transom. If you want to get on the water cheaply, look for an aluminum hull and an outboard that's well supported with parts.

 

[colbyt]

Re: Anti cavitation plate height, should I cut transom

My thought on it now is that I know that it runs great at idle speed so it will still work great as a fishing boat. Hopefully by this time next year I can buy the kit to make it a 20 inch motor and see It's potential. At least we have a boat that floats and moves. Baby steps, baby steps...lol

Great attitude.

After looking at you images I would strongly discourage you from trying to cut the transom. After you get the tilt set right it may run better than you think.

What part of KY? I'm in Lexington.

 

[Sea Rider]

Re: Anti cavitation plate height, should I cut transom

Some issues :

1-Being an old boat you can't supposedly affirm the fact that it has already a rotten transom, probably used once in a while and in mint transom conditions, drill a hole and check if with moisture, or whatever destroys fiberglass transoms. If you could get the previous owners boat's history much better.

2-That boat is rated for a 65 HP engine, so a 35 HP is a light engine. If transom has not have any issues so far, probably won't in near future.

3-Assume that at most, transom must be chooped 2" down, which will not alter the structure of the original boat's transom as the transom angle will remain same.

4-In case you chop transom down, don't need to chop all transom's lenght, just chop down the width of the engine. If you chop transom dowm more than 2.5" upper pan could come to a stop when steering fully sideways, due to not having sufficient clearance between pan and swivel bracket at turns. In that case will need to round both lateral 90? side cuts as required.

5-If the boat is not tested under trial with a spotter as stated, you'll never know how much you need to chop that transom down and will be eternally wild guessing.

6-With a short shaft 15" engine mounted on a 20" transom, you should experiment something like this at plane & straight water courses with engine perpendicular to sea level and boat riding paralell to water surface.

-Lightly exposed anticav plate, engine peeing well, cavitation, aireation at close turns, in this same example there's a 2" height difference between upper deflector and anticav plate.

7-At $ 200 for the boat engine and trailler wouldn't you want to fix it right for the kids and crew to much enjoy going from boring idle to full plane. It's like hearing a single violinist, much better the whole quartet.

Check this proper engine/transom height & trim video to get right the overall idea:

http://www.youtube.com/watch?v=oBeZjaA76VM&feature=youtu.be

Happy Boating

 

[coolbri70]

Re: Anti cavitation plate height, should I cut transom

here's a video of a short shaft on a 20" transom, it will move the boat but not plane

i would expect similar performance

 

[Sea Rider]

Re: Anti cavitation plate height, should I cut transom

That horse is used as an aux to move a heavy old lump, if placed at middle transom it's pushing performance would be probably much better. Use to have an Evi 9.9 in order to pass it to a full 15 HP appart from carb swap, you'll need to change complete reed valve assembly which has slight bigger orifices in order to let more gas in delivered by the bigger 15 HP carb. At that time about $ 300 conversion for carb, reed valve assy and gaskets.

Happy Boating

 

[64osby]

Re: Anti cavitation plate height, should I cut transom

Could a jack plate be used to lower the motor? Could be a possible homemade solution.

Post a C/L want to trade for a long shaft ad. You never know what may happen.

 

[Sea Rider]

Re: Anti cavitation plate height, should I cut transom

Probably too complicated, the boats uses a pully steering old system which will need to be re arranged including both gear and throttle cables if installing a exterior jack plate. If needed after the water test, a transom chop down would be the most fastest and cost effective work if planing to stay with actual horse...

Happy Boating