Transom modifcation

[RobD]

Hi I'm new to the forum,my name is Rob,Im live in Florida,I just bought a new old pontoon 1981 90 Hp mercury,Ive been redoing most of the boat.Put new floor in,rug,radio,steering,shifting ,Throttle cables,resealed lower unit,now Im pretty much done with what I can do cosmetically.I took my wife and Daughter out on it the other day and it runs like a dream,beside it has no trim and tilt,The pontoon draws 26inches of water at Idle,I tried raising the motor to max height but it cavitatis.It has a box type transom that tappers toward the front of the boat.The deepest part of the transom is 14 inches.I was wondering if I could remove the rivets that connect the tapping box to a angle bracket that connects to the cross members of the boat,and cut about 4 inches off the top of the box, which will still leave the transom 3 inches in the water.so I can raise the motor up a little more?Or possibly would anyone no were I can get a shallower box transom.Thank you in advance for any info.

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[margaritaman]

Your motor is sitting high from the picture. You need to lower it so the top cavitation plate is even with the bottom of the transom.

[lakerunner]

Your cavitation plate is just below the bottom of transom it looks like so your good there. If your drawing that much water you might check if water is in logs. Might also move some weight up front to level the load a bit.

[RobD]

Thanks for all the info,what I'd like to do is make it run as shallow as possible.most of my fishing spots are about 3-4 ft on high tide,I can get into them with my Bass boat,but now I have this pontoon I,d like to get in them with it,My wife and 2 year old daughter, will stay out all day on the pontoon ,because the canopy, radio, grill,and much more roomy.
So basically how much of the bottom of the transom box has to be submerged in the water,with out having repercussions.

[lakerunner]

I think the safest and easiest thing to do is find a tilt & trim for your motor. There are aftermarket ones out there and some better than others.
I can't see messing with transom in going to give you more clearance. You have to have the cavitation plate at or slightly below the bottom of transom.
Another thing you might find a power jackplate to raise motor when in shallow water.

Bottom line is this ain't no bass boat and will never get in places the will.

[BassFrequency]

Bottom line is this ain't no bass boat and will never get in places the will.

I wouldnt go as far to say that LR I can get and manuver my girl in as little as 1.5' of water with slight tilt. so its possible.

I cant quite see what could cause cavication from what i can see in your pics.

it may just be the angle of the pic but it kinda looks like the rear splash panels on the sides of the motor pod are sagging a bit

have you tried a hydrofoil yet?

thats about all I can think of at the moment

[RobD]

brought it down to local aluminum welder,he said he would cut 4 inches shorter and reinforce it,4 $100.00,said that he has done it on a lot of pontoons,said as long as the transom sits in the water 1 1/2 inches I will not have any problems,so I should be fine I still have 3 inches submerged after he's done. Will have it back tomorrow,and let ya know how it works out.

[BassFrequency]

wow, he gave you a good rate for that labor 2 years ago i got reamed $500 to fix a leaking M bracket and leaking logs

[RobD]

Ive know him for a long time,and he's done a lot of work for me already.

[RobD]

got her back,Took It for a test spin,Runs 4 mph faster from 21- 25 mph,must have took a alot of trag out. Use too get the water running up on gas tank and battery area,now I have none.Still doesn't run a shallow as I'd like but this was a great start.Time to start looking for a Jack plate.Any suggestions..

[LTB Racing]

whats wrong with the power trim?

[RobD]

power trim motor doesn't work,I even tried to hook it up directly,found one on ebay for 185.00 doesn't seem to bad of a price.