Raising engine on transom

[tue]

Having removed the engine to aid in the fibreglassing of the floor I was contemplateing raising the engine up a hole or two when I re-fit it. I have checked out the Mariner rigging guide and it suggests I can raise the engine anything up to 5" above standard (cav plate level with hull). Obviously I don't want to go anywhere near that high. Then general rule tends to be 1" for every 10mph over 40mph. I was thinking of starting at 2 holes up (with no hydrofoils) to try and if necessary go down 1 hole.

My only concern is any difference between when I have divers on board and not. Anybody had experience of a jacked up engine used with alot of weight on board?

[jwalker]

Just do it and find out for yourself.

[Pete7]

Tue in addition to raising by 150 V6 Mariner on my Ribtec I put the engine back on the centre line after Ribtec mounted way off centre. This didn't alter the handling but it meant the boat came up on the trailer level.

Pete

[Turbodiesel]

I would try lifting it by one hole, i have just rigged a Ribcraft 5.85 with a Mariner 115 four stroke, ended up lifting it by two holes.
Its great when the boat has a load in it but when its running light it cavitates alot in turns which is not so good.
I have set it up to be at Seawork next week were it will be taking people out for rides so its ok. When it gets back im going to put it down one hole.
Pete7 im suprised it didnt make a difference puting the engine in the center, but it does depend on boat size and what the hull shape is like. Deep V hulls like Seariders need lots of offset were as wider hulls dont need much off set.

[Ian Austin]

A coulpe of years ago a customer pulled the bolts part way through the transom of his boat, it was a 17 ft speed boat with a 200hp black max on it, i made an inner and outer transom plate from 3 mm stainless and put the engine back on dead center, he came back a couple of days latter and said it had transformed the boat for the better, could never under stand why they offset the engines, if it is because of prop torque then altering the trim fin should counter act this, that is what i did to this boat.

[Pete7]

Originally Posted by Turbodiesel

Pete7 im suprised it didnt make a difference puting the engine in the center, but it does depend on boat size and what the hull shape is like. Deep V hulls like Seariders need lots of offset were as wider hulls dont need much off set.

Yup, couldn't feel any difference, might have been because the 6.45 hull is quite long and deep V therefore tended to fly and land straight.

However it did take alot of power to move it and wasn't quick. Prefer a warped V shape as an all round hull form like Scorpion (or BWM)

P