Outboard Platform or Cut-down Transom?

[CarbonFootprint]

Hi,

thanks for your thoughts.

The all up weight of the inboard and sterndrive was approx 300KG - I'll almost certainly be going for a 2-stroke motor of about 100hp, approx 150KG, so there'll be an appreciable weight-saving, but a dramatic weight shift aft. This boat was originally designed for an outboard and the transom is reinforced to take one, so I could go for a normal transom-mount setup, but I've been told that an extension is a better option...

Integrating the extension into the hull is my main concern - I don't want to weaken the hull by cutting into it too much, but I would imagine I'd end up grinding the GRP down and then re-laminating a good meter or so to integrate the extension properly...



...the extension section itself would be bolted through the existing transom using stainless steel brackets and would be properly sealed.

Pre-fabricated brackets seem disproportionately expensive to me and there's very little information on them in the UK - they're also not very aesthetically pleasing from what I've seen, being just a box you bolt onto the transom...any additional info would be gratefully received, though

Thanks again,

Paul

[Ike]

I was thinking more along the lines of a Gil bracket. It's not a box. rather it is made of steel or aluminum tubing. It's open so i won't add any buoyancy, but it's lighter than a box and many of them allow you to adjust the height of the motor.

[CarbonFootprint]

A Gill Bracket is another new one to me :



This seems like quite a good resource, actually:

http://continuouswave.com/whaler/ref...eBrackets.html

Trust OMC to come up with something weird... I'm definitely thinking along the lines of the "moulded-on bracket" - what would the effect of the step in the one on this page be?

Thanks,

Paul

[Ike]

Actually the Gil bracket has been around since i was a kid, and I won't tell you how long that's been! I can remember people putting gil brackets on boats in the 60's and 70's. back then they weren't painted or anodized. they were bare aluminum or stainless steel, but the concept hasn't changed. It moves the engine back putting the prop in cleaner water, moves the LCG farther aft which makes the boat run flatter (counter intuitive but it works) Most of them are adjustable so you can move the engine up and down. they are lighter and easier to install than a hull extension. and they transmit less noise and vibration to the boat.