transom height question

KJM

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Joined
Jul 31, 2016
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1,271
Hi, i am planning on doing a conversion from i/o to outboard. I was planning on a 20 inch transom height for a long shaft motor. When i measure 20 inches up from the lowest point at the center of the existing transom, 20 inches is right at the waterline. I do plan on building a enclosed well around the outboard cut up to the top of the existing transom, but the outboard would be mounted right at the waterline? Should the waterline be lower if the boat sits higher due to losing the weight of the old engine and drive? Is it ok for the outboard to be that low to the water or would it get flooded by water from the wake?
 

JASinIL2006

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Feb 10, 2012
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5,729
Can't help you, but it sounds like an ambitious project! I'm sure someone will be along who's done this...
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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not sure what you are specifically working on.....

however since are working on an older boat that had an I/O and now you are going to a pod to run outboard or outboards, normally they are set back a fair amount and most are running 25" long shafts

the set back allows you to raise the pod a bit and ultimately raise the props a bit

the weight and location of the pod and outboard are aft of the transom, so the boat will sit lower in the water at the transom , even though total weight may be less than an outdrive and motor 3 feet in front of the transom, as you move the weight aft of the transom, you have a greater lever arm pushing the transom down.

many "professional" companies have issues doing a conversion. nearly all the ones documented on iboats that I know of have had issues or never get completed.

here is a long list of conversions attempted on iboats

https://www.google.com/search?clien...hUKEwjjt6CL7IvqAhUimeAKHZD0DWkQ4dUDCAs&uact=5

my recommendation would be to call companies that specialize in conversions and ask them questions.
 

Bondo

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Apr 17, 2002
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Ayuh,....... Go with a 25" motor,......
 

KJM

Lieutenant
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Jul 31, 2016
Messages
1,271
Thanks scot for the info, but i'm not going with a pod. just putting the motor straight on the transom. I would like to go with a 25 inch leg motor, but i will be buying a fairly new used and most of them i think are 20 inch. Maybe i'll start cutting down to 25 and see from there how she floats. How close to the water is the engine usually sitting on an outboard boat.
 
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