Author Topic: New minimax with a long shaft outboard motor?  (Read 268 times)


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New minimax with a long shaft outboard motor?
« on: January 23, 2020, 10:05:09 AM »
In december 2019 i starting building my first minimax:

Last week i found a nice 15hp outboard motor, but it is a long shaft. It's weights about 88 pounds (40 kg).

Which changes would you suggest to the minimax to fit a long shaft motor?

Obliviously the motor board should be higher  :-) But are there any more changes i should make?


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Re: New minimax with a long shaft outboard motor?
« Reply #1 on: January 24, 2020, 04:39:13 AM »
I also went with a long shaft motor on my XL and added height to my transom . My motor weighed in at just about 200 lbs FYI.

58 Johnson

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Re: New minimax with a long shaft outboard motor?
« Reply #2 on: January 25, 2020, 08:24:41 PM »
Hi olfellow!  And welcome to the site.

Putting a long shaft motor on a sea flea is not a common occurrence but the question is asked often enough that we, collectively, as boat builders should have a pat answer!  But alas, we don’t.  Welcome to the world of boat building!   :wink:

I’ve never built a Minimax myself, but I know they were designed for short shaft motors, which were the most common length when the boat was designed 65 or so years ago.

So... while I still hope that people with more experience either with the added height and/or with putting larger motors on a Minimax will chime in, my advice is to make sure, at least, that the coamings match the new motor board. 

My personal preference would be to add a transom knee.  It’s not in the original plans, but I’ve seen pictures of them added successfully.  You should be able to find pictures, but if nothing else, check out the MiniMOST plans for a visual!

If your 15 is a a newer one, it’ll have a kick to it, and you don’t want the motor board flexing! 

That’s my two cents.   Other thoughts out there?
Ross Jewiss, Huntsville, Ontario


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Re: New minimax with a long shaft outboard motor?
« Reply #3 on: January 25, 2020, 09:33:38 PM »
Before you modify the hull, can the motor be modified.  Many of the smaller long shaft motors have and extension in the leg with a longer drive shaft.  A short shaft subsition and removal of the extension may result in a short motor.

If not, the transome extension needs to be well reinforced.  If you will be adding steering this could be an engineering challenge.

I've never tried a long shaft on a minmax, but then I have done other things to these little hulls that I was advised not to do,

So, without holding your beer, let's see what happens.