Change 14ft sailboat to motorboat

Questions about modifying a design

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Joined: Tue Jul 24, 2018 6:07 pm
Location: Victor NY

Change 14ft sailboat to motorboat

Post by BillDez » Sat Mar 30, 2019 4:34 pm

I built a Glen-L 14 foot sailboat back in 2006. It’s a great boat to sail on here in the Finger Lakes of Western New York. But in 2017, I had to have my right shoulder replaced and now I am unable to put up the mast very easily. So I have decided to convert my sailboat to a powerboat.

I have a 4 HP engine on my sailboat and am wondering if I can put a 9.9 HP engine on this boat?

What is the largest HP engine that I can safely put on this boat?

I also will be adding remote steering and engine controls and of course a windshield.

Also, what issues might I encounter when converting my sailboat to a powerboat?

I will many being using this boat on the Finger Lakes and on the Erie Canal here in Western NY.

Thanks for your advice,
Bill Dezen
Victor NY

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Location: Barrie, Ontario

Re: Change 14ft sailboat to motorboat

Post by Cyclone » Sun Mar 31, 2019 5:33 am

I believe the plans say 5hp max. The hull was not designed for more than that so going larger would be a safety issue and the extra weight of a larger motor would be an issue as the stern would not have enough buoyancy for the extra weight (sit low in water). The transom design itself likely would not support the weight structurally nor the force/thrust of 10hp being double the design limit. The forces on the transom when a heavier outboard is mounted during transport on the trailer would also be a concern.

Another consideration not withstanding the other concerns, would be whether the extra power would translate to much increased speed. Larger sailboats have displacement hulls that will not plane, so once there is enough power to reach the maximum hull speed, then adding more power will not increase the speed appreciably. Although it will burn more fuel and put a greater load on the transom. Since your sailboat is small, perhaps it will plane now with the 4hp you have. If it will plane and will run faster then the previously mentioned safety, weight, and force issues become more of a concern as the stability and forces on the transom will increase when encountering any wakes or waves at a higher speed.

I think you would be further ahead by selling you sail boat and getting a boat designed for a larger outboard motor what you want.

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Re: Change 14ft sailboat to motorboat

Post by TomB » Sun Mar 31, 2019 6:56 am


Your modified 14 would be similar to a Fisherman which is rated for 45 hp (although I would go with less). Installation of a motor well would give you an opportunity to reinforce the transom. The aft section of the bottom needs to be flat for and aft if you hope for a planing and predicable ride. Add spray rails!

You'll be adding about 30 lbs off the transom for a 9.9 HP, pulling off ??? lbs of rigging and sails, adding various bits of weight here and there for the new purpose. Locating the fuel tank, battery, even seats, to keep the boat setting on its lines is important but shouldn't be too tough. Keeping the centerboard trunk?

Go for it and post pictures.


Posts: 4
Joined: Tue Jul 24, 2018 6:07 pm
Location: Victor NY

Re: Change 14ft sailboat to motorboat

Post by BillDez » Sun Mar 31, 2019 8:03 am

Thanks for the replies and your comments.

I am planning on removing the centerboard trunk and have when i built the boat as a sailboat covered the back of the stern with a deck. I will post pictures of the boat as a sailboat. See atached

I do not want to plane the boat, but want to go faster than the 4hp. So, maybe i will rethink the weight of the 9.9 motor. I will review the weight of a smaller motor.

I will post pictures as I do the changes to my boat

boat pic.JPG

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