Dory 13 outboard size recommendation

[dajoco]

Hi all, I’m looking for an outboard for my Dory 13. The Dory has a max rating of 50hp. Ideally I want to keep the weight down, as I like to launch from the beach. It’s usually only myself and one other person on the boat for some fishing.

I originally put my 60hp Mariner (about 100+kg) on it to test the boat out, but it sat very deep at the transom in the water. So ideally I’m looking for a smaller lighter outboard that will still get me on the plane.

I understand that it’s very likely that these boats have waterlogged foam floors. I have fitted a couple of bungs and a little water did come out so under no illustrations. I know that it will be wet to some extent and intend to remove the floor and replace it along with new foam at a some point. I’ve done it to other boats in the past.

Any help would be much appreciated

Regards
Dave

 

[jfm]

I wouldn't put less than 25hp on it, but 25 would be fine for 2 people, provided you fit a finely pitched prop. 2 stroke even better you could find one.

 

[Dino]

Most dory’s were designed and built in the 70’s and 80’s when outboards were much lighter 2 Stroke engines. The Dell Quay dory’s had very low freeboard so a heavy 4 stroke and a waterlogged hull could compromise your ability to keep waves from coming over the gunwale.
My recommendation would be to look at a 40hp 2 stroke or maybe a 4 stroke 30-40 if it’s a similar weight.
Loading of the boat will be critical also. Keep it light.

 

[dajoco]

Hi jfm, thanks for the quick reply.

I wouldn't put less than 25hp on it, but 25 would be fine for 2 people, provided you fit a finely pitched prop. 2 stroke even better you could find one.

Thanks jfm, I’m actually looking at 2 outboards at the moment. A 25hp 4 stroke and an old 30hp 2 stroke.

It will likely be a 2 stroke I will buy.
I would really love a 4 stroke for the quieter, less smelly and better fuel qualities, but I have no experience with them. The 2 stroke I can happily pull apart and rebuild when needing repairs. I wouldn’t know where to start on a 4 stroke as never had one.

 

[dajoco]

Most dory’s were designed and built in the 70’s and 80’s when outboards were much lighter 2 Stroke engines. The Dell Quay dory’s had very low freeboard so a heavy 4 stroke and a waterlogged hull could compromise your ability to keep waves from coming over the gunwale.
My recommendation would be to look at a 40hp 2 stroke or maybe a 4 stroke 30-40 if it’s a similar weight.
Loading of the boat will be critical also. Keep it light.

Hi Dino, appreciate the detailed response. You’re spot on with regards to the low freeboard. This is what got me thinking about putting a much lighter outboard on. The 60hp I put on I think weights about 110-120kg (old Mariner 675) Im just hoping that dropping to a 40hp that’s likely 40-50kg lighter makes a difference to how it sits in the water.

I think what I might do is put the boat in the water with the 60hp and mark the water level on the side and then repeat the process without the outboard and see how much difference it makes. I suppose this would be a good indication to how heavy the floor is and could prompt me to replace it sooner than later.

 

[Ferris]

Many moons ago I drove a 13ft dory as a sailing safety boat. It had a 30hp Yamaha 2-stroke and it did plane with 2 people in it very easily. I would say it did slightly over 20knots. Dory's plane very quickly, much faster than an equivalent RIB for example. I can remember seeing them plane fine with 15hp Yam's. Obviously this all goes out the window if its waterlogged. You'll never drain the water out of the foam by the way. See how you get on with a small reliable 2-stroke outboard and you can always upgrade the hull in the future. An inflatable (SIB) could be an answer, some of them are very good these days.

 

[dajoco]

Many moons ago I drove a 13ft dory as a sailing safety boat. It had a 30hp Yamaha 2-stroke and it did plane with 2 people in it very easily. I would say it did slightly over 20knots. Dory's plane very quickly, much faster than an equivalent RIB for example. I can remember seeing them plane fine with 15hp Yam's. Obviously this all goes out the window if its waterlogged. You'll never drain the water out of the foam by the way. See how you get on with a small reliable 2-stroke outboard and you can always upgrade the hull in the future. An inflatable (SIB) could be an answer, some of them are very good these days.

My uncle has a SIB which is great.

I understand that the floor, if wet will never fully dry out. Kind of like trying to get water out of a sponge without squeezing it lol.
Im happy to rip out the floor and foam and replace it. It’s not really all that big a job with the right tools, had just hoped to give it a good test run first to see how much I like the boat before committing to it.

Thanks for your reply

 

[stelican]

I had an Orkney Dory with 30hp Chrysler 2 t wife and 2 kids which we used to ski behind.
Then 28hp Yamaha on Olympic superdory did same both 4m boats