Transom Cutout for Outboard...Problems?

Gillfowdy · #1 (**permalink**) 04-01-2008

Hello,
I have a 1976 Grampian 26 powered by a 15hp Honda 4 stroke outboard.
It's mounted to the transom at the factory location cutout.
My question is , does anyone have a problem with this design re following seas or any other problems? I know when I motor at hull speed, there is very little room between the water level and the cutout.

Phil

Faster · #2 (**permalink**) 04-01-2008

That's a pretty big, heavy engine for a 26 foot boat and when you're pushing hard the boat will "squat" quite a bit, lowering your apparent freeboard accordingly.

I don't think it (the cut-out) would be a problem in following seas unless you were motoring hard downwind at the same time... presumably if it's that rough you'd do better sailing anyway.

A lighter motor will help, but of course you're unlikely to want to go that route.

I'd experiment with the throttle settings, and see exactly how much speed you actually lose as you back the throttle off a bit, as opposed to how much you reduce the "squat" at the same time. There's usually not much point in over-driving a displacement hull for the little speed gain you may get. You really just make bigger waves and use more fuel...

Hartley18 · #3 (**permalink**) 04-01-2008

Ditto what Faster said. I'm not sure that 4-stroke outboards were in fashion in 1976, so you'll probably find it's a heavier motor than the designer had in mind. Make sure:

1. Your transom is strong enough to handle it. (Just check that you're not getting stress cracking..)

2. You get the trim right. (Try to offset the weight by moving heavy items forward in the boat..)

Bermuda30 · #4 (**permalink**) 04-02-2008

Never had any problems with it, though have not been in following seas larger than 3'ish yet. I have an older 8hp Yamaha, sit close to the water, but not dangerously so. The cutout should have slots for you to place a piece of 1/2" ply in the cutout, provided you pull the motor if it really bothers you. Only done this once, don't think it was really necessary. Do upgrade your scuppers though, the little 1" transom dumps aren't exactly the fastest flowing in a swamping situation.

Plumper · #5 (**permalink**) 04-02-2008

The problem is not from waves coming in the cockpit, it is if the waves wash right below into the boat. Given that the companionway opening on a G26 is so close to the level of the cockpit sole you should consider leaving the lower washboard in (and secured) when there is any chance of being pooped at all. There is nothing worse than a big gulp of saltwater down below!

sailingdog · #6 (**permalink**) 04-02-2008

This is why I built a proper bridgedeck for my boat.

Quote:

Originally Posted by Plumper

The problem is not from waves coming in the cockpit, it is if the waves wash right below into the boat. Given that the companionway opening on a G26 is so close to the level of the cockpit sole you should consider leaving the lower washboard in (and secured) when there is any chance of being pooped at all. There is nothing worse than a big gulp of saltwater down below!

Bermuda30 · #7 (**permalink**) 04-02-2008

Quote:

Originally Posted by Plumper

The problem is not from waves coming in the cockpit, it is if the waves wash right below into the boat. Given that the companionway opening on a G26 is so close to the level of the cockpit sole you should consider leaving the lower washboard in (and secured) when there is any chance of being pooped at all. There is nothing worse than a big gulp of saltwater down below!

Indeed. The Gramp companionway bottom is about 6" off the cockpit sole stock. I myself intend to build a full bridgedeck to cockpit seat height at a later date, before venturing further offshore. There's a lot of volume in that cockpit, and a bridgedeck is a good way to solve the companionway height issue and reduce the volume for waves to swamp.

sailingdog · #8 (**permalink**) 04-02-2008

Bermuda30-

If you want to see the install I did on my boat, let me know... I'll pm you a link.

Plumper · #9 (**permalink**) 04-02-2008

Quote:

Originally Posted by Bermuda30

Indeed. The Gramp companionway bottom is about 6" off the cockpit sole stock. I myself intend to build a full bridgedeck to cockpit seat height at a later date, before venturing further offshore. There's a lot of volume in that cockpit, and a bridgedeck is a good way to solve the companionway height issue and reduce the volume for waves to swamp.

My Ranger 26 was a similar boat to the Grampian and it had a motorwell like a power boat. It basically consisted of a bulkhead in the after part of the cockpit ahead of the engine mount cutout so that an overtaking wave would just fill the motorwell. If you see a Ranger 26 check it out. That is another solution to the problem.

Gillfowdy · #10 (**permalink**) 04-02-2008

Thanks for the quick reply. I do plan to keep the 15 even though it's heavy. 103lbs!!! It runs great and is what I got with the boat. Keeping some items forward in the boat seems like a good idea for weight balance. I do have a piece of ply to fill the cutout but only use it during storage of the boat. I don't know where I'd put that huge thing if I removed it during a sail!
The scuppers are small but I've never even had any water in the cockpit yet

I sail Lake Huron and intend to head north to the North Channel this summer so could run into some not so nice weather. May need larger ones I guess. I would like to see the bridge deck mod if you could forward the pics to thebus@sympatico.ca

Thanks
Phil
76 Grampian 26
Irish Mist