Sea Sled madness. It’s in my brain.

Thanks Tom. It was a thrill having a real pilot show me what she can actually do.

I will just add that the numbers @BlueBell provides are while pushing a 9 ton brick shape against wind wave and tide.

 

What do you mean by lotsa heel Tom?

 

She rolls to the inside
on a turn, exactly as you would want. Heel girl!

 

Oh, I see, not as a catamaran.

 

An edit to my earlier review:

A few things to add here I overlooked earlier in my review, ( Post #3450 ):
The helm trim/tilt control was unserviceable.
John had trimmed down ( at the engine ) while pushing the dock to get the prop deeper. Prudent.
He left it there ( on purpose ) once we disconnected and went joy riding.
So, with that said, I will add the following observations:
There was no porpoising, zero, not even a hint, despite a positive pitch angle.
There was no "sneezing", zero, nothing.
I recall these being sizable concerns earlier in the thread.

 

The lowest tide in a good long while. Serenity is stuck at her slip for another few hours.
On the plus side, it isn't raining. That's nice.

 

A new towing hardpoint. Just forward of the steering axis of the ob. Because sometimes what we are moving isn't suitable for pushing.

 

Is that thing on top of the house supposed to be a pulling point, I mean, really?? If yes, then rethink!!! (Start by checking how many diagonal support members you have between deck level and roof sides...... and then check how much shearing force your windows and pillars can take).

 

Usually, the tow cleats are on the hull and then you’d make a bridle to get behind the engine. This does put the tow line in the sea, but I’d not hook to the roof. To be 100% honest, I did not even see it until bodo mentioned it because I’d never cleat there.

If you wanted a higher tow line; then bridle off the two cleats you already have….or add a cleat to the starboard side same like the port and bridle, that is..

You may be careful enough for the high cleat, but the one time your buddy borrows the boat and tries to pull Mt Ranier off the oysters with a running start; the entire roof and windows might cant.

 

The intent is to tow small stuff, like a boat or a dock at 2 knots. The roof can take around a half ton of pull. All the windows are lexan, and fully integrated into the structure.

If anyone borrowed the boat and tried to pull something, they'd choke to death on their own blood and smashed teeth.

I had towed from a bridle a couple times. Massive pain in my transom. Load transfering from one hull side to the other makes control miserable.

I should have been clearer in my post. Big heavy loads get pushed. Light easy stuff can get pulled.

 

Even so, it would be prudent for you to install some diagonal bracing to resist the loads on the top of the aft bulkhead.
Not much you can do though, other than installing timber compression posts going down to the transom?

 

What is the maximum bollard pull I can reasonably expect with a 16×17 prop at rpm <1000 ? I can apply that as a load, with a bit of fuss. 41x43cm

Towing a ruined dock last year, I broke a ¼ , 6mm poly line, with a touch of the throttle.

 

I am condident in the roof, longitudinally, since I had considered those loads while building, but I just realized that a strong side pull will tend to tend to pull the roof sideways, since it is, structurally, an open ended box.