Wants to broach

Hi all,
I have an 8m jackman that likes to lean over towards the on coming sea when traveling side on, it rides great directly into and with the sea.
I feels like the rail grabs and pushes the nose down make you have to steer out of it the it will jump to the other side ( can be quite scary at times).
I think the person that built it has put more cabin on to the it was designed for.
I have 300kg of ballast in the transum that helps a lot.
I’m looking at getting 2 large chimes weld on either side to try and help push the nose out.
Thoughts if this will work or other ideas please

 

Sell it for a loss and move on.

 

Nice looking boat all except that it appears hopelessly top heavy and hints that it would run down by the bow.

The skippers chair is way above the center of buoyancy and that alone is enough to influence the behavior of a relatively small boat. Aft end of the top appears to have vertical rod holders. Even the rods would have a small but measurable affect.

300 kg is a lot of ballast for such a boat. Take an inventory of all the things that you can remove from the forward end of the boat. Twould be a shame to have to remedy the situation by using Light Fandangos advice. He may be closer to the reality of the situation than is pleasing to contemplate.

 

It is a lovely looking boat , even with the advise of it's issue it may sell for not much less, with a guilt free conscience, fine in a river or some lakes,. fair weather..no swell..? Not many in WA

 

Fully concur.

All skippers chairs are.....one assumes you mean the CoG.!!

 

Talk of a fire-sale is premature, the boat needs thorough experimentation with trim tabs, properly used, cross-wind lean is common in such boats with high forward structure, and with a single engine, tabs/interceptors are your only way to correct it. 300kg of ballast ? Are you speaking of the engine ?

 

Are there any examples of this boat that run well. For example, with a sterndrive installation?

 

I take it the transom ballast is the engine?
My first response was to sell and move on.

 

Can this form of spray strip be the cause of this particular behavior?

JS

 

Not likely, perhaps the opposite.

 

BleuBell
Do you have any concrete experience? Otherwise, your post has extremely limited value.
JS

 

I do, but "buyer beware".

 

So the boat "leans over" when traversing beam seas, and the lean is toward the oncoming waves. Then, reading between the lines, it jinks around as waves pass under the boat. That is not "broaching", especially since he says it runs perfectly well, down sea. It sounds like the lean is induced by the helm being put over, in the cross wind that is producing those waves, to keep the high bow from being pushed down-wind. I'd advise using tabs to correct the lean, and trimming the engine in, to move the CLR more forward, so your line of thrust isn't pointing so much off-centre, which will steer the boat as the CLR oscillates back and forth.

 

The chines are angled down rather severely, sounds like the boat may be tripping over them when a wave pushes from the side.
I don’t think additional chine outside the hull is the best approach to that problem.
I think the existing chines are turned down so far that they are acting as skegs, tripping the boat as the wave moves under it.
How about filling the chine until it becomes more of a chine flat than a skeg?

 

I'm guessing the inertia of that relatively tall superstructure causes the problem. When the boat meets a wave the hull is slightly slowed down and veered away while the superstructure will want to continue forward in the previous direction. That would make the boat heel into the wave. At least it could contribute to such movement. Counterbalance weight would, as you noticed, help. If I'm right, reducing the superstructure weight/height would help even more. my2c.