Rethinking Hobbyhorsing/Pitching

[BigCat]

It doesn't lookdown in the stern, but somebody could have just repainted the bottom to reflect the new trim of the boat after all the work was done.

[ssullivan]

Thanks, BigCat. I will have to take a good look at the survey pics to see if there is any type of slant to the bottom paint.

[Tropic Cat]

I dunno, she may be 6 inches to a foot high in the bow. I think you can see it better here.



You know Sean, I completely forgot about all that gorgeous stainless steel in the bimini and davits that you have over and behind your cockpit. That wasn't in the original design spec. I wonder what that weighs?

Hmmm..maybe we're approaching this all wrong. Maybe you need extended sterns to compensate for all the extra weight in the stern?

[ssullivan]

That's a good picture, Rick.

Of course, the engines are pegged (well, 2500rpm) in this photo so some of what you see is "stern squat" from that. It doesn't sit like this when at rest.

The arch in the back is 100% aluminum tubing.

Yeah, maybe I need to make it an 11M, via stern extension?

Anyway, this picture helps visualize the weight distribution. That entire huge list of things I mention as being in the "cockpit area" are from where I'm standing and back. Judging by their weight, looking at the length of the boat and where they all sit in it, I can see the angle of pivot being just forward of where I'm standing - which is where I percieve it to be when it shoots skyward.

Originally Posted by rickm505

I dunno, she may be 6 inches to a foot high in the bow. I think you can see it better here.



You know Sean, I completely forgot about all that gorgeous stainless steel in the bimini and davits that you have over and behind your cockpit. That wasn't in the original design spec. I wonder what that weighs?

Hmmm..maybe we're approaching this all wrong. Maybe you need extended sterns to compensate for all the extra weight in the stern?

[BigCat]

Here's a tip-to make their lives easier, boatbuilders usually level a boat so that they can use levels and plumb bobs when building a boat. So, check your cabin sole and major bulkheads for plumb and level. If they seem to agree, and, for example, are 5 degrees off plumb fpr bulkheads and off level for the cabin sole, you have a pretty good idea of where you stand.

[Tropic Cat]

I've been adding this stuff up:

So, We have
6 T-105's on the transom -- 600 pounds
Heavier engines 200 pounds
Dinghy and engine 200 pounds
Davits and bimini 200 pounds ?? (probably heavier)

That's 1200 pounds of stuff mounted behind the engines!!

[beau]

Sean,
Hobbyhorsing is part of owning a multihull, just like healing is too a monohull.
It is a different motion, but you do get used to it (somewhat)
I found with my design that by widening the stern, the hobbyhorsing is significiantly reduced.
Also as suggested, quartering into the waves or adjustment of speed helps. Under sail hobbyhorsing is less that motor alone.
Regards,
Beau

[Whimsical]

Originally Posted by ssullivan

PS: I can do one better than $10 for concrete. How about $0 for some rocks found on the shore??

Even better idea. Get a load of white pointers on the fordeck. If you do post pictures.

Mike

[ssullivan]

Originally Posted by Whimsical

Even better idea. Get a load of white pointers on the fordeck. If you do post pictures.

Mike

Damn... where is that Oz to States translator when I need it. I KNOW this is probably a hillarious post. Many of yours are.

If only I knew what pointers were in this case...

[beau]

there are a couple of aussie translations.

One is topless ladies sunbaking on the beach (really pink pointers) or red pointers if they have been there too long.
I would post some photo's but this forum is very "politically correct" the moderators didn't like my last post of "how NOT to use a hammock"

The other is a very large Shark that inhabits the waters in southern Australia and south Africa

[bill good]

Those photos will get him more interest!!

You have not told what happens with the sails out. Put out the head sail at least. It will stop the bows climbing up & dropping off by holding the bow down. Motor sailing will bring up you speed. (and if you get more RPM it will indicate if the props need more looking at)


Bill

[terhohalme]

So, did you start to design the stern extensions?

[Eleven]

I hope you realised that bags of sand are more freindly than rocks, specially when she starts dancing in heavier weather.
It'll only prove the cg's too far back (or not). The side on view of the keel tells some of the story rocking chair shaped. And vee hulls dont splash enough to absorb energy. The Prouts used semi-cicular hull bottoms to provide dynamic damping. And a straighter line in side view.
Small strakes, three inches wide, a couple of feet long onthe rear of the hulls and below water line will add a bit of drag and a lot of damping. Needs a strong mounting.
Apart from that you've got a roomy boat that nods a bit, the old prouts were shallow in the main cabin and rode a bit better. Trimming the cg is the long term answer. Good luck with it.

[BigCat]

"And vee hulls dont (sic) splash enough to absorb energy." Too broad a generalization- It depends on the degree of flam or flare, and the amount of overhang, if any, more than the shape.