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Roy M · 02-05-2017, 15:48

This should be entertaining. You want a specific hull and style, designed to carry the compression loads of the mast on it's strongest element, the centerboard trunk, then you want to move the mast to a portion of the hull lacking that specific quality of strength, coincidentally, a tough place to get around, then past, to go forward into the forward cabin dressing room. Please keep us informed as to your progress. This will be most interesting.

owly · 02-05-2017, 16:21

Quote:

Originally Posted by Roy M

This should be entertaining. You want a specific hull and style, designed to carry the compression loads of the mast on it's strongest element, the centerboard trunk, then you want to move the mast to a portion of the hull lacking that specific quality of strength, coincidentally, a tough place to get around, then past, to go forward into the forward cabin dressing room. Please keep us informed as to your progress. This will be most interesting.

Your comment baffles me???? The mast will be located right against the main strength bulkhead that forms the primary structure of the boat. Please consider the fact that there is almost no down pressure on a free standing mast except the weight of the mast itself. There is no standing rigging trying to push the mast down through the hull. The heart of the Searunner structure is this H structure consisting of the two main strength bulkheads, one at the aft end of the dressing room, and one at the forward end of the galley, and the centerboard trunk. These structures support the down pressure of the stayed mast, the loads on the centerboard, and the beams that connect the amas to the boat. There is very little structural modification needed on the forward face of the forward bulkhead to carry the weight of the free standing mast, and there is abundant structure to carry the fore and aft and lateral loads imposed by the sail.
Yours is typical of the comments I hear on this. Poorly thought out, and not at all useful. Assuming you own or even have built a Searunner, both dubious assumptions based on this comment, it is obvious that you have little real world engineering background.

It will be interesting as you say, but not for the reasons you seem to imply.

H.W.

snort · 02-05-2017, 16:28

Yep, I'd find a design that already uses (or can use) a junk rig and stick with that. I don't see it on a Searunner.

owly · 02-05-2017, 17:05

Quote:

Originally Posted by snort

Yep, I'd find a design that already uses (or can use) a junk rig and stick with that. I don't see it on a Searunner.

Most folks don't see it on ANY trimaran. Virtually all junk rigs out there began live with a Bermuda Rig.

I regret even bothering to bring this up here. The same could be said of Roger Taylor's Corribee, or a Longbow, or Macwester 27, Blondie Hassler's Folkboat Jester, Pete Hills Benford Dory Badger, Bunny Smith's Dragon Fly Trimaran and on and on and on. Before it was done, nobody could imagine a junk rig on these boats.
It appears that I will not get anything useful here....... just folks who feel that it cannot or should not be done for very non-specific reasons.

I'm willing to hear and consider reasonable and thoughtful posts that can contribute usefully to the project or the rationally to the decision making process, but it's pretty clear that I'm way outside the "box" here. The junk rig has been proved workable on catamarans as a biplane rig, and Bunny Smith has shown it to be a solid workable rig on a Dragonfly trimaran. " I don't see it " is hardly a useful contribution. One would not ever step outside the box and experiment with something new if swayed by such comments. I have a strong aviation background, and the obvious parallels are abundant there. Burt Rutan with his "backward" aircraft, the EZ series being a prime example.

H.W.

snort · 02-05-2017, 17:16

You may get useful info on this forum, but, if I were you, I'd contact both John Marples and Jim Brown to hear what they think of the idea of using a junk rig.
Most Searunner owners probably have never considered the idea. It would almost certainly require a re-designing of the boat based on where to place the center of effort on your rig, which would be different than the sloop or cutter rig the boats were designed for.

Roy M · 02-05-2017, 17:38

I would be careful in my responses to this individual. Clearly, he has profound powers of perception. He certainly has me pegged. I think that I will go fishing until this blows over. Trolling can be most satisfying if you use the appropriate bait.

Cavalier MK2 · 02-05-2017, 17:40

Ah Owly is flying again. I'd suggest avoiding the a-frame and build the wing. There are a lot of rot spots because of the amount of times the aluminum arms and attachment points pierce the skin. The fabrication is more expensive. I did have one.
With any rig you have to make sure the center of effort is in the same place as the cutter rig. Or then you have to move the centerboard too.

So you have to brace the deck and add a step below to take the load. You could even go all out and have a junk schooner. Twice the fun and something in both cabins! Seriously I don't get it, if it is what you want to do, won't listen to anyone just do it. Put in the right place it will sail, if something breaks it needs to be stronger. Personally I think a Seaclipper 34 with the dory main hull would be more in the spirit of a junk plus a faster build. I hate the glass chines on a Searunner as they add so much weight. I'd make timber ones like the old Browns such as the Manta and bevel them if you have to have a 31. Check out the SeaClipper, John Marples might even help you!

smj · 02-05-2017, 17:53

Quote:

Originally Posted by owly

Your comment baffles me???? The mast will be located right against the main strength bulkhead that forms the primary structure of the boat. Please consider the fact that there is almost no down pressure on a free standing mast except the weight of the mast itself. There is no standing rigging trying to push the mast down through the hull. The heart of the Searunner structure is this H structure consisting of the two main strength bulkheads, one at the aft end of the dressing room, and one at the forward end of the galley, and the centerboard trunk. These structures support the down pressure of the stayed mast, the loads on the centerboard, and the beams that connect the amas to the boat. There is very little structural modification needed on the forward face of the forward bulkhead to carry the weight of the free standing mast, and there is abundant structure to carry the fore and aft and lateral loads imposed by the sail.
Yours is typical of the comments I hear on this. Poorly thought out, and not at all useful. Assuming you own or even have built a Searunner, both dubious assumptions based on this comment, it is obvious that you have little real world engineering background.

It will be interesting as you say, but not for the reasons you seem to imply.

H.W.

You should read Roy M's profile before you make a complete ass of yourself again. Roy built his Searunner 40' decades ago and still owns and lives on it. He also makes a living working on and improving boats.

w32honu · 02-05-2017, 18:09

I have been reading the latest here with interest...........Yikes!!!

I second the notion of consulting with John Marples and Jim Brown. If not for technical information then perhaps out of respect for the design and or the designer.

Such strong notions are often times a slippery slope.

Redreuben · 02-05-2017, 18:12

Owly; you have made your decision, identified the problems and say you have multiple solutions, and then predicted our opinions and responses.
So all that remains to be said is good luck with it, I look forward to seeing some photos of the rig and hearing wether it has met your expectations.

Redreuben · 02-05-2017, 18:16

Oh and for what it's worth, given your criteria, I would have gone balestron.
As far as junk rig goes I think the most promising endeavours for multihulls are the aerofoil types.
Cheers,
RR

Roy M · 02-05-2017, 18:40

Has anyone seen a junk rig on a hull that can perform at twenty knots? Fifteen? WILDERNESS has achieved these speeds with no special effort. Wouldn't a wiser inquiry attempt to match desired rig to most efficient hull factors? I mean, if you want higher speed, go one way. If you want higher payload and will accept lower velocity, the go another route.