Samwise - Part 2

Comments

• I am sure, she will definately NOT self steer.
  As the center of lateral-surface is much foreward of the center of thesail-area.
  The ama will produce additional drag, and so it will turn even more to windward.

  Jorn, Valencia

  Posted by  on  02/06  at  10:11 PM

• Yes, except the leeboard pivots aft. I’m building a model, so we’ll find out then.

  Posted by Editor  on  02/07  at  01:18 PM

• I’m pleased to see this design is progressing. I would agree that the balance issue definitely needs sorting out. That windward hull is going to produce a significant amount of drag. Self steering is a nice idea, and with open water steering with sails alone should be viable. The fact remains though that unless you get that lateral resistance a fair way aft none of this can work.

  Making the sides 2’ high is sensible, minimises waste. Any thoughts on materials yet? With two fairly long and weighty hulls those beam attachments will see some significant loadings. This is certainly not pacific proa.Have you come up with any details here?

  Leon.

  Posted by  on  02/08  at  02:23 AM

• Michael,

  Its just a simple calculation of surface centres.
  For your design, you have to move the lateral centre about 3 meters! to obtain balance.
  Can you imagine how long the swinging daggerboard needs to be?
  I have done thi calculation several times for my 33 ft design, and i always ended up with 2 independend daggerboards, which will do the job.
  Additional steering-gear is required as well.

  Whts with Rozinante?
  Sche certainly had the same problem.
  Why are not more pictures of Rozinante on your Site?

  Best regards

  Jorn, Valencia

  Posted by  on  02/18  at  10:01 AM

• Thanks for the comments and advice, much appreciated. The C of A is 3’ aft of center, as should be the board for balance. Since the pivoting leeboard would need to be at least 7’ long to achieve such a shift, I see your misgivings.

  I have a few more options on the drawing board - the favorite at the moment being a pivoting bow-tie shaped centerboard, which does the job - at the cost of a centerboard trunk.

  Rozinante had plenty of problems, but extreme weather helm wasn’t one of them.

  Posted by Editor  on  02/19  at  04:52 PM

• Michael,
  I like this design a lot.  We live in the same area (I’m in Port Angeles) and have the same design brief and have come up with similar solutions.  Mine never got past the model phase, three and a half years ago, but I still want to build it.  It is here http://groups.yahoo.com/group/proa_file2/files/Proazoa/
  There isn’t much I would change.  I appreciate your reasons for putting the rig on the lee hull, but I decided on the ww hull to make it easier to access and simplify constuction of the partners.  Also my ww hull is 24’ as is the ama.  I probably would now go for some sort of lug too, after using it on my Dovekie knockoff the last few years (Duckworks: Bufflehead) I envision the cockpit more open than yours, basically just dodgers with a canvas top to pull over.  Minor differences.  It would be exciting if we both built these boats.  I’m leaning more and more towards it lately.  After ruminating on proas for 30 years it is about time I built one.  My first step would be to develop the Stoaproa more, as I’ve only sailed it as a tacking outrigger so far. That might help work out some problems on a smaller, cheaper, scale.  I have no definitive rudder solution, but some ideas to try.
  Good luck with it if you decide to go ahead. 
  Gary

  Posted by Gary Lepak  on  03/07  at  09:45 AM

• Hi Michael

  I’ve got my boat schooner rigged now, and must agree with the doubts that your design as drawn will self steer.  I have a small leeboard, to be replaced here on the next trip with a big leeboard, but I still need rather a lot of rudder on a reach, and still have to luff the aft sail at times to ease the helm.  Remember that the CLR of the hull alone will be at about 25% aft of the bow.  The leeboard will take some of that load, but not all of it.  You’ll be averaging the CLR of the hull with the CLR of the leeboard, the result of which will be well forward of the centerline.

  I dropped my digital camera in the lake :( so no new pics right now, but I just bought a new one on ebay.  I’ll post some pics on my wikiproa page when it comes in of my two solutions to the aft CE problem in a schooner; one is a working, pretty simple rudder system, the other is <gasp> a jib.  Nice thing, a jib, if you can manage it during shunts.  My hope is to fly the jib on long reaching legs, and to sail windward legs with a cat schooner rig, to make the shunts faster.

  Schooner rig very good, very safe feeling, easy to shunt.  Keep at it, good concept.

  best

  Kevin

  Posted by Kevin  on  03/07  at  10:00 AM

• Hi guys, thanks for the comments. VERY appreciated.

  Gary - thanks for reminding me about Proazoa. Oddly enough my latest sketches feature equal length hulls and dodgers fore and aft, rather than a fully enclosed cabin. I may even get around to mounting the rig in the windward hull! Basically re-inventing Cheers all over again. Maybe that Newick fellow knows a thing or two after all.

  Kev - a jib… who woulda thunk? Thanks for the info about your schooner proa. I read the wikiproa entry - very interesting.

  Posted by Editor  on  03/07  at  06:35 PM

• Like the idea of forgoing the rudder.
  A small yolk ad each end to hold a steering oar might be usefull.

  Have you considered chine runners a-la Matt Layden rather than a centerboard?

  Posted by  on  03/11  at  04:15 PM

• Hi Brian, yes, chine runners are a possibility. An asymmetric lee hull (like a Hobie) might also help. The steering oar back up is a wise move.

  Posted by  on  03/13  at  09:28 PM