Subject: Re: [harryproa] Re:: Bucket List harry forum
From: "Rob Denney harryproa@gmail.com [harryproa]" <harryproa@yahoogroups.com.au>
Date: 10/19/2014, 10:04 PM
To: harryproa@yahoogroups.com.au
Reply-to:
harryproa@yahoogroups.com.au

 

Welcome to the chat group.  Answers follow your questions.

Now I find the new Bucket List really fascinating.  To that I have a couple of questions

- From the pictures it seems to me that the mast is round and there is a sail track and battens, so the mast will have to rotate.  Is this so, and have you considered a more airfoil or teardrop shape mast?  I suppose a wing mast would add complexity as its rotation would have to be controlled relative to the sail?

The mast does have to rotate, but not relative to the sail.  A wing section would improve performance, but at the cost of complexity.  There are also issues with wing masts in gales and when maneuvering under motor.    For the charter boat, a round mast.  For a personal boat, whichever one appeals most. 

- With this rig and sail, how do you control sail twist, to compensate for different apparent wind angle at the upper part of the sail ?  I suppose this will be important on such a fast boat, and could also help to spill wind high up when needed.

The mast flexes in strong breeze and the top twists, depowering it.  The amount of twist is controlled by the outhaul, which runs from the end of the boom to the base of the mast.  The tighter it is, the less the sail twists and the more the mast bends.  With such a tall mast, there is always going to be excess twist with this system.  So, upwind in a breeze, some of the sail will not be doing much.  If we get the dynamics right in light air and off the wind, all the sail is working.


-would it be feasible to have both a racing ww hull (as standard), and a cruising one (Solitarry type), and to just pick the one you need when assembling, before launch?


No problem at all.  However, the beams and maybe the mast would need to be sized for the extra weight that will be in the cruising hull.  


- Would a folding option be possible on the Bucket List?  Or would it be too complicated and heavy?

No problem.  Would definitely add weight and cost, but not a huge amount. 

I like the simplicity and inherent stability of the Bucket List, but the width of the assembled boat does raise some issues.  My nearest boat ramp is too narrow, and so are most other boat ramps around here. 

- How about trailering it with a medium sized car?  The weight seems not to be a problem, but I have not seen any flat-bed trailers of 12m length around here, so I guess it would have to be a specially made trailer.  Also, driving around with a 12m long trailer may be challenging, especially on narrow roads like ours.

The length is the tricky bit.  Could make removable ends to bring it down to 11m, but even that is a difficult tow. 


-Is it possible to take down and raise the mast on the water if using a gin-pole or a large tripod-like structure to provide a craning point high up?
I am thinking about low bridges, which also may be an issue for me.


No problem. 


I think the Bucket List -project is a great initiative and I hope it will be a boost for the acceptance of proas around the world.  I wish you good luck with it going forward.


thanks.
regards,

rob 


Regards
Rune


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Posted by: Rob Denney <harryproa@gmail.com>
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