Subject: Re: [harryproa] Wing mast on stub?
From: Rob Denney
Date: 11/24/2009, 2:16 AM
To: harryproa@yahoogroups.com.au
Reply-to:
harryproa@yahoogroups.com.au

 

The bottom bearing is accessible with the mast out on a one piece mast.  The top bearing on a stub mast is not accessible, unless it can be removed from the mast.  I would do this for peace of mind. 

You can't "just" epoxy the top back on, but with a bit of uni each side it would be feasible.  An internal sleeve would be prettier, but 10m up in the air, no one will notice.  I would go with the mast length you want, then when you decide to ship it, cut the mast and make a sleeve, either internal or external.  I would also consider a wing mast rather than a tube.

rob

On Mon, Nov 23, 2009 at 10:44 AM, Gardner Pomper <gardner@networknow.org> wrote:
 

It would seem that you would have a hard time getting to the bottom bearing, when it is down in the lw hull if you don't have a stub mast. Do you make removable bearings there too?


I also wonder if I am being too concerned with fitting the mast in a container. Would it be reasonable to just chop off the top 8' (or so) of the mast when shipping, and then just epoxy it back together at the destination? The very top portion of the mast should not have all that much stress on it (other than the halyard tension).

Another idea is to build the boat with taller masts, and if I ever decide to ship it, just have shorter ones made. I imagine that pretty much anywhere I go will have more wind than the Chesapeake Bay. I might even be able to use the same sails, just always reered down one reef. I assume this is a pretty expensive solution, especially if I am looking at a schooner rig.

I guess all of this could be solved by a 2 part mast. I figure I can get the same sail area from a ballestrom rig with a 55' luff than I can from a schooner rig, with 2  33' luffs.

- Gardner

On Sat, Nov 21, 2009 at 9:53 PM, Rob Denney <harryproa@gmail.com> wrote:
 

I don't like stub masts (heavy, can't get to the top bearing), but where height is limited, they may be worth the effort.   Easy enough to make, as long as the bearing assembly for both bearings is installed in the mast prior to joining it together.  Not a big deal.  Could make the assembly removable pretty easily too, which solves some of  the maintenance issue.

His bearings are spherical, mine are plain. We have had no trouble with these so far.  Suspect you could get a spherical one made for a lot less than 5 grand. 

Half a wishbone is ok if you can stop it twisting, or live with it interfering with the lee side of the sail on one tack.  Not a big deal. 

rob





On Sun, Nov 22, 2009 at 7:32 AM, Gardner Pomper <gardner@networknow.org> wrote:
 

Hi,

I was just http://www.sponbergyachtdesign.com/ looking at his wing


masts. The idea of a stub mast with the wing mast rotating on it
appeals to me for my containerizable boat, so that I can get more sail
area. Will this work with your mast build methods and bearings? I like
the sound of your $350 bearings alot more than his $5000 bearings.

Also, what about his idea of a half-wishboom boom? If I angle the boom
up like that, I could have the clew above the hardtop over the ww
hull, and still have the sail low enough to work on at the lw hull.

Still thinking...

- Gardner
York, PA



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