On Wed, Jan 22, 2014 at 1:20 AM, <bjarthur123@yahoo.com> wrote:
rob-- many of your designs, i'm thinking of expeditionary in particular, use gin poles to demount the masts on the beach for trailering. is it possible to take the masts down while on the water if the weather is nasty? for less windage / lower center of mass. farrier's for sure can, though i doubt anyone has done it in anything but calm conditions.
If the gin pole is rigid enough and the hoist is quick enough, it would be possible. We are currently building unstayed masts for 12m cats which have a hinge just above the boom. This would be another option. Both would be easier than a Farrier type drop with similar size masts. Unstayed masts have lower cog and less windage than many stayed ones, so it is less of a problem.
Luc As a thought experiment in the extreme I imagine the ww hull to be a free fall lifeboat, the rig to be limited in size as to not cause a capsize when kept sheeted, up to, what, 60 knots of wind, and explosive bolts that automatically demast beyond that. There goes fast, simple and light.
A 15m x 8m raft, with raised rudders so it draws 150 mms or so is going to take a lot to capsize it. Add a parachute anchor and it would be even more so. Blowing off the mast would not be necessary and leaves you looking a bit underpowered after the storm has passed.
I have not found much about the difference between flat vs round bottom in this respect – I suspect that the sharpness of the outside corner of the chine could be the determinant factor.
One of many. Clean bottom, fairness, no holes, no turbulence inducing lumps, weight are more important than the hull cross section, especially in a long, skinny, light hull.
On the subject of shallow draft, we took Rare Bird for a sail the other day. Coming back at low tide and approaching some mud flats, we decided to anchor so lifted the rudders and dropped the hook in the very murky water. The shank of the anchor was clear of the water surface!
rob
ben
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