I had a couple questions. Were you going for engineless, or are you planning on mounting an outboard somewhere?
Also, it looks like you can't retract the rudders and still steer, so I was wondering what the draft is.
Just for curiosity, what is the masthead height above the water?
On Sat, May 31, 2008 at 8:32 AM, Raps callion <firstname.lastname@example.org
I love the trailerable design. It exceeds my expectations in almost every respect.
The part I love the most is the building cost and the bruce number.
I would love to see another design with 6' headroom, trailerable, a bruce number
this high, and at this price.
----- Original Message ----
From: Mike Crawford <email@example.com
Sent: Friday, May 30, 2008 8:56:53 PM
Subject: [harryproa] Re: Trailer proa
The trailerable proa looks wonderful. I was skeptical at first, but
now that you've upgraded the renderings, I can see that the boat really
does have some character of its own.
That's also a great mast stepping solution. Some tri's require a
trailer to step/unstep, and that's not very useful if you're moored or
at a dock. Others have a-frames or gin poles, which help, but which
also create some serious stresses on the mast base. They are also more
suited for a rotating mast that fits onto a ball than for an unstayed
rig that needs to be lowered several feet into a hull. This is
probably the simplest and most stress-free solution I've seen.
The number of trailerable boats with this level of performance and
accommodations can be counted on one hand, with a few fingers to spare.
Rob Denney wrote:
Trailer proa renderings are in the Files section under Maxi Trailer
'The ultimate trailer sailor/racer cruiser' is the requirement for
this boat. As fast as possible, with standing headroom, minimal
galley, double bunk and a toilet. Trailering is mostly for the 5
mile trip from home to ramp, but occasionally further afield.
Windward hull is 7m.24', leeward hull 12m/40'
The boat is 6m/20' wide in sailing trim, but telescopes to 3.7/12'4"
wide for marinas and 2m/6'8" wide on the trailer. This is easily done
with composite beams. The mast and boom travel in cradles on the lw
hull deck, the beams under the cockpit. The trampoline is in two
pieces split fore and aft. Each piece has a 25mm dia carbon or alloy
tube sitting in hooks on the hull and the beams. In the middle is a
thicker tube for each piece. When telescoping for marina use, the
lee hull tramp is lifted out of it's hooks and as the hulls slide
together it slides over the windward tramp, so you can still walk
across to the other hull. For light air races, it can also be sailed
like this. For trailering, the tramps and the telescoped beams are
quickly and easily removed and stored under the the cockpit.
The mast is telescoped to 9.2m for stepping/unstepping . A 5m long
pole, with a 4;1 blocjk and tackle on one end is inserted into a hole
in the deck next to the mast. The heel sits in a cup next to the mast
step. The blocks are tied around the mast at it's centre of gravity
approx 3.7m from the base and it is lifted up until the heel is above
the deck, then guided into the top bearing and lowered into place.
Unstepping is the opposite. Very quick and very safe.
The reefing drawing shows sail areas incl mast of of 47 sqm/505 sq',
35 sqm/376 sq' and 22 sq m/236 sq m. Storm sail is 2 sq m/22.5 sq' of
mast. Lots of sail up high for the light stuff, no drag or weight up
high for the heavy.
Weight in sailing trim is 420 kgs and the payload 330 kgs/726 lbs.
Overload could be as much again without it affecting anything but the
Construction method for the hulls is partially glassed panels joined
and compounded, with flat panels for the rest.
Bruce number empty is 2.34. With normal payload, 1.9. Hull flying
wind speed 10 knots, lower with the crew sitting to leeward.
Inside the ww hull is a double bunk at one end and the galley and
toilet at the other. The galley space is large, but not all of it is
accessible. It will probably end up being accessed through a deck
hatch and used for storing fenders, etc.
The cockpit is sheltered with a folding pram hood which will ensure dry
The rudders could not be mounted on the telescoping beams, so are in
daggercases in the hull. Rather than use long tiller extensions,
there is a short athwartships tiller (magenta in the renderings) with
an extension (green) attached to the tiller and a car on a track on
the deck. The car is pulled fore and aft by lines running to
whipstaffs (vertical tillers, red) on the leeward end of the cockpits.
The lines are cleated on the whipstaffs so can be released and easily
replaced and retightened when the rudders are lifted and lowered.
This is a far easier system than wheel steering where the lines must
be released off the quadrants to raise the rudders.
Comments, suggestions, criticisms welcome.