Gardner,
Good points.
SPEED.
I didn't meant to imply that you want bugs in your teeth in really
shallow water. You just got lumped in with the low-draft
requirement because that's high on your list.
Light wind performance is actually more important that max speed
to me as well. While I do need to hit 20 knots before I stop
counting (I've been to 17.5 so far, so maybe this summer...), I'm
starting to prefer 8 knots to 12 or 15. At some point in the double
digits, the apparent wind turns into a roar and things in the water
start approaching too quickly, and things aren't as relaxing as they
were at 10 or below. I want the *option* to fly across the water,
but the ability to move nicely at low wind is more of a draw.
Which is why I want the proa with an unstayed mast: you can have
an otherwise dangerous amount of sail area up (for a singlehander),
and go from full-on to full-off isntantly, as needed. Because gusts
and squalls do happen.
TILLER.
The tiller would work like it does on Rob's woodenboat challenger
and 10m camper in the Files section of the group -- a long
trimaran-type extension on a standard tiller at the top of the
rudder.
The extension can be modified in length by a few feet with a
twist, providing some flexibility in the cockpit. Some of these
extensions have a ball-shaped end that will drop into a
keyhole-shaped receiver in the cockpit, so you can pick a length
(neutral steering) and then lock it. See the Forespar tiller
extension lockbox:
http://www.forespar.com/products/tiller-extension-lock-box.shtml
I'm sure you could rig up a similar system for an extension with a
hand grip as well.
So if you shunt, just drop the aft tiller into the lock, switch
sides, and grab the new aft tiller.
AUTOPILOT.
As for an autopilot, I'd use a Raymarine ST-4000 tiller pilot.
The control goes inside, or at least at the cockpit, and just the
mechanical portion sits out, the base connected to the leeward hull,
the end connected to the tiller (not the extension). I use one of
these on my catamaran with great success. If patched into the nmea
system, you can even have it steer to GPS waypoints, or to the
average wind direction of the last minute.
Plus, I just love using the Raymarine wireless smartcontroller
remote, hanging out on the bow tramps and steering with a button.
It's not necessarily a wise way to sail, but when motoring back to
the mooring against the tide, it's great fun.
12' FOLDED BEAM.
I hear you about not being able to fit in a full-sized permanent
cockpit in to a 12' width while folded. I've tried, and if
everything is just so, it might be possible, but only if I skimp on
the interior, the cockpit, or both. Given that I'm shooting for a
table inside, and a 6' cockpit, there may be no way it can happen
unless there's a funky system like your Contrarry where the cockpit
overhangs the leeward hull when folded.
Going along with your idea of a removable cockpit (or Dennis'
flip/folding one), how about a 14' width to 16' width while folded,
going down to a 10' or even 8' width while trailering?
I think a 14' to 15' berth width is pretty standard for a 48'
sailboat, so the boat should still fit into a marina with the
cockpit intact, without messing with the cockpit, and still allow a
narrower trailering width than my 12' goal. That would be a neat
combination. While I wouldn't mind disassembling the cockpit for
the rare trailering session, I wouldn't want to have to mess with it
every time I leave or tie up to a berth.
This would be the best of both worlds.
FOILS.
Could you point me to an image of Todd's design with a fixed
vertical steering board? I think you mean the one here:
http://www.youtube.com/watch?v=Jn8fr0PaUqg , but want to check
If you went with this, how would you incorporate raising and
lowering the foils? Or would you just count on your hull design to
counter leeway, and have the foils raked way back for sailing in
skinny water? And how would that work with the hull profile you're
planning on?
I can see Todd's hulls being *great* at preventing leeway, but I'm
not so sure how well they'd work on a 40+ footer at a very low
draft. But then I haven't tested them, nor tried to calculate the
draft at full displacement. If it works, there's a lot to be said
about effective leeway prevention that doesn't depend upon any
foils.
- Mike
Mike,
Just a couple of comments:
BD has special draft requirements, as does Gardiner's plan to sail in the Chesepeake, and both could be nonoptimal with low-draft beam-mounted rudders. Without enough foil in the water, it's easy to go from laminar to non-laminar flow, and then the foils become a lot less effective. But such is the challenge with a 48' boat designed to sail in 3' water, and yet somehow be expected to hit 20 knots (by observers, not by the owner).
I don't want to sail at max speed (15 knots will do for me!) in 3' of water! I just want to be able to sail at 5-6 kts in shallow water. I want to sail at 15+ kts in deep water (> 30'). I even want to ghost along at a couple knots in 1-2' of water (with a soft bottom, like mud or sand) for anchoring. It is very important to me that the rudders raise, but it is also important that they lower to 5' or so.Just as important, rudders on the beam would permit simple tiller extensions all the way to the cockpit, which is something I'd definitely like to try. It's a simple system that wouldn't care one way or the other if the boat were folded or unfolded, won't stretch out of shape, and will be more fun than using a wheel. At least for me -- I much prefer tillers.
I am not clear on the tiller idea. I would be happy enough with a single tiller, but I am having a hard time seeing the use to two tillers; sometimes one at a time (having to stow the other partway through the shunt) and sometimes both (to be able to use both rudders). Am I just missing some simple way to do this? Plus, I am not willing to give up on autopilots when cursing, so how will that work?
Because of these questions, I am trying to move forward with the idea of using a wheel. As much as I love how clean Rob's new rudder desgn is, I don't see how to make the steering simple. Instead, I think that Todd got it right with his rudder design, where the steering board is fixed vertically, and the rudder case is pinned to that board and kicks up independently. That allows the steering system to work regardless of the cant of the rudder, or to impact.
Btw, I have also hired Rob to try to help put a design to paper with all my weird-ass requirements (on water folding, fit in a shipping container, etc). I think I may have had to give up on the 12' beam for trailerability (sorry, I tried to put that one in just for you!) but for now, there would be (minor) disassembly to make that happen (have to remove the removable cockpit). When Rob has beaten some sense into me and come up with drawings, I would also be happy to share with the group (with Rob's permission).- Mike