Subject: [harryproa] Re: Charter proa deckplan question
From: "Robert" <>
Date: 5/27/2008, 5:13 AM

--- In, "Rob Denney" <harryproa@...> wrote:
> G'day,
> All sounds possible, especially the hull/bridgedeck panel with the
> Comments:
> Make the telescoped beams easily removable and it will trail at 2m.

Can easily see 3m, and can just see 2.5m but it took me a while to
work out 2m. 2.5m is less effort

> The lee hull bury only needs to be 10%, both for the mast and the beams.

I would have thought 18% would reduce the vertical compression, but I
suppose this is only a small area of reinforcement needed. I thought
it would also make it easier to resist the racking loads and allow a
bit more to play with in hatch size

> A double ballestron is a lot of work, cat schooners with self vanging
> booms are a much better bet, sheet loads are low, and reefing is
> easier.

If the sheeting is low enough, then I wouldn't bother

> Any time you have steering trouble with one rudder (light air is more
> likely than heavy in my experience) lower the front rudder as well.
> The boat will steer as if it is on rails. We sailed El in 10 knots
> breeze with 2 adults and 3 kids (250 kgs all up) with one sail and one
> rudder. Shunting and control were no problem, although it worked
> better with the fatties sitting on the rear beam. Pretty wet ride,
> though as there was not much beam clearance with all of us sitting on
> the ww hull.

That is good to hear. In light airs, I would expect the front rudder
to be needed a little as the bow has less sideways resistance.

I still prefer your squeeze and lean-on method over a mould for the
hull bow shape. I was just trying to avert as much hand glassing as
possible and it seemed easier to fair a single cut and shut rather
than half a dozen

For the top half of a wingmast, I've been thinking that basalt fibre
may be good enough as you are wanting more flexibility and it is a
wider section.

I was also wondering about making hatches using basalt cloth and some
carbon tow for the frames. My son is pretty good at making moulds and
thought it might be possible to make some moulds to make a nicely
finished job. It would be only slightly thicker than aluminium but
would be a bit lighter and when considering 8-10 hatches it may be
worth the effort. Have to check the thickness of the polycarbonate needed.

> regards,
> Rob
> On Mon, May 26, 2008 at 8:26 PM, Robert <cateran1949@...> wrote:
> > -For the top sides, a simple conic section with radiused edges would
> > surely be easier than strip plank. I checked out the pre glassed
> > poplyprop panels and they were a very reasonable price. Not that
> > different from what I could buy the materials for, let alone all the
> > hassles and the vacuum bagging disposables.
> > My idea for the bottom of the hulls is to have some 20' panels,
> > preglassed one side. glass to above the bilges, glass the middle
> > section together and then do some cutting at the keel and the bilges
> > to make the bow. It would go from round bilge gradually to a chine. I
> > don't think a chine would be bad near the bows as it would further
> > damp any pitching. If you wanted to, you could round these chines by
> > putting in some creases in the polyprop on the inside close to the
> > join All but the chine , the keel and the joins between the 20'sheets
> > would be fair.. If you wanted to , you could z jion the sheets such as
> > used with balsa panels
> > To join the bottom to the sides I was thinking of a stepped hull such
> > as Todd's model, only instead of a wide step, I would break it into
> > two steps. This can be done with a one sided glassed zig zag panel
> > made on the table separately, and having a bit of a concertina effect
> > to allow easier tolerances in the joining. After the joining , it can
> > then have its other side glassed and thus stiffened up. Joining the
> > deck or cabin roof to the sides, I would use a KSS method to make the
> > deck and topsides down to the bottom of the portholes, only having the
> > port holes where the cuts are , thus significantly reducing the
> > fairing, especially with a sponson to cover the joins. On the inside I
> > would have a big bevel with hatch large enough to slip through. It
> > would provide ventilation, a lovely view of the fishes, and a chance
> > for the galley slave to catch the fish of the day and to reduce the
> > time from the water to the frying pan. The extra width down below
> > allows an area for someone to get away and catch up with their
> > The sleeping set up has me vacillating, as I am tossing around whether
> > to make it easily trailable with telescoping beams to reduce it to
> > 3m-permitted in daylight hours with a wide load sign. or 3.5 m
> > -permitted with wide load sign and flashing lights. I was considering
> > flaring out the lw hull to 1.2m to give more bury for the crossbeams
> > and also to make a couple of cozy doubles in the lw hull. With the
> > flare out to 1.2m in the ww hull, leaves 1.3m wide shelf berth in the
> > ww hull. The other possibility is to have have the berths in the ww
> > hull stretch across the boat by having a slide out foot locker with a
> > neoprene flange to make it watertight. This allows a large saloon and
> > steering station at deck level or smaller saloon and narrower
> > Still torn between the simplicity of the single Ballestrom rig and
> > having a schooner rig for control in skinny water.-possible even a
> > double ballestrom rig to reduce sheet loads. This would allow the
> > booms to be a bit lower as there wouldn't be such interference with
> > the cabins and possibly close the gap between the sails and the top of
> > the lw hull, thus improving efficiency.
> > There is one small niggling doubt about the beam hung rudders. Clearly
> > they work and are far back enough as the single cat rigged Elementarry
> > with the single rudder forward of the beam performed OK, but my
> > thoughts are for when you are going to ww in thirty knots, there is
> > messy water causing increased resistance, reefed down to the main and
> > the ww hull is loaded to the maximum, will it still be far enough
> > back. It would be interesting to see El perform with an extra 200kg in
> > the ww hull. I suppose in the case of reefing the ballestrom rig, you
> > could reef by reducing the area of the main and leave the jib, or reef
> > the main further and remove the jib. This is a case for a roller
> > reefing jib. You could also make sure the crossbeams are as wide apart
> > as possible.
> > With deck mountings on the lw hull, you could have the beams wider
> > apart at the lw hull
> >
> >

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