Subject: Re: [harryproa] Re: harry gami.
From: "Rob Denney" <>
Date: 5/22/2008, 10:11 AM


Just posted the weights and materials spreadsheet to the "Trailer
sailor,see post 3348" file.

As you can see, the weight (415 kgs/913 lbs) is less than I estimated,
giving an empty Bruce number of 1.9, which is much more respectable..

Anything that looks like a mistake probably is, so please let me know.

Still cleaning up the drawing, and seeing if the whole thing can be
made from partially glassed flat panels, which will make it much
quicker to build and eliminate a lot of fillets and tabbing.



On Thu, May 22, 2008 at 9:23 AM, Rob Denney <> wrote:
> G'day,
> There are a number of ways to add to the bruce number. A longer mast
> is one, although this is harder to erect/remove and trailer. If you
> leave the mast building until after the hulls and beams are built, you
> will be an expert in telescoping structures and could go with a
> 15m/50' luff which telescopes to 8m/27'. Better in the light, and
> heavy and quicker to erect/remove. This would give you sail area of
> 41.5 sq m/456 sq' plus 6 sqm/64 sq' of mast . Total 47.5 sq m/510 sq'
> and assuming we saved enough weight to keep it the same, a Bruce
> number empty of 2.2, and loaded of 1.77 which is definitely record
> breaking material.
> Plans cost is the same as the 12m harry, $Aus3,000, which all goes to
> the engineer. The plans will show you how to build everything except
> the sails. You will get a 10% rebate from anyone who buys a set of
> plans between now and when the next one after yours hits the water.
> After that, if anyone buys one because of you or your boat, you get
> the 10%. Payment is 50% now, 50% when the plans are complete. This
> keeps me enthusiastic during the boring part of the design process,
> although there should not be much of that with this boat. It also
> allows me to improve the plans based on feedback from other boats
> without having to draw everything twice. I will send you bank
> details and some other stuff offlist.
> I will do some more work on the drawings and have some more exact
> numbers tonight, including the materials costs. Could probably ship
> the Polycore direct from China so it would not be any more expensive
> than buying it here.
> A racing hull is a good idea, but really only for day sailing. The
> hull drawn would be pretty much as small as any sane person would want
> to sail on the Great Lakes in. Plus, weight in the ww hull is not the
> big deal it is on cats and tris. It would be a pity to be freezing
> your butt off on/in a minimal hull that had to have water added to it
> to get enough righting moment.
> See you for the Chi/Mac next year!
> Regards,
> Rob
> On Thu, May 22, 2008 at 12:16 AM, captian_rapscallion
> <> wrote:
>> I really like the concept! I would build using your carbon fiber
>> approach, with the hope I add a bit to the bruce number. I believe the
>> limit on the type II trailer is 2500 lbs. Perhaps we should discuss
>> the plan details offline?
>> Also, do you have a rough cost of the build? I was thinking polycore,
>> or nidacore - polycore is better and cheaper but the shipping might
>> not make it cost effective.
>> And as for crewing in the Chi Mac, if you actually show up, I'll crew
>> and you can skipper!
>> And if I have any money left over maybe I can build a "racing" wwhull
>> just for the mac and key west. I was budgeting for a 31' KH trimaran,
>> and it was going to be very a tough build cash - wise. This boat is
>> closer to what I'm looking for (easier to launch, cheaper and easier
>> to build, easier to sail and should be a fun ride!)
>> Eventually, I would like to get a bigger boat in a warmer climate and
>> cruise, and a proa is perfect for that, so this will be a good middle
>> step in the right direction.
>> --- In, "Rob Denney" <harryproa@...> wrote:
>>> G'day,
>>> On Wed, May 21, 2008 at 12:03 AM, captian_rapscallion
>>> <captian_rapscallion@...> wrote:
>>> > Basically,
>>> >
>>> > I was thinking of a proa designed to be the ultimate trailer sailor/
>>> > racer cruiser. Although the boat will probably be kept in a slip,
>>> > (meant for a monohull) I really like the idea of a true trailer
>>> > sailor, meaning a sail boat that can be launched almost as easily as a
>>> > fishing boat. I think the Rio Hondo 40 is a good example of such a
>>> > boat. (it's a bit big, but I like his line of thinking.
>>> Think we can do a lot better than the Rio Hondo (11 knots reaching or
>>> running in 16 knots of breeze). Launching will be harder than the
>>> fishing boat as the mast has to be raised and the beams sorted, but
>>> both can be done quickly if designed for it.
>>> My ideal would
>>> > be capable of being pulled by an ordinary car. I was also hoping it
>>> > would telescope to about 8'6" for the trailer and the mast(s) would be
>>> > easily set up by one person quickly.
>>> 8' 6" is possible, the mast will take a couple of minutes to lift
>>> (with a gin pole alongside the mast) and insert. Quicker than any
>>> stayed mast to erect. The telescoping is also very quick, if it is
>>> set up properly. Makes the building of the beams a little more
>>> complicated, but all the tight fitting pieces use other parts as
>>> moulds and it is possible to dry run everything before final assembly,
>>> so it is easy enough to build.
>>> I'm willing to give up a bit of
>>> > performance for ease of setup and tear down. I live 5 to 6 miles from
>>> > the launch ramp. I really don't have a maximum trailer length, just a
>>> > weight limit (type II trailer hitch. Nothing weird to report about the
>>> > ramp.
>>> Should not need to give up any performance. I doubt there is 20 kgs
>>> extra in the telescoping.
>>> Solitarry is 15m/50' and weighs three quarters of a ton ready to race.
>>> Be pretty awful to tow, though, so let's say 12m/40'. What is the
>>> weight limit on a type 11 hitch?
>>> Trailerable width of 2.5m (8'3"), marina width of 3.6m/12' and sailing
>>> width of 6m/10' is easy enough with single telescoping beams.
>>> Leeward hull length 12m/40', windward hull length 7m/24'
>>> Weight of the shell (hulls, beams, rudders, rig) will be about 550
>>> kgs/1210 lbs. For the sake of discussion, I have allowed 400 kgs/880
>>> lbs of payload in the windward hull. It is easy enough to tweak the
>>> windward hull and or the beam overall for more or less weight or sail
>>> area. All up weight 950 kgs/2,090 lbs
>>> Sail area 26 sq m (main) plus 4 sq m of unstayed wing mast, (12m/40'
>>> long overall) =30 sq m/323 sq'.
>>> Bruce number fully loaded 1.4 Bruce number empty 1.7. Not a record
>>> breaker, but there would not be many trailer sailors that will be
>>> faster. .
>>> Hull flying wind speed empty, 5 knots, Full 15 knots (actually a
>>> fair bit more than this as the mast bends to spill the wind).
>>> Layout as per the rough rendering in the Files section. Finished
>>> boat would have radiussed corners on all panel joins, windows,
>>> hatches, a lot more detail, etc. I will get onto this when I get a
>>> bit of time, or someone wants to buy one.
>>> >
>>> > Accommodation: I was hoping for standing headroom and a fully enclosed
>>> > head, a very modest galley, sitting headroom for the bunks is ok. I
>>> > was just hoping for some more permanent than a pop top. The two week
>>> > trips would be once a year for 2 people. I'm currently doing such
>>> > trips with a laser 28. The boat would be located on Lake Michigan, and
>>> > will hopefully race there, (CHI MAC would be nice) I would also like
>>> > to take it to Florida for the Occasional Key West Race is possible.
>>> > Lake Michigan is cold and can get pretty rough, so it would be nice to
>>> > have a seat out of the cold in addition to the cockpit seating if
>>> > possible. I live in the fresh water surfing capital of the world to
>>> > give you an idea of how rough.
>>> Can do a cover over the cockpit easily enough, which will keep the
>>> wind and awater off, but I would make it folding (pram hood style),
>>> just in case you ever do get a sunny day ;-) Crew/wife can sit/lie
>>> on the bed down stairs if it is really nasty. Close enough to talk to
>>> the driver, but dry and warm. The galley space is the opposite end to
>>> the bunk. Lots of it, but not much is really usable. Probably put a
>>> divider across it with a hatch in the roof for access from outside and
>>> use it for storing batteries, fuel, fenders etc. The enclosed head is
>>> easy enough, but does not quite have standing headroom. The door
>>> and walls are not shown on the layout drawing.
>>> >
>>> > Gear weight for the trips would hopefully be minimal. I would be
>>> > stopping at Marinas in the evening for water and possibly fuel. I
>>> > would think 100 lbs of food and gear would be more than enough, and 2
>>> > people at 150 lbs each. I like the idea of an electric motor instead
>>> > of a gas one, simply because I have always fought an exhaust leak on
>>> > my laser 28. It would be nice to not have to worry about that.
>>> The Torqueedo electric motor may do the trick, as would a 5 hp (or
>>> less) outboard.
>>> >
>>> > As far as performance goes, I am hoping for a fast boat. I'm willing
>>> > to give up some speed to gain convenience, but it will spend most of
>>> > it's life racing. I simply want a comfortable ride while racing, you
>>> > know, for the wife :)
>>> Most of the comfort can be removed/replaced if you want to race
>>> seriously. Although, as it is all righting moment, it is less of a
>>> big deal to leave it there than it is on a cat. If you do the Chi Mac
>>> in it, I want to crew!
>>> Comments, suggestions, criticisms welcome.
>>> regards,
>>> Rob
>>> > --- In, "Rob Denney" <harryproa@> wrote:
>>> >>
>>> >> G'day,
>>> >>
>>> >> Sure can. I would use the same basic methodology as I am using on the
>>> >> telescoping mast on Solitarry.
>>> >>
>>> >> Harrigami was complicated as I thought the mast and ballestron
>> had to be
>>> >> raised and lowered with the boat on it's side. There are easier
>>> > ways. The
>>> >> 12m/40' cat 'W' that I built a few years ago had a beam which varied
>>> > from
>>> >> 4m/13' to 7.5m/25' and could be expanded/contracted by one person.
>>> >>
>>> >> I need to know a little bit more about exactly what your
>>> > requirements are,
>>> >> maybe email me off list (or on list if you want everybody to add
>> their
>>> >> sixpence worth) and we can discuss it.
>>> >>
>>> >> The questions are:
>>> >>
>>> >> Maximum trailerable length? This will be longer if it is a once a
>>> > year trip
>>> >> from home to the slip, and shorter if you want to use it as a trailer
>>> >> sailor.
>>> >> "Traditional slip" width?
>>> >> How often will you be trailering it?
>>> >> Are there any launching/retrieving ramp peculiartities?
>>> >> How much gear you need for two weeks? Either a list, or a best guess
>>> > of the
>>> >> weight will do for preliminary drawings.
>>> >> How much comfort do you need. ie, is a two burner cooker, sitting
>>> > headroom
>>> >> in the bunk, comfortable cockpit seats enough, or do you need
>> more than
>>> >> this?
>>> >> Motor requirements?
>>> >> Electrical requirements?
>>> >> What is your sailing area? More importantly, how sunny and how cold
>>> > is it
>>> >> likely to be?
>>> >> Any thing else that may be of interest.
>>> >>
>>> >> regards,
>>> >>
>>> >> Rob
>>> >>
>>> >>
>>> >>
>>> >>
>>> >> I also like the Seabattical design, not so much because of it's
>>> > looks, which
>>> >> are way down the list of characteristics I like about boats, but
>>> > because it
>>> >> fulfills it's requirements so well. The first of these was low cost
>>> > (very
>>> >> high on the characteristics list).
>>> >>
>>> >> On Tue, May 20, 2008 at 10:51 AM, captian_rapscallion <
>>> >> captian_rapscallion@> wrote:
>>> >>
>>> >> >
>>> >> >
>>> >> > I like the elementary design, and the harrygami design. I was
>>> >> > wondering if a design that had a cabin with standing head room and
>>> >> > accommodation for a two week trip for a couple would be
>> possible in a
>>> >> > proa designed to "fold" using a sliding mechanism that would
>> allow the
>>> >> > proa to be moored in a traditional slip and be trailered easily.
>>> >> >
>>> >> > I also really like the seabattical design.
>>> >> >
>>> >> >
>>> >> >
>>> >>
>>> >
>>> >

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