Post your design ideas

The tgull 2300 (with the new moon amas) and Argo had a hard time tacking in a chop. The tgull couldn't tack at all at times. Which is why Dick quit using them. At least one tgull replaced the new moon amas that I know of.

I also heard argonautica was very slow, this opinion can from the guy who built them in the 80s. The sumersault 26 was much faster...

 

Ok,

Here is a more refined asym ama design. This is what I sort of had in mind.

Like the W17, I was thinking flat side out, and when the ama is pressed the flat side would be perpendicular to the water.

 

I'm more of a beachcruiser really, but love the thought of a pretty quick multi built for very little competing with some big boys.

Dan

 

I think that look nice Rapscallion. What i dont undertand is why some discuss asymetric amas to be used instead of a foil(s)

 

===============
I'd lean to a low wetted surface ama hull design and use foils for lateral resistance and vertical lift-much better having a foil do that kind of work from a performance perspective.
I'm experimenting with a planing ama on a 12' ,very powerful tri but it wouldn't be good for a larger boat unless some sort of variable geometry was incorporated.

 

I haven't gotten to the foils yet... I'm still working on the hull shapes....

 

Lately I have being assessing my future , what kind of boat I really
need .and it occurred to me that there are a lot of us retirees out
there who would like to travel the world while we still can. I have
sailed and cruised for most of my life and have always been disdainful
of those road Gypsies in there RVs and mobile homes that
battle the highways all summer .But upon reflection I have concluded
that perhaps they have got it partially right. I think whats needed
is a boat that can function as a cruiser, that either a budget
conscious retired couple and occasional guests, or a young couple with
two children can tour the world, both land and sea,or as a day sailer
capable of taking eight passengers at speeds up to 20 knots. It must
be trailer able with small SUV or van.( load less than 6000Lbs ) Boat
and vehicle could have a symbiotic relationship ( charging storage,
tools Who knows ?) The boat and trailer must fit into container.
.(drive in drive out)The boat must fit in standard slip of less than
30 feet, be beach able as well as anchor and motor in less than two
feet of water. It has to be capable of cruising for a month at a time
( freezer refrigerator adequate water and fuel). All systems must
operate when the boat is on the trailer as well as in the water. The
boat would in fact convert to an RV for travel to inland destinations
( camp grounds , land locked seas and lakes). Boat would to be as long
as possible for comfort and speed .If possible an inside steering and
navigation station and stand up hot water shower would be nice (no
tents). It must be reasonably priced and easy to maintain as well as
sail. I guess the farrier 27 comes closest to my wish list and judging
by the number sold There must be considerable interest in trailer able
cruisers. There is also the warren 35 Maine cat .I like it but its not
really made to transport routinely. At any rate I have decided to
attempt to come up with a design that meets my criteria . I must say I
have been discouraged lately after reading another thread on this
forum "Can anyone design ?" but I am continuing as much as for my own
entertainment as anything else and with the intention of pursuing
professional help with the engineering if I can come up with something
that seems doable So far I am working on a folding multi hull 45 feet
long with a 27 ft beam that folds in the water and will motor at
slightly less than 27' by 8.5' and can be reduced to 22.5' by 8.5 for
transport so that either the boat trailer and towing vehicle or two
complete boats will fit in a 45' cube container. Projected all up
weight of the unloaded boat is about 3500 to 4000 lbs. Bridge deck
clearance is 4'. It is sort of a weight to windward proa but not
really. The hulls would have a length to beam ratio of 22 to 1 with
the longer wider leeward hull having more rocker( boat remains level
under power and at anchor even though more weight is carried by
smaller hull) It would powered by two Sanyo double sided panels that
can produce almost 600watts coupled to four p1800 Odyssey batteries
and an azimuth drive( 48 volt) all located in the fixed portion of the
windward hull along with a honda 3000 generator,two propane tanks,
instant hot water heater and water pump .The head with stand up shower
(pop up top) and galley would be adjacent and inboard between the
beams( all wiring runs would be short). The head would be an
"Airhead"(compost type). The sinks and shower would drain directly
over board ( no hoses or long pluming runs). Further inboard would be
the leisure cockpit , one of the three settees converting to a
covered double bed. In board again is the nav and steering station
stand up with sliding hatch open and sit down hatch closed. The sail
can be reefed and dropped from steering station. Adjacent to the
Leeward hull and under the rig is a covered queen size bed. I don't no
what to call the rig. Its kind of an articulated double Gunter or
dipping lug or maybe a sliding lateen , at any rate it cants to
windward close hauled and is upright off the wind. Hopefully it should
behave like a windsurfer rig. The idea is that it would be easy to
reef.( drop sequentially the Gunter sections then the sail and the
mast becomes a wing which constitutes the third reef).and could be
stowed for transportation on the trailer under the boat. To facilitate
shunting the rudder is mounted on circular tracks around the foot well
of the nav station and provides most of the lateral resistance and
lift to windward but even when lifted for shallow waters the
asymmetrical Leeward hull (flat side out) should provide enough lift
to sail to windward. Because the leeward hull slides forward the
center of gravity moves aft and the projected leeward bow increases
buoyancy forward so there should be less danger of pitch poling and
less pitching motion altogether. As an after thought I have put a
curved "lifting foil in the leeward hull. Initially I thought a
lifting foil would have to be farther forward to be effective and
since it would have to be symmetrical for and aft its effectiveness
would already be compromised. Add to that an inability to auto retract
with an inadvertent grounding and I didn't think that any potential
benefit would be worth the added complexity. I have not really changed my
mind but the ability to adjust the center of lateral resistance by
other means than the angling for and aft of the rudder could tip the
scales. Its hard for me to describe what I am contemplating but
hopefully the attached renderings and animation will help. Any Ideas
especially about construction and saving weight would be appreciated.
Feel free to advise me on what you think absolutely will not work and
what might. I am going to Canada to sail on my boat for the next 5
months and intend to build a one sixth scale RC model of a working
design if I can come up with one. I apologize for the long post.

 

Timothy: WOW!

 

Jesus Timothy!
That is awesome!
I love the reef able rig! and the concept. I have always loved proas, and want to build one after the trimaran... but like you, I want to start small and work my way up in size. But, Wow!! is that a beautiful concept. You know what would be really crazy? Is if you could design the camp cruiser boat to "carry" the car with you at sea! Fully self contained obviously, not feasible... I only said that because it seems you have thought of absolutely everything else already!! Well done!!!!!
Perhaps I won't be building a wharram cat in 10 years afterall

 

That's a lot of very interesting ideas. My only suggestion would be to design a small working version of the boat, rather than a model, so that you can see how it works from the inside out. You might be able to build a one-man version of the boat at 16-19 feet or so.

But whatever you do to prove the concept, I'll be very interested to see how it goes.

 

Like this?

Dan

Sorry, It's just a little poke in the eye;-)

 

Its not for me but I like it. It certainly exploits the symbiotic relationship of boat and tow vehicle, and is light years beyond my effort in terms of styling ,space and creature comfort, although I suspect there would be a significant penalty in cost, weight, fuel economy, and performance. Nor does it appear to be a project for the home builder. I like to sail. It is my hope that I can do so well into my advancing years. Rather than like so many others in my age group make the decision that sailing has become to much for me and buy a trawler, I would like to explore other possibilities. If something like what you have illustrated was available at a reasonable price and provision could be made for a sailing dingy I for one would be interested.

 

The Argonauta intrigues me. On one hand I find the look of it off putting, but I'd love to have a sail on one just too see how the whole thing works together as a concept. Newick sells plans for a similar boat called the B2, with an optional lug rig.

We were fortunate to have Dick Newick give a talk at our yacht club last year. I asked him about the new moon amas and why his newer designs didn't have them. He said generally he thought they worked well, but were expensive to build and looked odd, which put people off them. The discussion was more related to his larger designs though. I see the new strip version of the Trem doesn't have them. IMO it is unfortunate the recent folding Tremolino redux as a production boat didn't work out commercially, the boat looked like a winner.

 

18ft electric power cat

I'm in the R&D phase of my new project. my idea is to power the cat with two water pumps mounted inside the hulls. originaly i'd planed to run it on petrol water pumps, but these were bulky and difficult to start then had to figure out how to attatch a throtle cable + venting + cooling= too hard. So im going to go with two electric pumps in the hulls and one generator mounted in a compartment on the deck. The only thing im not sure of is what size pump ill need. i've been looking at some 1200w pool pumps whitch put out 23,000 lt/h each but im not sure if that will be enough. i know it'll be no speed machine but i'm not sure if this will be worth while. any input or ideas would be greatly apreciated. Bowen

 

Timothy,
All looks doable, apart maybe from the 20 knots and some of the weights. Write a spreadsheet with all the weights and costs and see what you get. Err on the heavy side for anything that is not a "normal" boat fitting.

The rudder set up seems complicated (may not be, need more details), but I steer my 25' proa with a single rudder 33% of the length from the ends and no daggerboards so yours should work if the mechanism is correct. Be aware that at low speeds, the single element steering moves the boat sideways as much as turning it. I get round this with a second rudder at low speeds, you may need to use your motor, or move your rig.

I have not had much success with stayed proa rigs, but have not tried one like yours. The 'killer' problem with the strut and/or stays is when you get caught aback or accidentally gybe. Pretty rare, but it only needs to happen once in a big breeze and it all falls down.

I have just drawn a boat with hinged beams, there would be no engineering problems with building hinged hulls, except the ends are not accessable from inside, the side of the hulls has to be vertical and a fair bit of extra material has to be accurately applied. Making the beam and hull integral with removable ends for trailering is what I did on my (unbuilt) C class proa design.

The lightest (probably not the prettiest, but with flat sides, this won't be a problem) way to build the hulls will be as infused flat panels, with integral joins. We are building a small 15m/50'ter that will weigh half a ton empty and costs $35,000 plus rig. The cost is a direct reflection of the small amount of materials and how easily it can be built and put together.

I don't understand the "lee hull moving forward, cog moving aft" bit and I doubt it will justify foils.

An RC model will be a lot of fun and will be of some help, but I think your problems will be in achieving the weight, and making the systems work. The latter may not be provable at small size.

If you want any advice on scantlings or what I have found to work on weight to windward proas (which yours may not strictly be, but it will behave the same as one), please ask.

rob
www.harryproa.com