34 ft asymmetrical catamaran/tacking outrigger/cataproa

You're assuming your conclusion: "Everyone uses them because they're the best!" "Why are they the best?" "Because everyone uses them!"

This is what we call a "just-so" story. Ostensibly a plausible account of how something came to be. The problem is that "just-so" stories are often constructed after the fact, and often get the facts wrong. In this case, I think it might be more useful to simply list the advantages of a modern proa/outrigger. The cost of hull construction is still a significant portion of the overall build cost (which I would divide into hull, rigging/outfitting and interior). The other thing to bear in mind is the cost of ownership. Cost to store, maintain and operate are all still design considerations. There are some people for whom these are smaller considerations, but I'm simply drawing stuff that I think would be fun to build and sail with the money and family I currently have (or am likely to have to spend in the foreseeable future).

 

I'm not asuming anything. The people that created the sport catamaran in the western world started out on a tacking outrigger, and they knew about pacific proas also. It's simply a fact that once freed from the limitations of stone age materials the catamaran wins as an overall compromise. It is simpler to manufacture, offers better allround performance, etc. After all a catamaran flying a hull or a tri flying it's main hull behaves exactly the same as a pacific proa.

The pacific cultures that invented and used multihulls had a general progresion from catamaran to tacking outriggers to shunting proas. One culture evolved from multihull back to monohull. This is all related to specific local environment conditions.

I really want to hear what the advantages of a modern proa/outrigger are in your opinion. And please specify the size you envision because it matters. A 16 feet canoe is different from a 40 feet cruiser that has, fridge, shower and watermaker.
And please be so kind to include the metric you aply. If I gave you a stack of materials you can build a Tornado out of it or a hawaian outrigger. The Tornado will outsail the outrigger but the later can be paddled long distances. Your metric decides wich is the better boat.
Outriggers and proas have a place but their roles are very specialized and one has to be pretty clear about ones expectations. Horses for courses as they say.

 

Hello there. .... Interesting thread. I hope y'all don't mind if I join, and share a brief comment.

My name is Peter Mirow (don't ask me why the Forum didn't accept my registration with my real name - I have no idea), and I am the designer and builder of Arpex, a 30ft. tacking outrigger. During the research and design phase for Arpex, I have participated a lot in such forums, to bounce around the ideas for my boat. So, I might even still have a few friends here.
...
Designing, building and sailing Arpex has been an amazingly satisfying and fulfilling project, and now, four years after launching, I am still grateful for having had the courage to go, buy a pile of wood and pots of resin, and start building. Every time I lay my eyes on Arpex, I smile. I absolutely love every moment I set my feet on it. And sailing.... ah... sailing it, is just lovely.

A boat design and build project is a deeply personal experience, and so should be the outcome, a unique and personal boat. Why would you go through all the effort, if in the end you have something like everybody else does? It is much easier, quicker and financially wiser to go to ebay, buy a used plastic boat, and go out to have fun on the water. Which is a very valid way to have fun sailing. However, if you want to design and build, you've got to love the process of designing and building. You got to enjoy the research, the discussions, the experimentation, the dust, the sweat, the problem solving, and, yes, the risk. Because, make no mistake, there is a considerable risk to end up with a mess. But if you manage to get through all that, the moment you put your boat into the water, will be one of the beat moments in your life. No matter if it is fast, beautiful (it will be in your eyes), cost effective, or whatever measure you will put on it. You will just love it. Even if, of course, it will take much longer than you have ever anticipated.

And for heaven's sake: Don't care too much for what the other say! Make sure you discuss a lot, before you commit. Take in all the opinions. The positive and the negative... Be careful enough to listen to the critics. Benefit from others experience. I believe I did, and I thank them all dearly. As I mentioned, I have made many friends from all over the world during the process. And I have had the great privilege of even having a chance to enjoy sailing on Arpex with 2 of them. People often ask me, how I have endured 7 years of boat construction. And I reply: Oh, boy, ...I was having fun!

 

Ah...and... I recommend that you try and build an exact scale model, and make it sail. If you succeed, and if it looks good to you, you have a reasonable chance to have a successful project.

 

I think for those who don't enjoy the process of designing and building this may be a hard point to grasp. I think you made an analogy with the artistic process on your blog, and I think in many ways that's apt. Of course with most art the investment is primarily one of time (with the possible exception of architecture), whereas with a boat there is significant capital expenditure. I actually think this is a real growth area for sailing is to reduce the cost of experimentation (both in time and financial cost).

Bonus points if the scale model is itself fun to sail!

 

Just started reading Nature of Boats and Dave Gerr calls it "Boat Noodling"

I've been reading a bit on pacificproa.com but with all the pros and cons and the differences between pacific, atlantic, harry proa and tacking outrigger you really need a good metric for comparison. I think maybe the weirdness, all the new unknown design problems to solve and complications of an asymmetric hull and lend themselves to frustration.

For example about the interior layout. Apparently it's somewhat tricky. A proa does offer less space than even a smaller catamaran. You have a mast in the middle of your hull. But the compactness and the asymmetry might allow better use of the space. Building the cabin on top of one hull instead of in the middle and then having to connect both hulls should mean less overall surface area. You kind of get a larger bridge deck since one side is cabin and the other is open space instead of a cabin in the middle.

The most minimalist cruising proa might be a long T shaped hull. Something like a 50' long (15m) slender hull that is 3'3" wide (1m) and high, with a T bar on top that is 10' (3m) wide and 3'3" (1m) high. The height above water would be pretty low. You could sit comfortably in them and build a seating arrangement around the mast maybe, or put a fridge or bunks on top of it.

I've attached two quick renders but my CAD skills aren't very good. I'm not planning to build this exactly it's just for fun and I realize it's not very pretty or really any different from a pod proa. I'm not planning to build this, just for practice



You'd have a long hull that you can use as a comfortable walkway with standing height that extends above waist height inwards and outwards to get bunks or table top space. Maybe move the mast a bit leewards, that shouldn't hurt strength.

In terms of hull / wall surface / material costs / time to build you'd probably get significantly more out of this than a catamaran. With symmetric hull ends and long straight parts you could build molds pretty easily and use vacuum infusion foam.

 

Starting with the small boats. Materials for a 20' Tornado would build a 32' lee hulled proa with an 8' windward hull. It would be single handed for max performance as it could be a lot wider with a single beam (no tacking or wracking issues) with an easier to handle rig. The ww hull would float with the decks just clear of the water with the crew sitting on it. When sailing, it would be flying, same as the T, but at lower wind strengths. The lee hull would be lower and narrower than the T as it would have more pitching resistance (due to being longer) and be lighter (each crew is about 30% of the all up weight). In a straight line, it would be no contest, the proa wins by miles.
The proa would shunt a little slower than the T, gybe a lot slower. If the proa had the work, money and brains applied to it that the T and it's siblings have over the last 50 years (remember trying to tack Hobie 14's when they first appeared?), the proa would be fastest around the track.
If that is too radical, 25 years ago I build elementarry Elementarry – Harryproa http://harryproa.com/?bwg_gallery=elementarry a 25' proa with the same weight and sail area as a Tornado. Despite being rough, poorly tuned and badly sailed it was as quick as the top T's (world and national champions) around the track.

Cruising size harryproas are the most boat for the least money. They include so many things that are not used on cats (unstayed masts, steerable daggerboards, no headsails, self vanging booms, etc) and there are so many things on cats that are stupid (raised helm positions so you can't see ahead and to leeward, daggerboards, exposed props, multiple extras, 3 stay rigs, etc), that a comparison is pretty pointless. Check out . Weighs 3.3 tons ready to cruise, sails at windspeed without extras. C ompare it to any 15m/50' cat with 2 queen size berths, 2 singles, table with seating for 6, etc and ask me any questions which you may have. That is the first harry launched, 20 odd years ago. Development since has been continuous and extensive. The rudders are now less draggy (they can still be lifted and kick up in a grounding or collision), the rigs are bigger, the bows finer, the boats lighter (Custom 20m/65′ – NORWAY – Harryproa http://harryproa.com/?p=726 is a 20m/66'ter on target for 4 tonnes ready to cruise) and the build technique far quicker, simpler and cheaper INTELLIGENT INFUSION – Harryproa http://harryproa.com/?p=1845

Dejay,
Looks nice, but what stops it falling over? Would you ever sail a cat or tri sitting on the leeward hull? It would be more comfortable, have more usable room (no mast, rudders, boards or their support structure) and more righting moment if the cabin was on the other hull.

The hull assymetry inbalance is no more noticable while sailing than it is on a beach cat when you fly a hull. ie, not at all.
Different length lee hulls (tacking outrigger), will never be as efficient as always having the long hull to lee. The short hull will increase the risk of going over diagonally.

 

Hello Rob, I love your designs and concepts!

I have no experience or actually that much interest in sailing, I'd just like to build and thraven travel around slowly in a roomy liveaboard cruiser. Something like a 36' power catamaran.
But honestly your design with the unstayed mast and the straightforward "simple" rig makes me consider sailing after all. It seems like it would be much less work and doodads to sail. So I'm boat noodling, trying to figure out what designs could make sense for me

I love your concept for "max boat for minimum material / work" and intelligent infusion. It seems to have lots of advantages. Saving time, saving material, saving costs, straight walls and floors, furniture fit in, no sanding! Lots of brilliant ideas in my humble opinion.

To answer your question, I have no idea how stable it would be and with how large a sail, since I have no experience sailing. Probably you would need to shift ballast or increase the beam over all and rely on emergency buoyancy at 45° heel like the pod proas (did you mean this one with "pod proas"? Sorry my earlier link was fudged). I figure a smaller rig could work too?
If performance isn't of primary concern maybe that design could work well just to have enough living space for a family with the minimum amount of boat. Maximum utilization of a long hull as a corridor with space left and right to put things. It's a bit weird though. One advantage would be that it has lots and lots of flat space for solar panels (3x4 320 watt panels) on top.
Not sure if you'd actually gain any space compared to your cruiser 50 design, and you'd still want to add a cabin on top with my design. Just trying to visualize what could work and why.

One thing I'd like to ask:

I can see the advantages of "balanced weight and accommodation to windward" you list on your site. But if you DON'T want to fly the hull while cruising, how much of the displacement of the smaller ama can you lift and thereby shift on to the larger vaka?

What is the difference between lets say 80/20 weight balance on a pacific proa that has less stability, therefore less sail but has less immersion and resistance on the aka, compared to a 50/50 balanced harry proa that has more stability, can have more sail up but doesn't lift the aka that much so has more water resistance.

Is it a wash? Does the harry proa have more "remaining stability" when partially lifting the ama for the same performance?

 

Oh, yes. Indeed. I had great fun sailing my 1 x 10 scale model of Arpex. Great risk mitigation strategy, I think.

 

Thanks.

Much less of both.

Cool. Let me know if I can help.

Thanks again.

Can do, if your idea of fun is lugging anchors and supplies back and forth every time the wind strength changes and/or suddenly heeling to 45 degrees or more before the pod acts.

At the expense of speed in light/medium air, which is when most sailing is done.

It is not an "if". You categorically DON'T want to fly the hull while cruising. At the time the hull leaves the water, righting moment is maximum. Any increase in wind (either true or apparent from an increase in speed) will cause it to keep heeling unless you change course or ease the sheet. Sailing like this is for racers, not cruisers.

Until it flies a hull, the 80/20 and the 40/60 proa will be similar, given the same weight overall and sail area. For various reasons, the 60/40 will be lighter for a given accommodation, but will have more righting moment. At a given breeze, the 80/20 will fly a hull. At this stage, it will probably be quicker, although there is not much difference in drag when a proa flies a hull, as witnessed by the lack of noticable acceleration when it happens. From then on, the 40/60 will be quicker as it does not have to depower.

 

Ah thanks, that makes total sense. Increased sail power far "outweighs" the windward hull.

Hmm. I wonder if the wave resistance near the "hull speed" of the smaller hull could also be different that what you'd expect from a equally short monohull or catamaran.
Normally you'd expect a shorter heavier hull to have a harder time climbing up on it's own bow wave or pushing through it, but in this case the larger asymmetric hull could help push it over more easily, keeping the shorter hull level instead of squatting. The shorter hull basically transfers some of it's weight to the larger hull through the bridge beams.
There could also be beneficial wave interaction, where the bow wave of the larger hull maybe provides a bit of lift near the end of the smaller hull. Godzilla would probably optimize the length and distance of the second hull for that.

Anyways, just speculating. So much to learn, so much to figure out yet! I'll definitely check out your elementarry v2.

 

Hello rwatson,

Sorry, I couldn't resist to reply. I read this comment a while ago. But it always comes back to my mind. So, I thought, I might offer some comment. To go with it, I would like to invite you to watch a few of my sailing videos. They give a fair picture of what it is like to sail Arpex. And one could say many things about it, but not, that the crew would suffer from exposure, in any way.



You see, Arpex, my boat, is designed around a very specific deck & cabin layout. I wanted the free open space that you need in the tropics, good working space for sailing, with a great wooden deck platform, for lovely swimming activity, when at anchor. And I wanted a really well protected helm position and cabin area, where my wife could rest in comfortable shelter, while still being part of the trip by having a clear view to the outside, and with direct contact to the helm person.

My motivation was the following, I started by building a small outrigger sailing canoe. It was fun sailing, but rather tipsy. So that taking my girlfriend for a ride was a bit risky, and uncomfortable. So, I had to build a bigger boat.

Arpex can be sailed from the nice open deck, just as well as from the total shelter of the cabin. From inside the cabin, I can steer, and I can reach, and release the mainsheet. With perfect visibility conditions all around, and good ventilation. When I stand inside the cabin, my head is just outside of the hatch, and my arm comfortably reaches the wheel. I can also sit on the entrance platform, and close the hatch. Then I will steer in total protection. It is made to my measure. And I can steer while heating a cup of coffee on a camping stove, too. Or grab a cold beer in the ice box.

My girl loves to read while I sail. She will usually do it inside, resting on the wide cabin bunk, with good light, and a nice view forward, and on the same height as myself, on the helm. Protected from wind, rain and sun.

It is a perfectly safe boat. Also, because it steers itself quite happily. While singlehanded, I can walk around the deck, tend to the halyards at the mast, the sheets, the cup of coffee, or just go enjoy myself, while the boat works. I can enjoy the scenery, or do something important. I know no other boat on which I can do that. Of course, if you install an expensive auto-pilot. ... The deck offers comfortable seating positions, either in the lovely breeze, or else in shelter, behind the steering console. There is a bimini cover too, to protect from sun radiation and rain. It covers the helm seat, forward seat, and hatch area. Spray seldomly reaches the deck. It is dry sailing.

The ama offers enough reserve stability. It starts skimming, but never lifts. Not in our conditions here. You never have to go out, hike the ama.This is not a racing boat. I have sailed Arpex in 18-20 knots with full sail, going upwind at 9 knots. My crew was comfortable and safe. Should the wind increase above that mark, I can easily reef. I can actually emergency reef in a second, by releasing the gaff halyard. It will depower the main immediately. In an emergency, I could also put ballast into the ama. But it has never even been close to that. And likely never will. Several watertight compartments make the boat unsinkable.

Riding on the platform is like flying on a magic carpet. Really good fun, and my girl loves it, while suntanning. Guests can rest there, while I operate the boat, and they don't have to move. Which is a nice feature on a boat.

So,... it defies logic? Maybe. I don't know. It's just my logic.

 

Since I have come back to this thread, I might also try to add something to the original design, which started it.

Considering that my boat, Arpex, is quite similar, except for the bridgedeck on the ama, I'd like to comment, that Arpex sails considerably better, the less weight, and windage I carry on the ama. As matter of fact, if I'd change something on the boat, I'd build the ama about 10-15% lighter. In my experience, weight and windage on the ama have a negative impact on maneuverability, under engine and sail.

You have to consider, that the asymmetric configuration, with only one rudder under the main hull, does bring implications on how the boat maneuvers and behaves, since the rudder pressure comes from one corner of your hulls buoyancy, and lateral resistances, and windages. Something to be considered, in different current and wind conditions. Also while sailing, the added windage will not improve your performance. The asymmetry requires getting used to.

 

The lack of logic is the crew on the Lee side of the boat. You obviously don't put any real pressure on your yacht to get performance out of it.

Let me know when you have film where the waves over 3" high

 

It depends on which performance you are talking about. As described, my requirements have been achieved in performance of crew comfort, which is the point you were talking about.

In terms of sailing performance, I have also achieved my targets. I sail at about 70-80% of the true wind speed. Means that in the average wind conditions of my sailing waters, the bay of Rio de Janeiro, of around 8-12 knots, I usually sail at around 6-8 knots. If the wind pipes up, I can sail at 12 knots. I am quite happy with that performance. As said, this is not a race boat. And, of course, this is a boat designed for the conditions which we experience here. It includes swells, which can be 2-3 feet or more, outside of the bay, and I have sailed in that. And specially steep, short wake waves, from passing powerboats, or ships. I have videos with that. But it is not very dramatic. Also, waves don't show well on video, as you know. ... I will not sail the boat into beach swell, of course. It is not a beach cat.




The videos above show the boat in a bit more of wind, from the second half on.