Barge-Proa once again. Videos.
The barge shape has a large sideways stability. I don´t want the stability of the main hull to dominate the behavior of the proa to much so I want a wide total width. My red barge-proa is 143 cm long and 92 cm total width. I wanted to make it 100 cm wide, but that did not look “right” to me. That is a 1,55/1 ratio. 12/1,55 = 7,74 m total width for a 12 meter vaka.
I want the ama+aka to be light and wide, instead of short and heavy. A greater width and lighter weight for a given RM gives a greater mass-inertia - resisting capsizing from gusts, without adding access weight.
This is my view on this, based on my experience with my models. I know Sven Stephens has another experience, and I don´t want to claim he is wrong in any way. This might change when I scale the proa from 4 feet to 47 feet.
Cheers,
Johannes
Do you have an idea of a good beam to length ratio?
If you were to build a 12m main hull, how wide would it be?
Your question is the reason behind a lot of the discussion in this thread. Skinnier means faster with less room for accommodations. Wider means slower. At a certain point the whole argument for proas (fast, cheap, low effort) falls apart and the need for accommodations drives people towards catamarans and trimarans.
The barge form discussed here is being considered as one way to get better accommodation layouts with a shorter length. The crux of the matter is how badly the wide, boxy form increases drag and decreases performance. Johannes’ preliminary observations seem quite optimistic - performance seems good.
The real issue with proas isn’t defining a hull length to build, it is defining what accommodations are required and figuring out the purpose and usage of the boat. Once you know those items, it more or less defines length for you. Johannes’ idea may allow shorter hulls to meet requirements with less compromise than previously thought.
Many of the designs discussions archived here clearly outline L/B ratios for vaka and for amas. I’d hunt for designs that appeal to you and see what others have done. That’ll get you in the ballpark.
—
Bill S.
Don’t overlook the fact that the sailors from Oceania travelled upon their boats, not inside of them. When they built boats for extended travel they opted for designs with more voluminous amas and built shelters atop the connecting structure; druas as opposed to proas.
Perhaps we are again trying too hard to apply contemporary western solutions to a problem long ago solved in the Pacific?
Polynesia -> warm climate
Northern waters -> cold climate
How to get shelter from the environment while still keeping the benefits of the traditional proas.
The proa is on the extreme speed-and-price end of the triangular “speed-price-comfort, pick any two” scale.
If I did not have a family I would build myself a 60 foot slender and minimalistic deep-V wharram inspired proa. Something similar to one of the hulls from a Wharram Tiki21, but three times as long. I only need a 2 foot wide area to lie down in my sleeping-bag. A 10 x 20 inch area for my single burner gas-stove and a small locker for a couple of books, a bottle of wine and a small netbook, the rest is only there to SAIL brutaly fast. Once I get below the 40s parallel I don’t need much else.
Maybe a glass-dome ontop of the deckhouse to keep a lookout in bad wheather.
Cheers,
Johannes
Polynesia -> warm climate
Northern waters -> cold climateHow to get shelter from the environment while still keeping the benefits of the traditional proas.
Indigenous craft around the world were shaped by the synthesis of available materials, local skill sets, and the need to solve a problem; different situations, times and places result in different solutions. Perhaps a proa just isn’t really a great candidate for high-latitude cruising. It’s one of those “you can lead a horse to water” situations, I guess….
The question of “why didn’t the rest of the world think of using multihulls?” is often asked on these sorts of forums, and this dicontinuity explains why: they don’t magically solve all of the problems, nor satisfy everyone’s diverse needs. They are great for hopping from atoll to atoll to trade some bananas for clams, but they were never conceived to be lived in nor to haul tonnes of gear up a river.
For shelter the Polynesians built shelters atop their drua when they needed them, or dismantled them when they didn’t. I would think that a combination of long skinny sleeping spaces within the confines of the hull (or hulls?) plus the more open, ventilated, and adaptable shelter over the bridgedeck might work.
Credit: sketch courtesy of Aldo and Corrado Cherini’s collection
Polynesia -> warm climate
Northern waters -> cold climateHow to get shelter from the environment while still keeping the benefits of the traditional proas.
This is a topic I’m pretty interested in. I live above the 49th parallel in Canada and given my family’s stage in life (kid in school, mortgage to pay), I can’t just move where cold isn’t an issue.
I buy into the proa concept clearly understanding the compromises and tradeoffs. At this point, perhaps a new thread is needed because further discussion would detract from Johannes’ conversation.
I think there is a lot of ground to explore in maintaining the things essential to keeping a proa true to it’s roots, while also adapting to less tropical environments. Johannes’ thesis is that changes to the hull form may be worthwhile - and that is worth further investigation. I think there may be more things outside changing the hull form that may allow the proa to adapt to working for me. The good news is that we are looking down a road Russell Brown has already travelled - he a Pacific North West resident and they know cold rain better than most.
—
Bill S.
I had no intention of hijacking any thread, especially one that I’ve been encouraging. I was only pointing out that when the Polynesians needed a boat with accomodations, they built something other than a proa canoe… and I’m happy to leave it at that.
I buy into the proa concept clearly understanding the compromises and tradeoffs. At this point, perhaps a new thread is needed because further discussion would detract from Johannes’ conversation.
No, there is no need to start any new thread. I think this discussion about how to live aboard a proa is very pertinent to the barge-proa thread. The barge-proa is all about having some comfort in an easy to build proa.
I think this is very interesting.
Cheers,
Johannes
Russel Brown’s solution was a heater. You can see it in the video of JZerro sailing hard, with a cup of tea brewing atop to show how smoothly the boat handled the conditions.
Regarding “I can’t move someplace warm because I have a mortgage and a kid in school”, that’s a total cop-out. People in warm climates have mortgages and kids in school, too.
Russel Brown’s solution was a heater. You can see it in the video of JZerro sailing hard, with a cup of tea brewing atop to show how smoothly the boat handled the conditions.
Regarding “I can’t move someplace warm because I have a mortgage and a kid in school”, that’s a total cop-out. People in warm climates have mortgages and kids in school, too.
Wow, a Sailing Anarchy quality ad hominen response. Didn’t expect that here.
Whatever my reasons for not wishing to move, they are mine and not subject for further discussion on a web forum.
Mr. Brown’s solution was a lot more than a heater - and the solution solved a lot more problems than just warmth. Adding the leeward pod helped with capsize prevention and recovery, it gave a double berth to a very high performance Pacific Proa and he also managed to come up with a semi-enclosed seated bi-directional helm location.
He and his crew were able to weather three days of riding out an offshore Atlantic storm together in his cabin space - and that speaks volumes if it happens without getting on each other’s nerves. Reading through his father’s account of the trip from Bermuda to New England further leads me to think that my requirements can be met. Three berths, cooking space and storage in a proa under 37’ is notable - especially when the trunked rudders chew up a lot of space. John Harris’ Madness also fits the higher latitude regions pretty well.
—
Bill S.
Perhaps a proa just isn’t really a great candidate for high-latitude cruising. It’s one of those “you can lead a horse to water” situations, I guess….
Perhaps they once said the same thing about the Viking longboat - good for nothing but raiding. But it was evolved into some wonderful high latitude cruisers, over time. It’s interesting to me how the proa idea is attractive to people descended from the Vikings. I have an old book about ocean voyagers that starts the multihull section with a chapter called “Vikings of the Pacific”.
Russel Brown’s solution was a heater. You can see it in the video of JZerro sailing hard, with a cup of tea brewing atop to show how smoothly the boat handled the conditions.
Mr. Brown’s solution was a lot more than a heater - and the solution solved a lot more problems than just warmth. Adding the leeward pod helped with capsize prevention and recovery, it gave a double berth to a very high performance Pacific Proa and he also managed to come up with a semi-enclosed seated bi-directional helm location.
He and his crew were able to weather three days of riding out an offshore Atlantic storm together in his cabin space - and that speaks volumes if it happens without getting on each other’s nerves. Reading through his father’s account of the trip from Bermuda to New England further leads me to think that my requirements can be met. Three berths, cooking space and storage in a proa under 37’ is notable - especially when the trunked rudders chew up a lot of space. John Harris’ Madness also fits the higher latitude regions pretty well.
The only high-latitude modification was the heater, and having the autopilot mounted in the cabin so the boat can be steered from inside. JZero, Kauri, Cimba, etc. all have the other modifications even though they are not high-latitude boats. I don’t even see insulation on any of the boats, and it would be as welcome in the tropics as the arctic!
Regarding Madness, there is nothing about it that makes it better at sailing high latitudes / cold weather than the three other proas listed above. I’ve never been able to find a picture of it’s interior, but the plans show sleeping accommodations for four people, and nothing else. Not even a head or galley! I know they fit a port-a-potty under one of the coffin berths in the original boat. The limiting factor to its interior design appears to be the requirement of these berth flats to support the stitch-and-glue construction. Staying on-topic, Johannes Barge Hull might find itself in a similar predicament: requiring more bulkheads, stringers, or berth flats to support the side-panels which will only be bent in one direction and thus develop less rigidity than the cold-molded hulls. I suspect bulk-heads and stringers would be the better answer, and less intrusive as he’ll have the extra room to accommodate the intrusion.
Only JZerro has any specific equipment to combat sailing in cold weather. Equipment that could (and should) be fit into any boat expecting to do that, unless you’re abilities are on par with Beto Pandiani and his crew. ( http://www.youtube.com/watch?v=3r1WFtO0GIc Worth a watch, even though it’s not a proa.)
Regarding “I can’t move someplace warm because I have a mortgage and a kid in school”, that’s a total cop-out. People in warm climates have mortgages and kids in school, too.
Wow, a Sailing Anarchy quality ad hominen response. Didn’t expect that here.
Whatever my reasons for not wishing to move, they are mine and not subject for further discussion on a web forum.
It was not meant as an attack, simply an observation. If you’re comfortable where you live and have no reason to leave there, then why move south just to get warm?
It’s interesting to me how the proa idea is attractive to people descended from the Vikings.
I think that comes from all the skerry-cruisers, caneos, kayaks and old slender working boats from our lakes.
Below is a picture of the Hjälmarsnipa, which is the indigenous boat from the lake Hjälmaren in sweden. Does anyone see the similarity with the pacific indigenous boats and wharram double canoes?
All the slender boats are probably direct descendants from the stone-age dugout canoes that we used. As they spread all over the globe, they started to change and adapt to very different enviroments and available materials.
When I first saw a Hjälmarsnipa I was very very curious about it. I was told it was a fast row-boat, and that it was very safe and well behaved in the very steep nasty chop in the lake hjälmaren. It is probably a direct descendant from the viking longboats. It is usually 20 - 24 feet long and 3 - 3,5 feet wide.
Anyone sailing or using a slender skerry-cruiser or a canoe soon starts thinking about adding akas and an ama. It comes natural, since it is always fun to sail faster with a better stability.
I don’t think it is soo far fetched to build a very slender Hjälmarsnipa and add crossbeams and an ama.
Cheers,
Johannes
I will see if I have something to wind the retrieval
Cheers,
Johannes
Been out to circulation, what about one of these
Tink
(Finally deleted my user dictionary and stopped Tink in capitals)