Raidboat Pacific Proa

If you want to know anything about Harryproas, either ask me (harryproa@gmail.com) or join the Harryproa chat group: HarryProa@groups.io | Topics https://groups.io/g/HarryProa/topics
where Rick Willoughby recently analysed the Harryproa set up, explaining why "The two large rudders near the beam give very close to ideal balance",
"Another thing that I find nice in operation is close proximity of the two helms so both rudders can be used simultaneously",
"When a standard HP is lifting the ww hull, the drive and drag are essentially aligned but there will be leeway if only the back rudder is working. It needs both rudders working to negate leeway. When the windward hull is loaded, it is pulling the boat to weather so the aft rudder has to pull the aft end to weather thereby reducing or negating leeway. There is a position of perfect balance for any particular conditions. "
and a bunch of other observations from sailing and analysing an 18m Harryproa

The forward rudder is not locked in position, although it can be. I have found the easiest way to steer upwind is to lock the aft rudder and steer with the front one. Reaching, use the aft one and downwind, lift the front one and as much of the aft one as you need.

A board will make it harder to shunt, as it cannot be aligned with the water flow, so stalls, creating drag. 2 large, liftable, kick up rudders is the best solution.

Any other questions, let me know.

 

Thank you Rob, this is hugely helpful. I have begun poking around the HarryProa discussion forum too, so thanks for the link. I wish I had the time and ambition for a larger project with IntelligentInfusion, but I currently dont even live next to a state that is next to the ocean......so for now I have to stick to my small boats and mountain climbing.

I hadnt thought about steering with the forward rudder, and the idea that the drag from the windward hull makes some turning moment and weather helm is not something I had thought about either. Seems to me a multihull, and particularly a proa, has a more complicated dynamic of helm balance than a monohull heeled over. Figuring out when it is advantageous to lock a rudder, or leave it free, or steer with one or both rudders will be part of the sea trials and practice I need before committing to the Everglades Challenge. Learning to sail in a new way with my proa is going to be fun and interesting.

For my proa, I have cannibalized a Hobie 16 rudder assembly, and the only challenge I see to this is the shallow water and frequent kicking up and needing to quickly and easily re-deploy. So the pressing question I have is about the placement of the rudders on the leeward hull.

Do you think there is an ideal distance between the rudders as a percentage of the hull length? Certainly the HarryProa rudders are not mounted on the end of the bow/stern (100% of hull length), but your rudders look farther apart than dividing the hull into 3rds (33%). Im planning on a 21' (6.4m) leeward hull for my proa. I can conveniently place the hobie rudders about 12' (3.6m) apart, making the distance between the rudders about 55% of the hull length, though I can close the distance between the rudders with minor modification to the platform. Just wondering what your thoughts on rudder placement and helm balance.

Right now my rig is looking like a pair of lugs, and I am absolutely sold on the schooner rig. Though Im sure many will scoff, my love for lug rigs has only grown with the 125sq ft mainsail I have for my yawl. A balanced lug rig to me looks like a lateen with part of the luff cut off, making it easier to reef. We'll see how it all comes together.....

Thanks again for the ideas and passion. Were having a gnarly snowy day (slow) at work, so planning to really get to reading the HarryProa discussion forum.....

 

Different rather than complicated. And less dynamic as the loads and directions stay pretty much the same unlike a heeling hull.

Depends on the rig (schooner is more verstaile), windage, the load on and willingness to fly the windward hull, the rudder size and ease of lifting and the agility of the crew. 55% apart is as good a starting point as any. Helm balance should be a touch of weather helm.

 

I started building my shunting outrigger canoe in earnest in May. Started with the ama, not sure why. About 2 months of tinkering in the garage for the ama to be 95% complete. It weighs 64lbs, has space for my 7gallon water jug and my anchor. I doubt I'll need to shorten the braces but I may depending on how the hulls ride together
- 16' CLC night heron double ender made with 3mm ply
- Monocoque shell glass inside and out, i left a couple glassed bulkheads inside. It's full of xps foam. And has a couple drain holes for air circulation

The canoe is 4mm ply bonded to 11mm plascore sheet. I bought a pallet of panels 10 years ago and have slowly used them. Canoe also has a significant amount of catastrophe foam under the floor mostly toward the bows. The middle space in the bilge under the hatch is open for some gear, heavier camping stuff. I plan to launch first and be sure that loaded with gear the floor is above the waterline and then I'll cut a few drain holes to avert the need for any bailing. Hull will get a 2"thick layer of foam on the bottom to radius the corners and fair it out. needs glass inside and out and i have a piece of kevlar to go on last for the hull d, so i won't cringe sailing up onto a beach.

Im still devising the rig and beam attachments and floor, i have twin lug sails and all the spars. My aluminum tube masts are too thin to freestand, so I have learned lots about splicing dyneema for the bows stays and windward stay.

Ive upload pictures from my phone which is a hassle so the order is messy.

 

very well done, dont forget that if you try the shunting rig and it is too difficult, you could convert it to a tacking rig. Just add a little weight to that ama (water jug) and you would be set. Note that I am biased having a website on tacking outrigger canoes

 

Did you really put all that foam in the outrigger?
Do you know what the foam weighed?

What kayak design was the ama made from?

 

The kayak design is a clc night heron. I made 16' panels for 2 bow sections.
The foam was a sheet and a half of pink home depot xps foam board insulation. I doubt a panel weighs 5 lbs, so im guessing 8 lbs total.

Your first question is rhetorical, but I'll humor you. Yes, what I'll call catastrophe foam fills most of the volume of the ama. Im guessing it's unlikely I'd ever crack a seam in the hull hitting something hard, but if I did it would likely sink, or suck bad anyways with it half sunk. The outrigger is but a shell.

And I'm building a shunting pacific proa. A little mass in the ama only helps my righting moment. The night heron has 300lbs max payload, so a jug of water, some gear, 64# of boat, and my skinny butt doesn't come close to over loading it.

 

Mr. Upchurch, what swab-built boat is ever "done," as you put it...?

My rig sails fine, but finished? Needs outrigger made of foam and the main hull needs to have cockpit, to make paddling easier...also, since spars are carbon, might later alter the attachment scheme...using hook and loop now...maybe add lazy jack to keep Dacron dry...life is good...

I have perused OPs plan and it seems solid, save proa part...might steer him to using older hulls and a more conventional plan...like a MO.

 

Im closing in on being finished with the canoe. Multiple layers if glass cover the xps bottom foam, then a layer of kevlar and a final layer of glass for fairing.

The exposed plascore edges have always annoyed me. The ca oe is stiff enough with the glass and kevlar inside and out that i didnt think the additional weight and structure of the gunwale was needed. I cut schedule 80 pvc electrical conduit to cover the top exposed edge and I really like it.

Its down to rigging, dry fitting hardware, figuring out lashing and the structural connections, and mounting rudders.

 

The proa DAIKON sails!

Got out shunting, what a blast. Finally had a first day out sailing, Now I can say Ive shunted a proa a few times. Got him rigged up and working, full sails up for the first while. Didnt quite fly the ama, but I can feel it lift. I was a Chatooga River guide, I can high-side.
Pretty nice sailing, sails look great, need lots of downhaul to eliminate the classic throat/clew crease of a balanced lug. Didn't feel like i was pushing it, max speed 8.8 knots. The wind was all over the place, im not sure how well i sailed to windward. Mostly just beam reaching getting a feel.

Went back out on the water later with the first reef in, things felt pretty docile, just the beginning of whitecaps on the lake.

Several observations of things common to proas:

Sails bow-down when sails are powered up. Shifting weight helps, so my skipper's seat is always aft, moving gear (my trolling motor battery) made the biggest difference in trim. I should have gone with horizontal rudder hangers. Bow down plows.

Weather helm. I sailed all day with masts vertical over the canoe, and raked well forward toward whichever bow. My endless running bow-stay works well. Raking the mast hard toward the bow helped the weather helm noticeably. I did not try slacking the windward stays to cant the rig out to leeward, but that apparently that helps going to windward and the helm. Today the windward stays were fixed but it will be easy to make them adjustable to slack the rig out to leeward.

When shunting and speed is 0, the canoe really wants to sit beam to wind. Easing the sheets and dropping the rudders, the canoe is really stable. Apparently when back-winded proas can be frustratingly stable beam-on too. I didn't get backwinded today.

I was also just screwing around and did a bunch of shallow water capsize practice. The spars all float and the masts did stay on the surface. I'm sure with wind and waves it would turtle though. At 160lbs, I'm barely enough to right it from capsized. Lifting the masts a bit brought it under the angle of vanishing stability and it was a gentle enough as the canoe rolled up and the ama hit the water. Found out my big hatch leaks.

 

Well done! It looks good. Write another report after you have done a few more sails/ironed out the teething troubles and we can discuss any potential changes.

 

B Cowan, might have missed it, but was weight given?

Minimum area for a tack?

Pragmatic ?

Nic-a-bateau!

 

Bob Bill - thanks. My ama weighs 64lbs, the canoe weighs 165lbs, I havent weighed the sail rig and spars. Spars are 6061 aluminum, hollow and buoyant.

Im not sure what minimum area for a shunt is, I guess pretty small. Switching bows and changing direction is a breeze though, no leaving the captains seat. I let the sheets fly, switch the bow stay tension to rake the masts toward the new bow, the rudders kinda auto-shunt due to the leeway of drifting at speed 0. Pulling in the new sheets hardens up the sails and I was off and running. Shunting is easy and quick, no manually dragging spars from old bow to new bow, no clammering around on a the pointy ends of the canoe. So yes, I think pretty pragmatic. I doubt I can short shunt up a narrow channel efficiently without another person pulling on strings with me.

 

B. Cowan, reason I wondered about weight was simple comparison, Shunt area is different...we have a harbor here which has L-shaped ingress/egress channel and the channel is only about 20 meters wide, so...wondered....