High Performance Outrigger Pt. II

It is a given that when the float is leeward on starboard tack and to windward on port, that the boat behaves very differently on each tack. With the float to leeward it is not practical to attempt to fly the float in strong winds as the smallest mistake by crew or skipper leads to an immediate capsize to windward. Therefore the trim for safety becomes such that the float is allowed to press well into the water; which is not ideal for a very low buoyancy float, being less than half the sailing displacement of boat and crew. The main hull is long and narrow and designed to plane with it's flattish bottom but is being held back considerably by a float that is well on its way to being fully immersed, and creating considerable drag.

On the opposite tack, one encounters a new set of circumstances, and this in itself creates a major problem, as you need to remember that suddenly your boat has completely new handling characteristics. This I knew from the outset even before construction, and it sounded to me that it would be challenging and also fun. This was true in light and moderate wind, but when sailing in overpowering conditions such dramatic differences are the last thing the crew need when really only desiring to stay upright.

When sailing with the float to windward, in stronger winds, the float is flying well clear all the time which means that crew balance is critical as the main hull is the only thing in the water. At 40 cm. wide or a little over one foot, this is a lot like walking on a tight rope as the crew is hiked out on the trampoline wings. The boat feels as though it could capsize readily to leeward or windward as it powers on as if it has a mind of it's own. In fact it can only capsize to leeward, but it will topple the crew out of position if suddenly the windward float comes down into the water unexpectedly.

My inescapable conclusion is that such an asymmetric configuration is fundamentally flawed and serves only to frighten the crew into not wanting to go sailing except in light conditions. Therefore my choices are now to either abandon the design or to try to solve the design problem as best as is practical without discarding everything that I have already built. The only solution that I can see is to convert to a trimaran, which overcomes several deficiencies in the original design. It would achieve the following improvements.

• Identical handling on both port and starboard tacks.
• A more stable wider platform that would be less intimidating for the crew in strong winds.
• The ability to hike out further, onto the windward float, and develop greater righting moment, and simultaneously be sailing a boat that is much less likely to capsize.
• The ability to carry more sail as currently we are reaching the limit of righting stability long before reaching the limit of longitudinal stability. That is we have not experienced yet any tendency for the hulls to nosedive.

Whether the floats should be increased in buoyancy to able to float the entire displacement of boat and crew while essential in a larger craft is optional in an off the beach trimaran where crew weight is the main factor to balance the power of the sails. My current thinking is that large highly buoyant floats would create a situation akin to a super wide catamaran which is not at all challenging to sail, so I intend to use the current float as a male mold to create two new super light weight floats in carbon fibre.

Comments

• Hello—I have had my 14 foot shunting proa out in ~20 knot winds.  I found it hairy at first until I calmed down and noticed that my small ama, which has about 50 to 75 pounds of bouyancy, was a good safety feature.  The ama was submerged frequently, and when water floods around the foam blocks under its deck, the ama weighs about 75 pounds.  If I sail from the vaka, sitting on an aka-bench, the ama is buoyant enough.  As waves envelope it, as happens in choppy harbor water in ~20 knots wind, the ama is protected from popping up: the proa never threatened to capsize to leeward, and as long I stay on the aka bench, capsize to windward not a threat either. The ama sinks slowly enough so that an accidental leaning too far to windward is not an immediate disaster.  So an ama closer to the native’s neutral-buoyant long amas is not a bad idea to test out.  However, my proa is small, 14 feet by 6.5 total beam, so I don’t know how this behavior would scale up. The worst moments in this wind was shunting the crabclaw sail; the heavy boom to lee in a pitching water was a little scary as the boat started rolling.  --Wade Tarzia

  Posted by  on  11/02  at  07:42 AM

• I want to comment on the editors note (of Sam Frosh’s contribution) which states that the tacking proa is not a sensible design when used in higher winds.

  I do sail a completely different design of a tacking proa it is a 14-footer for two persons.
  Of course it is old and not made for the speed-thrilled, but therefore I had a somewhat different experience in higher winds, presumably because of smaller sail area. I have sailed a lot in 30 to 35 knots, wave height was about 2-3 feet. It was not scary, no risk of capsize, albeit sometimes wet. But I had reefed the sail a lot, a simple kind of roller furling-reef
  of the sail around the mast.
  From my experience I cannot conform that the tacking proa design itself is not a sensible design when used in higher winds, I had a safe and assured experience, so to me the tacking proa is a very stable craft in higher winds and choppy conditions.
  I am open to any ideas which 14-feet craft would be a better choice in such conditions, preferably also from owners experience.

  Of course, as for any craft, there are limiting factors in highest winds.
  As the float (ama) of my proa is rather buoyant,
  I think the windage of the trampoline (aka) will be an issue in winds way up above 35 knots, in example, if a wave throws the ama up in the air,probably even if the crew is hiking out on the ama.
  I should also mention that wind-chill and hypothermia can be a serious problem when sailing in these conditions on a small craft without a cabin.

  Maybe of interest, this small tacking Proa has a deep V-hull and a freestanding mast in front of the canoe (vaka) which hoists a boomless sail with a mast-sock. The sail has a curved
  leech and the mast-sock bends the mast backwards, similar to a windsurfer sail, so the luff of the sail is longer than the leech.
  A picture of the proa can be found at

  http://www.lucciorlandini.com/proa.swf

  So I do not want to compare this to the design of Sam Frosh, a completely different story,
  but the tacking proa itself I think is not unsafe.

  Best regards,
  Heinz

  Posted by  on  11/07  at  06:15 AM

• Thanks for the comment. That’s a nice little outrigger - love the way the ama stows neatly inside the main hull. Sam’s experience is only for his own craft, not for all outriggers, yet that is his opinion, and he’s entitled to it. I agree that tacking outriggers can be perfectly safe, but his craft was so highly strung it was difficult to sail in strong winds, which shouldn’t be taken as a criticism of the entire breed, just like you shouldn’t judge all monohulls by the sailing characteristics of just one class.

  Posted by  on  11/08  at  08:03 PM

• Just a comment on the two respondents to my article entitled “High Performance Outrigger Part 11”. Both Heinz and Wade Tarzia sail tacking proas that seem under powered for common wind strengths. In one case the aka is carrying water ballast in stronger winds, and in the other the craft is close to being a catamaran as the ama is very bouyant. This boat is sailed in wind strengths of up to 35 knots, apparently without needing to reef the sail, so probably should be set up for a higher power to weight ratio. My point is that a tacking outrigger needs to be a Pacific Proa on one tack and an Atlantic Proa on the other. As each design needs different characteristics of aka design and bouyancy it is not possible to have one craft that is optimised for both modes of sailing. The other main point is that my design was meant to challenge beach cats for speed so that power to weight needed to be as high as two crew could comfortably handle in moderate to strong winds, i.e around 20 knots. In lighter winds even a design that is ultimately flawed may sail and handle reasonably well.

  Posted by  on  11/20  at  09:18 PM

• Hydrovisions makes a high performance sail/paddle outrigger canoe that overcomes many of the limitations of a single outrigger by using a adjustable hydrofoil that lifts on one tack and pulls down on the other.
  There are more details at their site:
  http://www.hydrovisions.com

  Posted by Michael  on  12/06  at  06:59 PM

• Presently planning to upgrade my Klepper Aerius II folding kayak, which I use as a two-man tacking proa, to a more proper ditto, see URL, the A64, a brand new design by Chris Ostlind. It is optimized for paddling and sailing, with two full-size persons (me and my wife) and gear for about a week.

  It is not intended to be a speed demon, at least not when sailed with the yawl rig depicted. Chris have bigger rigs in mind for it, but then I am sure the unplannded dunking will come, too!

  Tord

  Posted by Tord S Eriksson  on  01/17  at  04:27 AM

• Oops!

  The URL seemed to have gone missing:

  http://foldingkayaks.org/gallery/Boeing-ized-outrigger/A64_Lug_bow_obl_w

  Tord

  Posted by Tord S Eriksson  on  01/17  at  04:31 AM

• I sail a larger version of Hydrovision’s Raptor called a Slatts 22. I modified it to get port/starboard seating instead of the in-cockpit style it was designed for.

  Even with the hydrofoil it definitely exhibits some of the differences Sam mentions about port tack versus starboard. As the windspeed increases, your alertness and mobility need to increase as well.

  I’m planning to test it this season without the hydrofoil and use bodyweight/position, (along with tiller/mainsheet of course).

  http://www.signaldesign.net/different22.html

  Charlie

  Posted by Charlie Magee  on  02/02  at  05:30 PM

• Since I posted the massage above Chris has published an article in the Duckworks about my coming tacking proa:

  http://www.duckworksmagazine.com/06/designs/a64/index.htm

  I will have a safety ama on the other side (not included in the pictures published at Duckworks), a design feature Gary Dierkin uses on his proas (usually detachable).

  Tord

  Posted by Tord S Eriksson  on  02/03  at  05:06 AM

• Sorry for the spelling errors: message, not massage, and Gary spells his last name Dierking!

  Tord

  Posted by  on  02/03  at  05:23 AM

• read that as a tacking proa?well theres the problem,the original design lets you depower the rig by adjusting the lean of the mast,also i dont think speed was a big concearn with original design,it just happens.if your proa has a fixed mast you have a narrow canoe with a sail,so it is a tender setup.Funny how to me the traditional proa idea works better than anything new.

  Posted by  on  11/05  at  10:25 AM