Mike:
We all have our "shameful secrets"......... Mine is a love for the yawl rig. That silly little sail sticking aft has many uses, far more than most people realize. One of them of course being as an air rudder to balance the boat. On a Bermuda rig, one has two or more sails up much of the time, and multiple combinations possible for balance. On a junk rig you have a single sail, which is part of the beauty of the junk....... simplicity. The mizzen on a yawl offers a balancing sail as it is so far aft. It can be used to steer a boat, even with the rudder lifted on many points of sail. Some yawlies actually use them to back the boat up. It is often used to fly a mizzen staysail.
Imagine the stares I'd get with a 30' cat, a mast in one hull, and a mizzen hanging aft on the other ;-)
I'm dubious about popping up after a knockdown........... How many large HPs have been knocked down? The weight being concentrated in the windward hull, a knockdown seems highly improbable. Does the leeward hull go completely under? That seems unlikely, they look to have lots of displacement. Presumably the occupied windward hull would have to be lifted beyond 90 deg, pivoting about the leeward hull. I'm sure it's possible, but it would take pretty extreme conditions, or pretty extreme stupidity. They might be knocked down the opposite way a lot more easily... though the wind should not be coming from that direction. I've seen incredible winds, and seen them do amazing things. I've seen 80 mph (not kts) every year here. I've seen really wild stuff under thunderheads, gusts over 100 mph many times. I stopped on the highway one day a number of years ago and let a tornado cross in front of me in a remote area.
In any case, multihull capsize is almost always in the heat of a race........ Pushing way too hard, you round a point and a sudden violent gust knocks you over before you can release the sheets, or when surfing down wind without some sort of drogue to keep you from burying your bows in the wave ahead. The very long hulls on the typical cruising HP make diagonal capsize unlikely I would think, and that is the usual capsize mode for multihulls.
Personally I would not go to sea for long passages without some sort of drogue strategy. Sea anchor would be a good thing to have aboard also...... The ability to just "park" could be of real value at times.
Structurally, I'm not especially worried about a mast in one or both hulls. The loads are fairly easy to calculate, and the location would be right next to the standard mast beam. This is something that many people have done, and is well documented.
H.W.
On 06/05/2018 10:39 AM, mcrawf@nuomo.com [harryproa] wrote:
We all have our "shameful secrets"......... Mine is a love for the yawl rig. That silly little sail sticking aft has many uses, far more than most people realize. One of them of course being as an air rudder to balance the boat. On a Bermuda rig, one has two or more sails up much of the time, and multiple combinations possible for balance. On a junk rig you have a single sail, which is part of the beauty of the junk....... simplicity. The mizzen on a yawl offers a balancing sail as it is so far aft. It can be used to steer a boat, even with the rudder lifted on many points of sail. Some yawlies actually use them to back the boat up. It is often used to fly a mizzen staysail.
Imagine the stares I'd get with a 30' cat, a mast in one hull, and a mizzen hanging aft on the other ;-)
I'm dubious about popping up after a knockdown........... How many large HPs have been knocked down? The weight being concentrated in the windward hull, a knockdown seems highly improbable. Does the leeward hull go completely under? That seems unlikely, they look to have lots of displacement. Presumably the occupied windward hull would have to be lifted beyond 90 deg, pivoting about the leeward hull. I'm sure it's possible, but it would take pretty extreme conditions, or pretty extreme stupidity. They might be knocked down the opposite way a lot more easily... though the wind should not be coming from that direction. I've seen incredible winds, and seen them do amazing things. I've seen 80 mph (not kts) every year here. I've seen really wild stuff under thunderheads, gusts over 100 mph many times. I stopped on the highway one day a number of years ago and let a tornado cross in front of me in a remote area.
In any case, multihull capsize is almost always in the heat of a race........ Pushing way too hard, you round a point and a sudden violent gust knocks you over before you can release the sheets, or when surfing down wind without some sort of drogue to keep you from burying your bows in the wave ahead. The very long hulls on the typical cruising HP make diagonal capsize unlikely I would think, and that is the usual capsize mode for multihulls.
Personally I would not go to sea for long passages without some sort of drogue strategy. Sea anchor would be a good thing to have aboard also...... The ability to just "park" could be of real value at times.
Structurally, I'm not especially worried about a mast in one or both hulls. The loads are fairly easy to calculate, and the location would be right next to the standard mast beam. This is something that many people have done, and is well documented.
H.W.
On 06/05/2018 10:39 AM, mcrawf@nuomo.com [harryproa] wrote:
StoneTool,
The Iriquois 30 with a biplane junk rig looks interesting. It's edging towards as close as you can get with a catamaran to the safety/simplicity of a schooner-rigged harryproa.
At one point I was smitten by the Radical Bay 800, but eventually gave it up because there was no way to give it true double bunks, or queens for that matter, without making asymmetric hulls. The same goes for Cat2fold. Great designs, but too much money to consider sleeping in a tube if you're sharing a bunk. And since I've been fixated on a trailerable/transportable boat, a bridge deck doesn't cut it.
Reasons I like the schooner harryproa (feel free to disagree -- I know you're set on a cat):
- Less sail blanketing on some reaches.
- Ability to easily steer/shunt with t he sails in any wind strength, even if both kick-up rudders have somehow been taken out of commission.
- Easier to launch into the surf on a beat of close reach if you've beached the boat for maintenance (hulls meet the waves at the same time, shunting is more reliable and safer than coming about if the wind is light or heavy).
- The potential, though no guarantee, of being able to pop back up from a knockdown.
Other than that, the unstayed biplane catamaran has many of the benefits of the harryproas.
One word of caution: those hulls were not designed for the sailing loads of unstayed rigs.
I understand junk rigs can be more lightly loaded than bermuda rigs, and that the boat has reinforcements, but it's still something to consult an engineer about. Those hulls are not very tall, and they we re not built to support the full loads of an unstayed mast. They even have small ports directly next to the mast, and an open area just aft.
You could reinforce everything with enough additional glass or carbon inside, provided you get the directions right, but that would be a lot of work to get it right on that particular hull design.
- Mike
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Posted by: StoneTool <owly@ttc-cmc.net>
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