Small boats playing in strong wind ?

How radical do you want to be? You could set up a rig that does not generate heeling moment. Here are a few examples: Non-heeling rigs | Boat Design Net https://www.boatdesign.net/gallery/non-heeling-rigs.29540/ (I don't know why the site refuses to show this image, so I can only offer a link.)

The boat on the lower left meets your criteria of sitting down and remaining dry. I would not recommend the bidirectional rigid wing. If it is bidirectional as shown, it is difficult to fully depower, and if it is rigid, it needs to stay up. In fact, the boat shown was destroyed on its mooring not long after being completed because the wing was up.

If you want to be only mildly radicalish, the idea I want to test next on my sailing canoe should also meet your needs IF if works as intended. Imagine L-shaped foils like the Birdyfish dinghy's:

Instead of letting the foils stick out of the hull, attach them to the deck. Give the deck some slope, say 30 degree. The inner part of the foil would lie flat on the deck. Make a hinge with an axis parallel to the deck, but at about 45 degrees to the longitudinal axis (if the foils have no sweep forward or back, and you want them to fold to lie parallel to the longitudinal axis, then exactly 45 degrees). That lets you fold the foils up and back over the boat when you need them out of the way, but only if you have an unstayed mast or two stayed masts, because their path will go through where the shrouds of a single stayed mast would be. If you swing the foils by only a few degrees, the inner part pitches up and gives more lift. The outer part initially points out a little more, then start swinging in. So if the outer parts have a little toe-in at rest, then in light winds, you trim the foils so that the inner part has minimum drag, and the outer part provides lateral resistance. As you need more righting moment, you let the foils pitch up a little. Make a cockpit that has a windscreen and a sort of fighter canopy that you can either slide back when you want your head in the wind or that you can slide forward and clamp down when you need protection and waterproof integrity for buoyancy if inverted.

Tacks in the winds you want to deal with might be a bit more interesting than is desirable, because if you go backwards, those foils will not provide a lot of righting moment. If you have a sail that reefs or completely drops easily, perhaps a split junk, then you might be better off gybing.

For another alternative, Jon Howe presented an idea f0r a loop keel that was supposed to provide dynamic righting moment without moving parts. It got a largely sceptical reception here, but the test results he described seemed promising. Search for loop keel. Unfortunately, the links he gave to further information on how to design your own are now defunct.

 

That drawing was by John Welsford and one of those "around in 10" concepts. I guess it could be pulled out for more length and the topsides either side of the helm station reduced as much as required. The inly things with sails on that i know of that go out in winds like that are sailboards, but i can understand why an enclosed sailboat might be fun.

 

You have too long a list to describe any real physical boat and you top it off with the overarching purpose of making high energy survival conditions fun.
You already have two small boats that might be expanded in capability. My suggestion is to change the sail to a fully battened single sail that is flat and low enough drag to feather to near zero force. Make the tip buoyant and eliminate stays that would limit angle of attack.
If your hulls are not fast self draining they are wrong. My strong advice is lightweight and fast full recovery. "Self-righting" makes no sense in these conditions -you need a craft that will absolutely NOT sail away without you and not blow away either.
Making the boat for two is another non-starter. You might be crazy enough to endanger crew but no competent designer would tell you you can.

Windsurfers and kiteboards have the aero and lightweight to enjoy these conditions but they are flawed in that they put the forces through the body of the sailor. Only kites address the righting problem and the problem of losing wind in the troughs of waves where it's uphill in every direction. My direction would look like a surf kayak with kite management. Foils can be small because the speeds are high.

 

Hi Robert, interesting suggestions, but they look fragile for heavy weather, and would require a rescue craft if damaged since they would be difficult to manoeuvre if any part broke. Probably great on lakes without big waves, and would be fast there. Your foil idea on the outside looks like a good one, if it can take the stresses where they attach. Not sure about the hinge idea though, it could be the weak point. Good luck with your trials of it. The loop keel is new to me, and a bit novel, not so convenient for trailering and ramp launching though.

Hi Skyak, a surf kayak could be adapted. The sailing drones often have a kayak like hull shape. Most of my kayak experiences have been wet, and sitting in a confined space can be annoying after a while. It's heading back toward the hull shape of lifesavers' surf skis, with the anti dive canard at the front. With a longish weighted shallow keel underneath to avoid constant eskimo rolls and reduce side slip, a small kite, and a simple lateen, and foot pedal steering, it could be fun and fast in a blow. Car toppable or trailerable, beach launch even, sounds like a versatile compromise, (no cabin though, maybe a dry suit needed), and when everything breaks you can pull out a kayak paddle to drive and/or steer, and get home safely eventually. At least a surf kayak or surf ski has very little windage, so that's one problem greatly reduced, while making another, where to put my hot coffee and museli bars.

 

The maximum load from fluid flow depends only on flow velocity and maximum coefficient of lift. That maximum coefficient can be higher than the steady state maximum when angle of attack increases quickly, because flow may not detach immediately. Heavy weather will only increase those loads to the extent that you go faster.

The foils would be an important source of stability, and their loss would have similar consequences as loss of a ballast keel. Choose your safety factors accordingly.

Things might get unpleasantly exciting if you retrieve the foils to enter harbour in strong wind. Then again, you need a centre of gravity low enough for a good stability curve anyway, so this might not be a problem. I would consider putting the mast in a tabernacle, so I could quickly take it down. That would also help with trailering.

Structurally, it should be similar to a trimaran, and some of those use hinges with shorter axle length than I intend. Therefore I think a strong enough structure can be built without excess weight.

If you make the cross section of the loop rectangular instead of triangular, it should be possible to make a lifting loop keel.

Kiteboats that might interest you:



There is also a very ingenious scheme described in an issue of the AYRS journal Catalyst, but I won't have time to search for which issue it was for at least a week.

 

I think some clarity is needed. This is a "surf kayak" 20-Pound Matunuck Surf Kayak from Nick Schade: Build from a Kit or Plans! (clcboats.com)
It's like the love child of a kite board and a wooden shoe.
-no relation to "surf ski"
-hull is completely optimized for planing
-edges are sharpish curves for control. No canard, or any foils forward that could catch and trip the boat.
-This is the best hull form for handling in waves that are bigger than the boat.
-plenty wide for stability when stopped. Plenty of room for food and drink

Your application would have less emphasis on paddling but need to manage a kite. I would make one a little bigger with provisions for little daggerboards just forward of your hips for upwind. The seat could be more reclined and you could have a windshield that lifts and slides back from the deck to deflect spray over your head.

I think you need to give up the idea of lead ballast at the end of any keel because they do nothing significant until 20degrees of heel and need too much foil to get to depth. The deep foil will be trouble at even the speed of sliding down waves. I would give up on full enclosure until you have a well sorted craft. Until then you should focus on being able to reach everything you need to without exiting the boat (intentionally or otherwise). The conditions you specified are threatening even to recue craft, so dressing appropriately for a wait in the water can't be avoided.

 

Are you getting at a Jubilee or a shortened Soling with leeboards that act as foils, a stubby mast,,positive buoyancy and a perspex bulb to sit under?

 

I totally forgot that there is a video claiming to show what you want to do. I don't know whether the 50 knots is based on a measurement, and if so, whether the measurement was on site or at some weather station that might be rather more exposed. Still a fair bit of wind:

 

Beating 30 Knots

It is a difficult question, a high Freeboard for logical safety reasons plus a wide heeled sailboat Hull creates a large Windage

Windage on the one hand is Aero Drag and on the other hand is Aero Side Force which loads the centerboard and rudder blade creating Lift/Lateral_induced Drag.

 

True Wind Speed @ 10 m high (A3): 30 Knots

SailBoat LOA and LWL: 6 m
Freeboard: 1 m

Aero Lateral Force Sail and Hull (heeled Hull) (A18 --> D18): 1919 Newtons (!!!)

Aero Drag Hull (A20 --> D20): 426 Newtons (!!!)

A possible solution is to load Sea Water, in this example the small sailboat has loaded 170 liters (C19) but to go around a bay, this solution may be inconvenient as the ballast tanks have to be emptied and filled.

 

Screenshot 2023 06 20 10 25 12 55 — Postimages https://i.postimg.cc/13rj1g7m/Screenshot-2023-06-20-10-25-12-55.jpg

"American Express"
(1979 Mini Transat)

It carried about 260-280 liters of seawater on the windward side.

 

IMG20230620120023 — Postimages https://i.postimg.cc/Fs0TWqJS/IMG20230620120023.jpg

1 meter of Freeboard and 2.5 Beam with 15 degrees of heel becomes 1.4 (!) meters.

So a logical path as has been said in this thread is a narrow sailboat.

 

That's a beautiful wooden shoe Skyak. Imagine that with a long tail motor on the back. (See post above a bit) Yes there is some confusion, and crossovers with surf skis, wave skis, kayaks, and others. I did some different searches and got more confused. I wouldn't want to be kneeling for ages, prefer legs out straight, or sitting / reclining. Keel weight wouldn't be helpful, but maybe fixed foil shapes on a keel could be. Side mounted daggers could work, like lee board in a sturdy pocket. I do think a mast will be needed to be able to climb into the wind and make headway, and kites for following winds.

TTLF something smaller than those, narrower, probably lighter, but the perspex bubble cockpit could be good. So many different ideas, pro's and con's in these conditions, and there's more than one way to skin a cat.

Thanks for the vid Robert. He was going amazingly slow, because of being over powered and keeping tight to the wind to stay upright. Lucky the spinnaker was so small he could drag it in, while being a submarine. I didn't think an Illusion and similar micros would be happy in those conditions. Maybe with useful small storm sails and not heeling so much he would have done better.

Hi CarlosK2, thanks for your input. The windage is too much energy at the wrong angles when heeling, water ballast (in this application) only works on a wide beam, and that wide beam presents more windage at heel, it's a mini design spiral. Narrower seems to be a solution for less windage, or somehow staying very upright so only the gunnels and decks are windage, flat like a catamaran not flying a hull. There would be little time for manual pumping in windy conditions, and batteries and pumps are heavy, so water ballast is out, unless it is scooped up by something while travelling, and dumped with ease very quickly, meaning systems and weight and complexity.
Could you run some numbers on a cylindrical submarine type hull at half immersion ? Like 3 feet or 1m diameter, and 15 feet or 5m long, ballpark figures. Can't get much less beam than that.

A long sailing sea canoe with lee boards maybe ?
I'm running out of different ways to look at it.

 

Maybe with a fully enclosed cockpit cover like a Hurricane. This was fast down wind in flattish water, as in 10-15knts. It required major hiking to get back upwind in strong wind. I should never have sold it, and easily car toppable. A deep dagger board with a bulb could remove the need to hike.

 

Skaraborgcraft that's a very nice hull, I feel your seller's remorse. Something like that, about 20% smaller, sit in like a canoe, one mast with much tapered balanced lug, which roller reefs down to an 'effective' storm sail shape, a shallow weighted keel would help greatly. Going down wind stow the lug against the mast, to keep it simple, and deploy the kite, or an asymmetric.

I was thinking, militaries made gliders, and parachutes to sneak people into secure places by air, and mini submarines, and I'm sure the world's navies have tried assorted un powered craft to land people on shores in secret, no radar, no sonar, not much bodyheat, little noise. In a storm at night a small wind powered vehicle could arrive un noticed, filled with marines or seals or whoever. How many navy seals can you fit in an all black Optimist ? So where are these prototypes and crazy military ideas ? What would James Bond use ? Shaken not stirred, step off, undo the dry suit, and stroll about dressed for a royal ball. What would Dr Evil have ?
Some fanciful idea may be the answer to controlled use of a gale by a small vessel. Midget sub with sails used as a motor sailer ?