Planing Catamaran!

Yes that would probably be ideal to adjust the angle during heel though as you say it adds an extra level of complication and weight, though maybe not as much weight as a beery BBQ Xmas week with the relatives may add.
It may not be immediately obvious what we did in both the large and small planing boats was to pre-angle the hulls so that when the windward hull was completely out of the water by about 30cm or so the leeward hull was dead flat on the water , so it was optimised to plane efficiently flying a hull. Obviously flying a hull further changes the angle . You can see in the earlier linked image in previous post frontquicksmall.jpg that the hulls are mounted at an angle to each other so the leeward hull will run flat but in that pic I'm flying the hull a bit high for optimum angle.

On the big cat we angled the dagger boards so they were canted inwards to get some hydrofoil lifting effect whilst the hull bottoms were canted outwards. On the follow up 17ft cat designs we'd still like to try one day we have simply added some V to the hulls with outer downturned strakes and optimise the hull angle cant for the most likely anticipated hull-flying height. The nose would be sharply Veed to slice into large swell and boat wakes etc . But basically Parlier has already tried the same approach with their small verification cat. I've seen photos of some other similar designs but with scant captioning in foreign sailing magazines many years ago. Tricky to follow up on. But as you say it shouldn't be too difficult and heavy to mount the hulls to the crossbeams with a pivot to make the angle adjustable and settable and even incorporate some manually pumped hydraulics should that be found to be desirable but for initial tests we simply tended to get away with varying angle wedges under the crossbeams. You don't need constantly variable hull angling to make a planing cat or planing step cat plane. It may make it optimal but optimal is different from viable and still exceptional. Hang-gliders may not be the most optimal flying devices ever created but they are certainly viable. For my RC hydrofoils and step cats I tried the anhedral principle or marconi rig whereby the twin masts leaned towards each other ( anhedral obviously working to destabilise an aircraft but stabilise a sailing craft. ) For a beach cat that would be counter to the fun of getting out on trapeze! Malcolm McIntyre built a cool Marconi rig catamaran in the 1930s including a version using what he termed "skimming dish" flat hulls by which I assume he meant planing hulls . The design includes a number of ideas championed in the 60s by Bernard Smith in his "40knot sailboat " book , particularly the "inclined planes" (hydrofoils) which are positioned to exactly balance the forces from the sails and autostabilise the boat. The same auto balancing anti-heeling hydrofoil to airfoil principles were used on sailrocket. Bernard Smith lived just long enough to get a phone call from Paul Larsen telling him that his ideas had been validated by a world record using sailrocket V1 in Dec 2008 at 47.36kts but died in 2010 before Paul smashed it out of the park with S.R. V2 in 2012 with 65+kts I'm sure Bernard heard about Lindsay Cunningham's Macquarie Innovation exceeding 50kts with its three short planing hulls and at least it aesthetically resembled his ideas but operating principles of weight stabilising were different. and neither record breakers used aerodynamic rudder steering

An article on McIntyre's "sailplane" showing familiarity with Crossbow, Smith's aerohyrofoil designs and sailrocket amongst others. https://navalmarinearchive.com/research/pdf_ym/yachting_1934_feb_sailplane_sm.pdf

 

It's nice to see someone doing something like this in 1934.

On the other hand, proas in the Pacific also had decent performance back then. They weren't exactly planning hulls, but they did have hydrodynamic lift in high winds.

Far too few experimental boats were built. On the other hand, that's understandable.

 

It's big inspiration .

 

Love the pacific ocean proa varieties. Early European sailors often in awe of how they would head out in winds that the europeans would stow or reef their sails. That reminds me of the Erub island model races. https://www.youtube.com/shorts/i1QbBaQySHo https://www.youtube.com/shorts/8a290hNzBRk I remember watching an ABC story on these probably in the 70s and the shallow boats were effectively planks like a kite board and appeared remarkably fast for their size , fully planing and skipping across the wavetops. There was a good old news story in the 90s too on port moresby sailing outrigger racing with teams of hefty lads on the outriggers keeping the things level, huge roostertails from the stern with soaking wet skippers in the stern with steer paddles enjoying the mahem.

 

So that's how the Sailrocket was born.
Damn, I always forget that larger or bigger models exist. Making things much cheaper then fail or win expensive full-scale.
Remember some picture of Malcolm Tennant's room. There were 8-foot floats.

 

Yeah Paul posted some vid of the first sailrocket and the footage intercuts with video of their RC test models. I have more footage of the early model testing but it exceeds this page's upload size limit.

 

Any ideas how to beat them ?

 

I didn't know Paul Larssen was on the crew that retraced the Ernest Schackleton rescue mission .
Respect.

 

Where can I find the rules of the sail boat speed record , are there any restrictions?

 

The french guys are on an interesting track and I've been following it closely. And some Australian groups have proposed craft suspended in the air with only the foil in the sea. The kite idea has been around for a long time and I'm sure anyone who as a kid and owned a Peter Powel Stunt kite thought about the huge pull it could generate and used it to pull their surfboard along... ahem .... and I remember in the 80s the Weymouth speed trials had a kite pulled foiler tornado from memory called Jacob's ladder... Ah here it is: Jacob's Ladder http://www.panduj.plus.com/jladder/jl.htm. A ladder arrangement means lots of airfoil wingtips = lots of energy wasting tip vortices . Kites aren't very aerodynamically efficient and rather high drag compared to a smooth rigid airfol and one thing I intended trying back in highschool inspired by Bernard Smith's suggestions was to test an RC model and have a high aspect ratio performance glider on a tether pulling a cat type craft from the leeward hull or a centre swivel with a Smith's anchoring foil counteracting the upward lift and use ailerons, elevator and rudder to maintain its aerial orientation but after trying to just hand hold the launch tether on an rc glider connected via a winch launch hook that I could quickly release and imagine controlling that at a bizarre angle that plus steer a boat at the same time it was obvious that would be more than my brain could handle operating enough joysticks for each axis to sail anywhere and just end up with a waterlogged glider and corroding RC gear, It would still mean having a long strong tether which itself would have a lot of aerodynamic drag. The floppy kite of the French guys looks easier to handle than a sailplane ever could be (unless it was fully autonomous and autocorrecting) .... but landing such a beast at the end of a run at a large scale ? Fun in theory but fraught practically. Is suspect a rigid airfoil like sailrocket's might always be more efficient and lower drag and without the drag of long tethers that would be more efficient. I suspect Paul's team have a few tricks up their sleeve should the French guys break the record. And of course you are into cavitation and supercavitating foil territory at record speeds . Even my 16ft Skiboat with a 140hp motor can't get close to the speed Sailrocket has done but can just match the French boat... Water gets brutally hard at that speed range! One thing I sketched a few times though for a recreational fast sailboat idea was damped suspension for any craft with multiple planing surfaces to take the shock out of rigs and make the ride seem more tolerable for a sailer without having to make the surfaces strongly vee'd. I know it would add weight but with a clever design that may be minimised. The David Taylor model basin Navy folks developed a Dynaplane concept which was a stepped boat with adjustable position rear planing section so the craft could maximise its most efficient planing lift configuration for different speed ranges.

 

I think SP80 need better sea conditions . Namibia ?
Most kite boats utilize eliptical kite . For normal boat use (not speed records ) probably diffrent shapes will be created . Jacobs Ladder is interesting.
140hp should make 150 km/h on flat water with ease .Hydro or cat hull.

 

Yes I think the SP80 crew made an announcement on Facebook that they may continue their tests and potential record runs from Walvis bay in Namibia. though last year they reached close to the record... 15kts to go as average to match. It's an excellent site and the country itself spectacular to visit but the I imagine French guys will have more infrastructure at home to fabricate and make modifications/repairs. Not that it's relevant but the seawater in namibia has a year round particulate yellowish olive hue to it which seems more opaque than most ocean water I've encountered. Walvis Bay supports a big fishing fleet and there is a seal colony at the end of the sandspit at Pelican point but the locals in 2012 told me the WhiteSharks have not discovered it yet so a popular activity is kayaking amongst the seals and kite boarding in the bay.
140hp. Yeah I have an old haines 1600S with OMC140. Excellent ride quality in rough water with steep deep V but maxes out about 90km/hr. Prop set up for skiing rather than max speed.