Search found 21 matches

by Robert Biegler
Sun Jun 04, 2017 9:42 am
Forum: Hydrofoils
Topic: Sonic tubes
Replies: 0
Views: 179

Sonic tubes

The designer of the Rave V foiling trimaran says that sonic tubes at the junction of V-foils reduce cavitation. See https://www.youtube.com/watch?t=228&v=JD5-shtZalY from 12:30. Does anyone know how these work? When I search for "sonic lifting tube," I only get sites associated with th...
by Robert Biegler
Fri May 12, 2017 11:54 pm
Forum: Technical Papers for review and comment
Topic: The WindFly Rig - Fast and stable kite boats - no heel, no leeway
Replies: 6
Views: 647

Re: The WindFly Rig - Fast and stable kite boats - no heel, no leeway

I have a read a bit more. Your WindFly rig is the most interesting boat-related idea I have seen in a long time. It is original, innovative, small and simple enough that it shouldn't be horrendously expensive, and could be applied to an enormous number of boats: everything that is driven by an outbo...
by Robert Biegler
Sat May 06, 2017 10:29 pm
Forum: Technical Papers for review and comment
Topic: The WindFly Rig - Fast and stable kite boats - no heel, no leeway
Replies: 6
Views: 647

Re: The WindFly Rig - Fast and stable kite boats - no heel, no leeway

For a few seconds, I thought this was like Ingo Voegler's setup (https://www.youtube.com/watch?v=ruBQ1CM_VUA), but once I read a bit more, I found that you are trying to achieve a whole lot more. I really want to know how it works out, so please do write that article, and make a few videos. I'd offe...
by Robert Biegler
Wed Apr 12, 2017 6:04 pm
Forum: Boats
Topic: MicroTransat
Replies: 12
Views: 1603

Re: MicroTransat

If the sailing airship is one of the options you will consider, email me.
by Robert Biegler
Sun Mar 26, 2017 9:31 pm
Forum: Technical Papers for review and comment
Topic: Howard Fund
Replies: 20
Views: 1683

Re: Howard Fund

For sure a wishbone could surely do the work too! But... - Some are not so effective for fine tuning the sails. Because you can't separate outhaul from leach tension? I think that could be done if you have a vang to regulate the vertical position of the end of the boom, and you attach the clew to a...
by Robert Biegler
Wed Mar 22, 2017 9:01 pm
Forum: Members Sales and Wants
Topic: C-class Emma Hamilton for sale on EBay
Replies: 1
Views: 387

C-class Emma Hamilton for sale on EBay

It's not me who is selling, but it seems AYRS members in the UK might be interested in buying a C-class cat: http://www.ebay.co.uk/itm/C-CLASS-CATAM ... Sw32lYwmv6
by Robert Biegler
Wed Mar 22, 2017 8:57 pm
Forum: Technical Papers for review and comment
Topic: Howard Fund
Replies: 20
Views: 1683

Re: Howard Fund

Actually, the rig is completed too; I'm now working on booms that are also quiet unusual. That was going to be my next question. I noticed the model has conventional booms and no apparent control over twist. There doesn't seem enough leverage for a vang, and a traveller might have problems with mas...
by Robert Biegler
Tue Mar 14, 2017 7:48 pm
Forum: Technical Papers for review and comment
Topic: Howard Fund
Replies: 20
Views: 1683

Re: Howard Fund

I'm the kind of helsman who like to sail with a long stick up to my shoulder and between two fingers! You can not do that with twin rudders. Me, too, but back when I sailed a Hobie 14, that's how I had it set up, and with much of the lateral resistance being provided by the rudders, they saw some l...
by Robert Biegler
Sun Mar 12, 2017 7:23 pm
Forum: Technical Papers for review and comment
Topic: Howard Fund
Replies: 20
Views: 1683

Re: Howard Fund

Have you decided how to attach the masts to the circular track? I suppose that connection must cope with compression as well as upwards pull. And I think sail forces will always push the whole kaboodle to lee, so you must actively control the angle of the mast assembly to the wind? Rotation of the m...
by Robert Biegler
Thu Mar 09, 2017 7:42 pm
Forum: Hulls & Keels
Topic: Transonic hull
Replies: 6
Views: 1162

Re: Transonic hull

I first came across the transonic hull on the proa forum, where someone suggested that two of them joined end-to-end might make a good proa hull. I found that so counterintuitive that I looked it up, and a few days later found your report in the latest Catalyst. And today, I came across a crowdfundi...
by Robert Biegler
Thu Mar 09, 2017 7:38 pm
Forum: Technical Papers for review and comment
Topic: Howard Fund
Replies: 20
Views: 1683

Re: Howard Fund

One of Dashew's books has a picture of an Open 60 (or possibly a predecessor to that design rule) with such a rudder. I think it was called a tilting rudder there. I also saw it on Mudskipper, a steel cruising boat from Australia that came to Trondheim. There are pictures in one of the Junk rig Asso...
by Robert Biegler
Thu Feb 23, 2017 9:22 pm
Forum: Technical Papers for review and comment
Topic: Proposal: Sail Performance Analysis Rig (SPAR)
Replies: 7
Views: 771

Re: Proposal: Sail Performance Analysis Rig (SPAR)

Your diagram describes something not physically possible. You have negative drag. If that existed, we could build a perpetuum mobile. Imagine your sail were mounted on a wind turbine hub, in a dead calm. Assume that the vertical line that shows wind direction is the plane of rotation. Push the rig w...
by Robert Biegler
Mon Feb 20, 2017 5:46 pm
Forum: Technical Papers for review and comment
Topic: Proposal: Sail Performance Analysis Rig (SPAR)
Replies: 7
Views: 771

Re: Proposal: Sail Performance Analysis Rig (SPAR)

As an amateur, I'm pretty much solely interested in comparing competing equivalent sail forms in terms of forward thrust generated by the sail, relative to the wind across a range of sheeting angles, and the cost in heeling force. Both of these seem to be indicated by mast heel deflection in the SP...
by Robert Biegler
Sat Feb 18, 2017 4:26 pm
Forum: Boats
Topic: MicroTransat
Replies: 12
Views: 1603

Re: MicroTransat

It would increase displacement, though. It doesn't matter to displacement whether you carry the weight in the form of water or something else. If you start thinking of a hull, then mentally add a water-filled keel, you don't need to make other alterations to the hull, and that can give the impressio...
by Robert Biegler
Thu Feb 16, 2017 7:47 pm
Forum: Boats
Topic: MicroTransat
Replies: 12
Views: 1603

Re: MicroTransat

I wondered if a trimaran with a water filled ballast keel to allow recovery from knockdown Why water ballast? For a given weight, lead would give you a lower centre of gravity. The advantage of water ballast is the ability to dump it or take in more. That seems an unnecessary complication while und...
by Robert Biegler
Thu Feb 16, 2017 7:40 pm
Forum: Technical Papers for review and comment
Topic: Proposal: Sail Performance Analysis Rig (SPAR)
Replies: 7
Views: 771

Re: Proposal: Sail Performance Analysis Rig (SPAR)

I can see how knowing the direction of the wind and of the deflection at the base gives you the lift to drag ratio, but only if any vertical sheeting forces are contained within the rig, through a really strong vang, or a wishbone boom. Sheeting as shown in the picture would pull the rig back and mi...
by Robert Biegler
Sat Feb 04, 2017 5:34 pm
Forum: Technical Papers for review and comment
Topic: Mark Hillman's proa
Replies: 0
Views: 340

Mark Hillman's proa

If the top bends, it eases gust loads The sheeting is not specified in the Catalyst article. If it is as with a lug sail, single sheet and control twist partly by tension on the tack line and partly by how much sail is before the mast, then I can see that happening. If the plan is to use junk.rig-s...
by Robert Biegler
Sun Jan 29, 2017 6:20 pm
Forum: Gossip & other snippets
Topic: Autonomous ships
Replies: 2
Views: 801

Re: Autonomous ships

It won't be long before we all need to have AIS receivers I have read reports of Large cargo ships being built with a view to no crew, trials initially with monitoring by a crew on board and later with just computer observation from shorebased offices; presumably after that, let loose on their own ...
by Robert Biegler
Sat Jan 28, 2017 6:05 pm
Forum: Hulls & Keels
Topic: Transonic hull
Replies: 6
Views: 1162

Re: Transonic hull

Caveat - I've never seen one of these hulls in action ... The pictures in the paper are reasonably consistent with the claim, but video would be nice. I suspect that if you work out the curve of cross-sectional areas, and built another hull with the same curve it would have the same wave making cha...
by Robert Biegler
Wed Jan 25, 2017 8:54 pm
Forum: Hulls & Keels
Topic: Transonic hull
Replies: 6
Views: 1162

Transonic hull

At http://www.din.unina.it/HSMV%202011%20Proceedings/html/Papers/28.pdf there is a description of a hull shape intended not to make waves. One of the postulates which led to the development of the described hull shape, a tetrahedron with rounded edges is: If such new shape avoids curvature in its wa...
by Robert Biegler
Wed Jan 25, 2017 8:26 pm
Forum: Boats
Topic: MicroTransat
Replies: 12
Views: 1603

Re: MicroTransat

My purpose in approaching your society is to seek your opinion as to whether you consider the idea of building a vessel (max length 4m) propelled by wind power only and to send it on a mission to traverse the Atlantic completely autonomously is feasible. I know it’s feasible for a moderately-sized ...

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