Marc Lombard designed lifting keel

[Ric]

Renowned French naval architect has recently developed a rather interesting swing keel which has been put into production on the RM1070 and Jeanneau 349. There is a nice moving illustration on the RM website here:

http://www.rm-yachts.com/rm-1070
(scroll to bottom of page).

Unlike most other swing keels, it does not retract into the hull (thereby taking up interior space), nor does it retract into a keelbox under the boat (thereby creating hydrodynamic inefficiencies). It looks like it is more intended to act as a long-keel when it is up, and an extremely deep fin keel when down, thus being oriented more towards sailors who want variable underwater geometry rather a boat that can be easily grounded (it needs legs to stay upright if grounded).

Has anybody had a chance to inspect this design closely at a boat show? Is all the ballast carried in the moving part? If so it must require a fairly hefty hydraulic ram to lift it. Is the keel made of cast iron? If so, is such a long and relatively thin piece not susceptible to cracking? How is the general engineering that must be required to spread the load to the hull? It would be interesting to know how these boats handle with the keel up when sailing downwind or on a broad reach.

 

[Seajet]

Ric,

I suspect she will handle very hard mouthed with the keel up; the snag with swing keels is wear at the pivot pin, which on some designs happens surprisingly quickly - if the boat is jiggling about even slightly on a berth or mooring for instance.

So design & construction of the pin, especially access to maintain / replace it, would be of primary interest to me if considering the boat.

It may well use a hydraulic ram on the top of the keel, but one doesn't need huge power; in the old days there could well have been a wire from the lower aft corner of the keel to a drum winch near the cockpit, maybe not so neat ( and good at catching weed ) but imparting a lot less stress on the boat and less likely to pack up !

As for drying out, I'd want to see the hull above the lifted keel area, it would need some sort of strengthening / protection from the keel trailing edge which is presumably quite sharp.

 

[Buck Turgidson]

Pogo 30 has the same thing.

 

[TimBennet]

Pogo 30 has the same thing.

So did the First Class 8 years ago.

 

[rwoofer]

So did the First Class 8 years ago.

And the first 210, 211, 21.7 and whatever it is now, thereby making the most popular swing keel design there is.

 

[Seajet]

More of them than Cornish Shrimpers ? Admittedly a plate as much as a keel.

 

[TSB240]

And the first 210, 211, 21.7 and whatever it is now, thereby making the most popular swing keel design there is.

+1

"Born in 1992, and named the First 210, this Finot-Conq plan took inspiration from the trends of the times to develop – First 211 in 1998, First 21.7 in 2004 and 21.7 Yacht in 2007 – and accomplish an outstanding career that could bring it into the pages of the Guinness Book of Records.

Nearly 3,000 boats now sail the seas

I dont think the output from Rock gets anywhere near these numbers with a single design!

A well proven keel design.