An offset mast canted about 8 or 9 degrees would only lose about 1% of drive but would have a downward component of 10% of that drive. This would be effectively increasing the displacement by about 100kg when really driving it. Not a big drama. Drive would decrease faster than with a vertical mast as boat heels which is an extra safety factor. When the mast hits the water, there should be somewhere around 0.5m X tonnes righting moment from the CoB and CoM to bring it back up Can't see any problems if the mast is strong enough and it is not falling over sideways down a steep breaking wave.
The weights are encouraging for setting up a cruising extended Harry 15m/10m ready to sail w/out crew or stores at 1200kg/ I calculated 144m2 and assume stronger beams,masts and rudders to handle the extra righting moment of longer term stores and equipment
I assume the round beams rather than rectangular are for simplicity of build and windage
--- In harryproa@yahoogrou
>
> G'day,
>
> I have just loaded a picture of the new Solitarry to the Photos
> section. Actually, it is more of a harry with a 15m lee hull. Build
> is set to start in July, with one, maybe 2 full time helpers. Launch
> in October, maybe. The rendering is not totally accurate as it is
> mostly for sponsor gathering.
>
> Anticipated weights (from a discussion at crew.org.nz)
>
> Following are some numbers from the weight spreadsheet for my boat.
> Apart from the windward hull, it has all been engineered so I am
> confident the component weights are correct. Dave/Squid (potential
> short handed sailor..ed) would only need half as much windward hull,
> and there is 20-30 kgs to be saved from having a tube mast instead of
> the telescoping wing mast rig. A canted tube mast would make the boat
> self righting.
>
> Dave may also want to build the hulls from carbon as the small amounts
> required are not that big a cost. I have used glass as the Classe 50
> (French 15m multihull organisation, Crepes Wahou and co) requires it
> and they asked me to enter a harry in next years Route de Rhum (solo
> France to Guadeloupe) as they want to maximise their publicity. Bit
> full on for me, so I have got an ex mini 650 sailor to charter the
> boat, with a smaller windward hull.
>
> Lee hull:
> Surface area hull, deck and bulkheads, overlaps and tabbing 40 sq m
> Base laminate weight, 3.5 kgs/sq m
> Additional stiffening and local beefing up for mast bearings 30 kgs
> Paint and bog 10
>
> Lee hull weight: 180 kgs
>
> Windward hull:
> Surface area incl deck, bulkheads, overlaps and tabbing 54 sq m
> (Dave's is 25 sq m)
> Laminate weight 3.5 kgs/sqm
> Paint and bog 11
>
> ww hull weight: 200 kgs
>
> Beams 7.5m x 200mm dia tubes, including reinforcing at the hulls 18
> kgs each = 36 kgs
>
> Rudders, rudder mounts, tillers and extensions: 20 kgs each = 40 kgs
>
> Mast and boom: ~80 kgs (non telescoping one will be 20-30 less)
>
> Sail, tramp, rigging, cleats and blocks: ~45 kgs
>
> Ready to sail: 581 kgs
>
> Safety gear for solo Transpac which I would like to do next year: 180
> kgs Includes spares and nav equipment, not sure how it relates to the
> requirements for Cat 1 or Cat 3 in NZ, but seems close to what Mr Wolf
> has on his boat, so probably close
>
> Ready to race, ex crew, food and water: 761 kgs
>
> The list does not include:
> Daggerboards, cases and the hull strengthening these require.
> Harryproas have oversize, liftable rudders, mounted on the beams. They
> kick up without damage in a grounding or collision, are much easier to
> clean plastic bags and weed off and can be partially or fully lifted
> to balance the helm or reduce wetted surface.
>
> Shrouds, stays, forebeams, chainplates, rigging screws, traveller,
> winches, jammers, spreaders, dolphin or seagull strikers, jib tracks,
> turning blocks, and all the reinforcing and fasteners these items
> require.
>
> Jibs, screechers, spinnakers and their sheets and halyards. The rig is
> a single 50 sqm mainsail on an 18m tall x 600 chord unstayed wing mast
> which telescopes down to 10m. The boom is self vanging and the
> controls (halyards, sheet and downhauls) are 3 or 4:1 blocks and
> tackles.
>
> Much bog: The boat is built almost entirely from full length fully or
> partially glassed flat panels. These are bagged on a table and bent to
> shape in simple moulds so the surface is fair and ready for paint. All
> joins have radiuses and/or rebates for the joining glass. Little or no
> bog and fairing is required. This is a simplification of Derek
> Kelsall's KSS technique, made possible because there is no rocker in
> the hulls. We built a 15m hull and decks using KSS last year. Bit of a
> cock up with the bending and extra glassing so it weighs 200 kgs.
> Based on the time this hull took and the refinements to the build
> system, I am pretty confident my boat will be built in about 500
> hours.
>
> Pulpit (there is no need to go outside the beams), bunk boards and
> floors (integral with the structure) and wind instruments (with one
> sail you are either overpowered or not).
>
> regards,
>
> Rob
>
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