Monday, 2 September 2013

Saturday, 25 May 2013

Fantastic day, TP03 transported up to the club and assembled for the first time. Went realy well only two issues. Had to move one fitting on the mast and the seating platform is very slippy, should get him on the water in a couple of weeks.
See for all the details.

Sunday, 19 May 2013

All ready 6 days to go
Less than one week to go for the transport to SDSC of TP03 - the shoulder is getting a lot better and hoping to transport TP03 - next week end, 25th May. There is a large pile of stuff in the garage which in my mind is a very beautiful boat, I may be unique in this opinion. 

I have now built a simple model  of my lug rig with adjustable CE, I am very impressed with this rig I think it may well have some real potential. It offers a very clean sail, low CE and steering. Only suitable for small proas like my minimal proa though. 
For discussion see

for some video see

Saturday, 18 May 2013

The minimal proa continues to be my favourite new design, just the bare bones of a proa offering quick simple sailing hopefully along the lines of an international canoe but much easier to sail.
For discussion see

While working on the minimal proa proa I briefly got diverted to the idea of a inflatable version but after working out the details it just became complex without any great advantage.
For discussion see

This is the Strangford Lough Cruiser, it is a combination of a Bank’s Dory, Caddo Lake Bateau and off course a proa.

The brief is for a singlehander or two up for a day sail or a single hander for ultralight camping. The overall length is 14ft, due to building limitations. That’s where the Dory mid ships section comes in. With a 260kg displacement the hull draft is 120mm and L:B 11:1 up the displacement to 360kg and draft 200mm, L:B 10:1. I would have liked a finer hull but the draft increased too much, the bows are sharp giving fine entry. The Bateau influence is twisting the sides of the flat bottom v mid section into vertical stem maximising length and L:B. This twist creates some good flair for reserve buoyancy and keeping the crew dry.

Back to the Dory mid ships section, the flat of the bottom is 200mm, the gunwale 500mm above and a beam of 800mm. This gives space inside for a temporary birth of ‘bivi’ camping, a simple ‘tent’ protecting against the elements.

The beams in the picture are 1600mm apart so some ‘accommodation’ would be under the beams and deck. The ‘birth’ is removable like a camp bed made of material under tension

For discussion with like minded proa people see

Sunday, 24 March 2013

Friday, 15 March 2013

Cad model of minimal proa, two different wave piercing bows, tortured ply near, glass on foam in the distance. Liking this as a development

Friday, 8 March 2013

Cutting a long story short as the family skied in the glorious Courchevel I sat for nearly a week nursing a broken collar bone. While they had fun I did the usual, pondered Proas. The above is a cruising proa and the earlier one is a minimal proa. The real upset is that last weekend I should have been launching the proa TP03 which was all ready to go but now delayed until the shoulder fixes.

Thursday, 7 March 2013

Minimal Proa
I have been working on my minimal proa while my shoulder heals which delayed the launch of TP03

Description, specification
Minimal Proa with balanced lug rig and moving leeboard to align CE with CLR. Single central AKA, nod to Skip Johnson's AC/DC and Bionic Broomstick.
This is a concept for a possible next build after testing my current proa TP03 and will help clarify tests and developments to be done with TP03. The other concept I am interested in is a slightly bigger design with more freeboard and a small central open concept. This will allow two crew and storage of camping gear. All other aspects and hence development tests for this concept as per here.

Main hull
•  LOA 12ft hull, (3.7m) beam and draft 240mm, depth of hull 360mm, freeboard 120mm
•  L/B 15.25
•  Target weight whole craft 50kg, tough target, but research and a few calculation have given me confidence
•  Main hull displacement 150 kg total hull buoyancy 250kg, little reserve but think about  Hobie 16, trimaran floats, swath, Tepuke etc
•  Deck section at bows, addition of foam and glass to create wave piercing bow. This should counter low freeboard and crew fixed in the middle
Outrigger AMA
•  Outrigger buoyancy 50kg allows for crew at 50% beam
•  LOA 2.6m (8.5ft) beam 160mm
•  L/B 16.25
Overall beam tbc approx 1.5 to 1.8m
•  ply, simple box
•  plywood and polyurethane foam bulkheads.
•  All hull panels 3mm Okoume
•  3mm egg box constructed 'box' based on International Canoe sliding seat.
•  Hydrodynamic box shape lifts AKA 250mm above deck, as a result underside of AKA  370mm above static waterline. This reinforced box also contains a deep 'bury' for the mast and links righting forces with heeling forces without loading the hull. Leeboard loads are relatively close. The only other load being the buoyancy which is obviously spread throughout the hull. This all helps to produce a light structure.

AKA to AMA connection
•  Two flexible beams allow movement of AMA relative to main hull
•  balanced lug,
•  unstayed mast,
•  area 8m sq
Steering and lateral resistance,
•  leeboard mounted on track moves fore and aft to steer by achieving CE / CLR balance

Why's  and downsides
•  Proa (Pacific)
•  Max performance for given materials, performance means many different things, in this case it is reasonable speed in a minimal package
•  Downside, control issues, additional complexity?
•  Minimal
•  Low freeboard, very light weight,
•  Less materials
•  Cost
•  Weight
•  Less room to build
•  Easy to transport, fastest way to get upwind is behind / on / in a car
•  Easy to handle on land
•  Downside low freeboard drag,
•  Downside low buoyancy limits use; single handed daysail
•  Lug rig
•  Good performance for simple set up and small spars
•  Lower hull stress
•  Less set up time
•  Low CE
•  Heeling
•  Pitching
•  Downside ultimate performance
•  Free standing mast
•  Lower stress
•  Stress all in one place
•  Less set up time
•  One central AKA, also the seat
•  Simple
•  Stress in one place as above
•  Away from bow so possibly less drag from wave action
•  Less set up time
•  One item two uses
•  Downside can't trim fore and aft
•  Downside limits to one user
•  Steering with moving leeboard
•  One foil only
•  Low drag
•  Downside unproven, test with 2b
•  Sharpie (box construction)
•  Very simple build
•  Flat plate, ply, construction
•  Max buoyancy for box size
•  Helps leeboard system
•  Bow sections promote lift
•  Latest AC, A Class appear to have flatter sections
•  Downside higher weight and wetted area for buoyancy