Foiling Trailer sailer

I also cut a hole for a dorado vent in the foam deck beside the forward dagger board case   The box is all made in core cell foam and 1.5 mm ply remnants of a failed moth build and subsequently use on a recumbent trike . I was really pleased with the laminate consolidation carbon on styrofoam.

the first photo shows the galley with the stanchion tube posted in the mid upper part of the photo 

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Ah Good question 

Short answer is  I like wood work and it is cheap 2-3 x less than core cell  or divinicell  and I do not need to build a mould.

Long answer  Until Julian B  turned light weight  composite  hull construction on its head with pet foam and  thin 380 gm  basalt + 200 gm glass skins

 Building in foam was expensive .I was also concerned re the IMOCA  core delamination issues particularly on landing from altitude .  I reviewed Dave Gerrs scantling recommendations , Lords  Nevins and Herroshoff  rules  as well as ABS and compared that to what I knew of the NZ 1/4,1/2,and 1 tonners  Dudley Dix 's 6.5 m and sport boats when they were built in wood .Plus my multihull experience .

I made a number of test samples of ply with 3 and 6 oz glass one or two sides as well as carbon but orientated the carbon at +/- 45 degrees.I then using a load cell tested  deformation  in bending at various loads. Like the kayak builder huge increase in stiffness with carbon  such that  6 mm with carbon both sides was 50 % stiffer than 9 mm  and that was stiffer than 12 mm.

Scantling rules would have suggested 15 mm skin  Plus 300 gm glass  minimum 

Composites Canada had a sale on carbon at $ 15 per lineal  yd 1500 mm 100 gm biaxial and 300 at $ 20 /yd for rolls  plus Some 400 gm uni  $ 16 a lineal yd 1600 mm wide . So I thought I would substitute  300 gm biaxial for glass outside  and 100 inside with  selective  400 gm uni  on each side of Dagger board  plus all chainplates   and  across the inside of the cabin top . And 100 gm glass cloth  for fairing outside This would Give great  torsional stiffness and easily meet ABS code given the stringers ,frames + floors .  Plus the carbon looks cool inside !!! With hindsight I could have gone lighter  in ply  arranged the berth ,galley head  vertical to follow a  stringer  with little compromise in layout .Sorry longwinded .

 

pironiero

Member
496
119
I get that ply gets hella stiffer when used with glass\carbon on both sides, but what about weight? how much have yu gained approximately by using ply instead of foam? rough percentage will suffice 

drawings look very cool, you need to digitalize them

also why your inboard outboard is so far back? wouldn't it be better to make a well for it below the staircase?

 
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Tough comparison apples and oranges  ply vs foam   depends upon thickness of foam and thickness of laminate. Typically foam weighs 60-100 kgm /m3

ply wood is about 500 kg  Ie 4.5 kg/m2 at 9 mm or 3 kg at 6 mm but you usually use 3-4 x as thick foam   so  35to 60 %  of ply but  laminate is even with 89er spec is  2.2x heavier at 1100gm  [sum of both sides]cloth plus same in epoxy vs  500 gm . conventional  laminate thickness for glass is typically 1200-1400 gm cloth per side plus epoxy approx  this are still lighter than  scantling rules .

So my skin weighs about 4 kg for 6 mm and 5.5 kg for 9 mm  25 mm foam  80 kg/m3 is 2 kg  plus skins 2.2 kg   if Julian B or 4.8 kg if conventional  so 4.4 or 6.8 kg /m2   I probably do not really need all my stringers  but bulkheads and stringers weighed 90 kg  whole hull faired and primed with daggerboard case in weighed  252 kg.currently  as stands with interior in  deck on cockpit  finished   laminate on and faired mostly she weighs 520 kg .  Interior in foam ply is heavy too much area but it is unsinkable I hope .

Re outboard . I initially drew a well  for the ob but My friend Charles H who races Atomic out of Auckland convinced me that the noise and nuisance wasn't worth  it so I put a bracket on the boarding platform .However that is temporary because I intend to make a dagger board in the outboard box under the cockpit floor  with a electric 2-3 KW motor  and a 2 blade prop. Swing down to motor or regenerate power  swing up to sail. I have fair experience with electric mid drive  bike motors  they are quiet and will have a 40 amp hr 48 v battery pack. to power the electric ram actuators for the leeboards  maybe  Or I might use rope .

The space under the front of the cockpit is for a icebox .Beers you Know!! also stairs and slides out .

 
Weekend of vacuum bagging plywood skins 1.64 mm on to dagger board  . I also made up some filament wound supports for the stanchions at the forward end of the cockpit  . They will span from the main deck to the cantilever of the stanchion giving support and a footstep maybe  if I put a collar on the stanchion . Good use of pill bottles as 25 mm forms !!! Recycling eh 

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And the vacuum bag so noisey that I had to go and walk the dog . Well that is my excuse next will be fairing up the leading edge

0:8 %  of chord ie 4 mm . So templates out of steel . Once fair carbon biaxial over the outside to minimize twist.number of layers should be 2 or 3 depending upon achieved thickness vacuumed on . 
I discovered when making moth foils how important torsional rigidity is otherwise you have a bow rudder you can not control .I expect to place the centre of mass of the bulb slightly ahead of the centre of the daggerboard spar so that heel reduces the AoA of the bottom of the board. I don’t want a Fokker monoplane twisting the wing off.

really this is a much bigger for the leeboards due to the smaller crosssectional area.. They are next but at least they don’t have to fit in a case . 

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Sorry a bit distracted with work and upcoming trip to the gulf islands as a scouting expedition in may . Also still waiting for more epoxy.

working on dagger board cam out nice and straight. Measured up at 63 mm thick so I should have 5 mm to play with for carbon +/-45 skins  2 and 3 layers of 100 gm because I have it and am nearly out of 300 gm .

still have the leading edge to fair and template  tomorrow  prior to carbon and vacuum 

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Also cut out a section of snow leopards old tortured ply and carbon wing mast as a trial for the boom

measured front and back halves each with the shear web . Surprisingly the aft section was lighter at 800 gm for  500 mm so about 5.6 kg for the bare boom  with more than adequate section moment and carbon uni .saves a bit of work .

I glassed up the stanchion supports that I filament wound the edges of around pill bottle formers .Filament winding with either glass ,basalt or carbon is a really neat way to lash a fitting on to a base structure . Great for goosenecks  very Polynesian but a bit messy using filament single strand or chopped lengths then wound around with flagging tape or cramped or vacuumed bagged. But flagging tape is really quick and easy for cylindrical structure like moth wing struts or tubular gantries . All pas-a now with solid wings gantries and no struts .

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Vacuum bagged the  lee board verticals and rudder verticals this weekend  11 layers of 400 gm uni  per side on lee boards 9 on the rudders at about .9 bar  or 13 lbs per square inch  fairly well consolidated . Still template scraping the leading edge of the dagger board . I presume everyone is using the airfoil database and print capacity for generating foil sections 

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IanA.

Anarchist
801
522
Amsterdam
And the vacuum bag so noisey that I had to go and walk the dog . Well that is my excuse next will be fairing up the leading edge

0:8 %  of chord ie 4 mm . So templates out of steel . Once fair carbon biaxial over the outside to minimize twist.number of layers should be 2 or 3 depending upon achieved thickness vacuumed on . 
I discovered when making moth foils how important torsional rigidity is otherwise you have a bow rudder you can not control .I expect to place the centre of mass of the bulb slightly ahead of the centre of the daggerboard spar so that heel reduces the AoA of the bottom of the board. I don’t want a Fokker monoplane twisting the wing off.

really this is a much bigger for the leeboards due to the smaller crosssectional area.. They are next but at least they don’t have to fit in a case . 

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Looks great but just curious why you want less AoA at heel. Even on non foilers, there a component of lift you can generate balanced against your hull shape(or in your case, the leeward foil) at certain heel angles and speeds. Seems like most new fixed keel boats over here have been pushing the physical limits of intentionally twisting the other way and hanging their bulbs further back to induce this.  

 

Sidecar

…………………………
3,115
1,487
Tasmania
I get that ply gets hella stiffer when used with glass\carbon on both sides, but what about weight? how much have yu gained approximately by using ply instead of foam? rough percentage will suffice
There are other options, even stronger/stiffer, with a much thicker structural core for the same weight as ply and can be used unidirectionally, in any direction to suit:

https://paulowniatimber.com.au/marine.php

A renewable minimally processed product, also grown and available in USA and many other places. I have also used it for foils and rudders, all with with suitable sheathing. My 9.5 metre boat, home built, ~ 970 kg as per photo, made from carvel planked 190x12 mm paulownia, in some places cross planked, just like they did in the old days:

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