Downloadable Sailboat Plans by George Whisstock

New!! CNC Cutting Files for Design 077 Now Available Special Price

Also Special Advance Pricing on Design 160

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The George Blog – 10 Most Recent Topics

10 Most Recent Topics
Design 055 Stability Test posted in Design
Design 077 CNC Files posted in Design
Design 160 Weight Estimate posted in Design
Design 160 posted in Design
160 Progress posted in Design
Boat Kits by Truecraft posted in News
More Design 155 posted in Design
Design No. 155 – 14'9' (4.500m) Half-Deck Day Boat posted in Design
Happy New Year! posted in The Odd Word
New EasyBuild Range posted in Design

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Design 055 Stability Test

Last year one of our Design 055 owners, based in Brittany, France, wrote to say that he had experienced a swamping at sea that he wasn't able to recover from without help.

Now he was sailing the boat somewhat outside the original design brief – but that is how it is – 055 is a very robust and capable open sail boat. She didn't sink, but she was flooded to an extent that he couldn't bail her out because the seas were too heavy.

Design 055

So he proposed to seal off the areas under the foredeck and under the aft deck. Also seal off the areas under the floorboards and make the centrecase much more watertight at the top. We also decided to add 100 kg of permanent internal ballast.

We calculated that this would make the boat much more difficult to swamp, and even under those conditions, it would be possible to bail her out. This is due partly to the extra ballast, so she is more stable to begin with. But principally because when a very large sea lands in the boat, there is less boat for it to fill and more buoyancy to support the water flooding in. So she will float higher and be easier to bail out. And, importantly, the free surface effect of the flood water will be much less.

Having carried out the work over the winter this year, the owner put it to an initial stability test. The first job is to haul the boat down to 90º. That was quite hard to do and took two people to do it. Then once down to 90º, get her if possible down to 110º, which also proved quite hard to to – see the second picture.

The moment the owner let go of the mast, she bobbed upright again very quickly, with about 15cm to 20cm of water in her – easily bailed.

So far, so good – she is impressively stable. The next test, when the weather warms up a little, is to emulate a swamping out at sea. I am very confident that she will pass this with flying colours too.

We are also incorporating the components for the watertight compartments into the new CNC cutting files for Design 055, which we are preparing at the moment (available in about a couple of weeks), so future 055's will have this modification as part of the standard plans.

I took this to heart in the design of the new EasyBuild 15' day-sailer (Design 155): we have built-in buoyancy under the foredeck and aft deck; and also under the side benches (on 055 there are buoyancy bags under the side benches).

So I'm thinking that the new EasyBuild Design 155 can be pressed beyond her design brief. What's next? - an ocean crossing …

As ever I am impressed and humbled by the workmanship and care that went into these modifications. So much great boatbuilding goes on almost unnoticed.

George

Date posted: Saturday, 27 Apr 2013 | Comments (0)

Design 077 CNC Files

We have just completed files to allow all the plywood parts for Design 077 to be CNC cut. And these are now available on the website here. The files are in DXF format.

The files include new ply sandwich-construction frames.

The picture on the left is an image of the file for Frame -2695 showing the three layers of the frame.

These are located correctly together by a short length of 8mm dowel rod pushed through pre-cut holes in the ply, making assembly of the frames very fast, easy and accurate.

The frames end up with a stepped bevel on the outside edges; the thickened epoxy bonding the skin on will easily fill the little steps, so no bevelling is required.

Also included are files for all the lapstrake planking and pretty much all other components, flat or curved, that are made from ply. As far as possible we have used 9mm ply, so that builders will get economy of material when the components are nested for cutting.

The files are suitable for either laser or router cutting. All components are arranged so they can be cut from standard 2440 x 1220 (8' x 4') sheets, which can be pre-epoxy coated and sanded if wished. The files can be emailed to a local CNC facility (they don't have to have done boat work before). PDF files of each DXF file are included so that both builder and CNC cutter knows what the parts should look like.

As ever, we are happy to discuss the files with a CNC cutting facility, should there be a problem. Our experience so far with CNC cutting in many different countries around the world, many of whom had not ever cut boat parts before, indicates that the process goes very smoothly and easily, with near-perfect results.

Date posted: Monday, 22 Apr 2013 | Comments (2)

Design 160 Weight Estimate

We are now reaching the stage of the design where I have to start to fill in the weight estimate.

I have to make an estimate of the weight of everything, large and small, and estimate their centres of gravity longitudinally, vertically and transversely. I have to say this gets a bit boring!

It's both interesting and sometimes a bit daunting how the weight builds up as each new item is added. Eventually it all has to work out somewhere pretty close to the original assumptions that were made when designing the hull shape. If it doesn't, or can't be tweaked to do so, then it's back to the drawing board to make changes to the hull shape and/or the arrangement of the structures.

We do have some tools in our armoury – the most effective of which is to move or alter the ballast keel in some way to bring the longitudinal centre of gravity in line with the longitudinal centre of buoyancy. These have to coincide for the vessel to trim level.

The shape of the keel also has a big effect on the vertical centre of gravity. We want this to be low enough to give the yacht good stability, but not so low as to produce a very quick sharp roll period – which is uncomfortable. But the planform of the keel has a big part to play in the sailing balance of the boat, in conjunction with the sail plan, so we can't just move it around willy-nilly – unfortunately!

Any heavy item – engine, batteries, tanks, anchor cable, and so on – is a candidate for adjustment to the centres of gravity. And we look very closely at the rig in particular because rig weights are high up and even little changes there have a large effect on the vertical centre of gravity and stability of the boat.

That's why designers (well this one anyway) get really mad at builders or owners who increase rig sizes unnecessarily!

Date posted: Friday, 29 Mar 2013 | Comments (0)

Design 160

What I am really getting to like about modeling this design is that I get to see what previously I could only see in my mind's eye.

Take this image for example of the chine piece passing through a frame: the stepped bevel on the frame edge shows up perfectly – just as I imagined it would be in practice!

We are building our virtual boat in almost exactly the same way procedurally as we would be the real thing.

Date posted: Friday, 15 Mar 2013 | Comments (0)

160 Progress

The new EasyBuild 7.315m (24'0") Design 160, Full Headroom Sloop is proceeding apace. In collaboration with a colleague in Turkey we also are modeling the entire design in 3-D.

One important aspect of this is that we are drawing the frame layers first, ready for CNC cutting, and then inserting them into the model. So we are, in effect, building our virtual boat, from the real full-size parts as drawn.

As well as ensuring everything fits properly, this will also allow us provide a variety of ‘walk-throughs’ and other 3-dimensional illustrations which are so helpful in understanding how a new, as yet un-built design works.

As can be seen from the illustration, we have modeled the skin of the vessel and fitted the first seven frames/bulkheads. Once we complete the transverse structures, the longitudinals will be fitted into place and then the interior furniture.

I am also making a new webpage so that the design process can be followed and discussed in some detail.

Date posted: Wednesday, 13 Mar 2013 | Comments (0)

Boat Kits by Truecraft

We are excited to announce that Boat Kits by Truecraft of Adelaide, South Australia are setting up to build and market our designs, specifically building them from pre-cut parts.

The first two boats they are building are are No. 077 (15'6" Pocket Cruiser) and then No. 074 (19' 2-Berth Sloop). The files for CNC cutting are already available for Design 074, and we are now in the process of developing them for No. 077.

Truecraft will build a boat for you or provide space in their workshops for you to build, offering professional assistance if needed.

Contact Graham at graham@internode.on.net for more information.

I am looking forward very much to working with Graham on this project.

Date posted: Tuesday, 26 Feb 2013 | Comments (0)

More Design 155

Almost always in the process of designing a new boat one hits a snag of one sort or another.

When I design I carry the concept somewhere in my head – I guess because basically I'm useless at sketching things out on paper.

And I also suppose the "snag" is a bit of the concept that I have chosen subconsciously to ignore.

With Design 155, it is the outboard well! I wanted right from the start to be able to have the outboard in a well inside the boat, rather than outboard on the transom. It has always been part of the concept. But somehow, for some reason, my mental picture of the boat didn't really include this.

It has taken me at least a week to figure out a reasonable scheme. Not a week of constant work of course, but a week of leaving the design and then coming back to it, time and time again. Until that was sorted, the rest of the design simply came to a halt.

The solution that I have arrived at looks, and is, quite simple. And I've done something similar lots of times before. So I truly don't know why it took so long or seemed such a barrier to overcome.

Now I know what I want to do I am really impatient to get it drawn. That is the other thing I find about a snag – once it is solved, actually getting it drawn and finished never seems to go fast enough!

Date posted: Sunday, 13 Jan 2013 | Comments (0)

Design No. 155 – 14'9' (4.500m) Half-Deck Day Boat

We have now completed the naval architecture for Design No. 155, the second of our new EasyBuild range of sailboats. Over the next few days we will be finishing off the study plans and general arrangement.

With an estimated build time of four to six weeks (160 to 240 hours), this design should prove an attractive proposition. As with the ever-popular Design 055, this new boat will provide a fast, robust sailboat for lake, estuary and river sailing and longer coasting trips in reasonable weather.

As with all the boats in the new EasyBuild range, she can be constructed largely from CNC cut parts, for speed, ease and accuracy. For those who prefer to cut out the parts themselves, there will be drawings to accompany the DXF files, giving dimensions of all the parts so they can be marked out and cut by hand.

Date posted: Wednesday, 02 Jan 2013 | Comments (0)

Happy New Year!

So the world didn't come to an end, which is good!

Here in the Northern Hemisphere, we are at the winter solstice and from now on the days will gradually start to lengthen into Spring and Summer.

But at the moment, here in England, the days are short and the nights are long and boatbuilding plans are probably on hold during the festive season!

I'm sure we all of us, the world over, hope for a peaceful and productive year ahead.

Season's Greetings to all Whisstock's members and my Best Wishes for a very Happy New Year.

George

Date posted: Sunday, 23 Dec 2012 | Comments (0)

New EasyBuild Range

Our exciting new EasyBuild range of sailboats is underway!

Easy and fast to build to a high standard, without exceptional skills, these designs are simply a smarter way to build a boat.

Because of the intense amount of work needed to produce these designs we are seeking crowdfunding through our Indiegogo Campaign:

The EasyBuild Project – Boats That Almost Build Themselves.

More details of the whole EasyBuild project can be found on our website here

Please support us if you can! There are great rewards. Together we can do it.

George

Date posted: Wednesday, 05 Dec 2012 | Comments (2)