Here is the draft of Page One

Boatbuilding (in plywood) for dummies .
(..by one of them..)

The thought of building a dinghy for oneself is both tempting and scary. I write this mainly to encourage myself to do it. I have drawn a few small pram-type dinghies (like Halibut, Medium Boy and Buddy), which are meant to make the threshold for getting started as low as possible. At the same time, I want the boats to be good, not just floating boxes.

I have done my best to design out difficulties when building.
Here are some key elements of the boatbuilding for dummies:

• ·         The designs are pram types with constant flare in the sides, both on 3-plank and 5-plank designs. This ensures that any bulkhead or frame can be made without any curves in them, meaning much faster construction and fitting.
• ·         The boats are built right side up, using three female, or cradle type moulds, plus the bow- and stern transom. The moulds, from plywood, chipboard, MDF or whatever are solidly fastened and aligned to a backbone plank, say 50 x 200mm and a bit longer than the boat. The bottom and side planks are screwed to the mould with thin, temporary screws. 
• Now the bottom and sides can be glued together ( see details on this  -  I prefer using polyurethane glue over epoxy). If needed, a few ‘stitches’ may be added to align the planks perfectly between the moulds. Hopefully I get away with duct tape.
• ·         Then the transoms. I will fit them ‘inside’ the hull, so the skin thickness has to be counted with when making them.
• ·         An important element is the use of a number of single elbow frames, just glued in place. The use of these will simplify building hugely, but will still ensure a strong and stable boat. Since the flare of the sides is constant, one may make one template for these elbows, which will speed up production of all the frames.
• ·         With the frames in place, one is free to install whatever one wants inside. With no inner moulds in the way, one may try thwart type, thwart positions and heights, as well as suitable positions for oarlocks. One can even step on-board and ‘test-row’ the boat.
• ·         Before releasing the boat from the cradle, one may then paint the inside, or one may wait until later. My boat is meant to rest upside down between use, so the inside will only be given ordinary paint after slopping on some thin preservative oil.
• ·         With the boat released from the moulds, it is turned upside down, the screw holes are dealt with and the chines rounded off a bit, prior to glassing the bottom. I may even add an extra 300mm wide strip of plywood along the centreline, to beef up the bottom before glassing.
• ·         A pair of skegs can then be fitted, if wanted.

Then paint, launch and row...

Well, that is the idea, so far  -  I bet it will be adjusted after having gained hands-on experience...

Arne

A planned small-scale test:

Hi David, Thank You for the advice to write to John directly for the dxf files which I have done. Luckily I can study the drawings of your tender to Sibling in the meantime which really seems to be much easier to build and it is a perfect answer to the cash prize competitions initial definition with free download to members including dxf files and now that Arne has said he is working on his boat for dummys instructions I am also looking forward to study them. John Perry seems to be retired and that may be the cause for no updates on his GP Pram design.

Good, Kevin.
Now I am pondering on writing a how-to on how to assemble my boat. I aim for the same basic way with either the Halibut or Medium Boy designs. I need to sort this out for myself, since I am a mediocre carpenter and have never built a dinghy before.
I bet it will end up looking like a sort of «Dinghy-building for Dummies  -  by one of them».

Arne

Edit: Here is a glimpse of a test setup I have in mind. By building right side up, one can finish the boat on the inside, thwarts, paint and all before releasing it from the moulds.

Then one can turn the thing upside-down and possibly glass the bottom, fit, skegs, or whatever.

(..see also Arne's sketches, section 6-24)

I wrote:

Graeme wrote:

I wonder if a more practical set of criteria would be not for a TENDER, but instead for a "JUNKET BOAT" - a general-purpose sailing dinghy which does not want an outboard, and which can be easily transported for those who are unable or for whom it is inconvenient at the time to travel to a junket under sail. Ideally it would be transportable on a car top (just) or with a very light trailer, and able to accommodate an air mattress/sleeping bag/canopy arrangement (just).

These two almost contradictory criteria intersect at about 12'.

Swapping boats and rigs at a junket, and letting bystanders have a go, would be rather fun.

The Welsford design [Golden Bay] (12'9") just sneaks in. All John Welsford has to do is modify the plan to provide an offset centreboard case and removable thwart. (Marcus reckons narrow side buoyancy tanks and short centre thwart which just drops into place for rowing. The ideal for me would be a single off-centreboard case incorporated into a side buoyancy tank, with a long swinging board for sailing in shallow bays, and for variable CLR.

All John Welsford has to do is modify the plan to provide an offset centreboard case and removeable thwart. (Marcus reckons narrow side buoyancy tanks and short centre thwart which just drops into place for rowing. The ideal for me would be a single off-centreboard case incorporated into a side buoyancy tank, with a long swinging board for sailing in shallow bays, and for variable CLR.

We don't need a sail plan. I am sure people like David, Arne, Sieve, Paul etc can come up with a suitable variety.

They row beautifully.

Here's mine

I agree absolutely, Graeme. This is what the JRA should be sponsoring and encouraging, a one-design Junket Boat, not a design for a tender. 

I agree, too, with the idea of having two side tanks with parallel sides that are just far enough apart to fit an air mattress of the Thermarest type in between. The removable thwart that can be slid fore and aft for rowing from different positions with one, two or three aboard, or removed for camping, is perfect. Given that, you have a versatile, easily built boat for Junkets, family pottering and minimalist dinghy cruising. Spot on. Again, there's no need to reinvent the wheel over and over again. The Golden Bay, with changes to the interior, fits the brief very well.

Hi,

I have found the complete documentation of John Perry s boat on the JRA Website which is really very detailed and the pdf is already downloaded in my  Boat Plans folder. The only thing is that I still do not know where to get the .dxf files to have a look at all parts and their dimensions.