Building 3 PD Racers at Duckflat

**Boatmik** · 26th January 2007, 12:32 AM

Time moves on so quickly.

This sequence starts on the Tuesday the week before Xmas.

Rob Badenoch is making up the mast step and mast partner - the two bits that hold up the mast.

One thing a lot of people (including lots of boat designers) don't "get" is just how much of the load is carried by the deck of the boat - even though it is only 5/32 (4mm) thick. The load is all lateral - so all that is needed is some way of distributing the load into the deck.

So I simply drew up a quite lightweight structure to provide enough glue area onto the underside of the deck. The surface area is provided by the two 45 x 19 (1 3/4" x 3/4") runners each side and the ply is used to make a torsion resisting box section as well as prevent the timber from splitting.

The same thing happens with the mast step on the bottom of the hull.

Image 1 - Here we have Robin Badenoch cutting the side rail for the mast step. Normally this is fitted before the bottom goes on but I decided that with three people helping with the hull assembly it was more important to get all the big stuff done. So now Rob is playing catch up. As well as making the parts fit the framing at each end it also has to be planed to match the curve of the hull bottom.

Image 2 - Here is one of the five drawings from the plan showing how the Mast step fits over the top of the framing. It also shows how the ply on the top of the step and the hull bottom ply form a box which means that the timber runners will flex as a unit - so it will transfer the high mast loads ( about 600 lbs lateral force with one person aboard or maybe double that with two aboard.

Image 3 - This is the first rail fully shaped to fit over the framing as well as matching the curve of the hull bottom. He now duplicates the rail.

Image 4 - Here is the finished mast step. The screws are used temporarily and are self tapping drywall/plasterboard screws. They are pulled out later and the holes are filled. The mast itself is supported on a pin that passes through the hole. The timber would tend to split because of the loads so a small piece of plywood is glued to the faces for the pin to pass through. A good trick if you have something that keeps splitting.

Image 5 - here you can see the excess glue coming out of the areas being glued. Generally I wait about 10 or 15 minutes before cleaning up because the timber can absorb some epoxy and suck some of the glue back into the join. Excess can be cleaned up with a putty knife or a gluestick sanded to a chisel point.

To fit the step to one boat took around 2 hours for the first boat and will be much faster for the following ones. Rob continues with the mast partner in the next post

**pawnhead** · 26th January 2007, 10:45 AM

It's a pity that this thread is receiving so little attention. After reading through it, and also your website, I can see that you're putting a lot of effort into getting people on the water for as little cost as possible. Some great ideas there with building your own mast, and poly tarp sails.

When I was a kid back in the late sixties, my old man and I built a Manly Junior, then a Cherub, so your guide brings back memories for me. I did it with pocket money, and money from my paper run, but nowadays you'd have to see your bank manager to be competitive.

Still, I wouldn't mind one of these, or better yet, one of these, if they'd worked out how to build them so they wouldn't fall apart.

I'd love to get back on the water.

Good work Boatmik

. I hope the class takes off here. I think my boat building days are over, though I might buy an old cheap Hobie cat and a fibreglass kit one of these days.

edit: - Oh, and a good life jacket (just in case my fibreglassing skills aren't up to scratch

).

**Wood Butcher** · 26th January 2007, 12:10 PM

I think it's a bit unfair to say that this thread gets "so little attention". Fair enough there is only 16 or so replies but almost 900 views there are a lot of people watching this thread.

Boatmik,

I do agree with pawnhead however that you should be commended for your efforts in promoting a cheap and simple boat to get people back into sailing. Well Done!

**pawnhead** · 26th January 2007, 12:17 PM

Originally Posted by Wood Butcher

I think it's a bit unfair to say that this thread gets "so little attention". Fair enough there is only 16 or so replies but almost 900 views there are a lot of people watching this thread.

Well before mine, there was only one reply to Boatmik, so I thought I'd give him a pat on the back, and I reckon it would be a good idea for some of the people viewing it to acknowledge the effort he's putting in if they read the thread.

It's always nice to get a positive response to a thread that you start, and this one is a beauty if you're thinking about building a cheap boat that performs well.

**Boatmik** · 26th January 2007, 05:46 PM

Cheers Blokes!

Much appreciate the comments.

There is a lot more to come to document some more of the detail.

There are now 9 Australian PDRs registered and 8 are OZ PDRs - and lots of plans sold. So the pics and description will be there for those people as they come on line.

And pawnhead - I'm quite interested in foilers too - the Moth class with its weekly racing schedule has quickly worked toward a really successful setup.

Maybe if I get some money together I'll build something resembling the attached sketch. A little offshore foiler. The moths work because they keep things really simple and light - that's what I'm interested in too but with wood construction.

If there is weekly racing for a class of foilers to go offshore then they would improve hand over fist in a short time just like the moths. I haven't done any calcs for the boat in the foiler sketch (as anyone can see by the smallness of the crossbeams!) but I reckon I could keep the weight of the whole rig down to around 500lbs using ply and timber so the foils could be simple as well.

If regular people can't afford it then it deserves to die - which is what happened to the Hobie despite the wonderful concept. Execution was a bit dodgy in that case - the hull attachments for the foils are not strong enough over the medium and long term by all accounts

Thanks a lot again chaps.

MIK

**Boatmik** · 22nd May 2007, 12:19 AM

I just realised the end of this thread was just floating around.

Anyway we did make the deadline for the Goolwa boatshow.

We had 5 PDRs there - the two yellow ones from Qld, the one yellow one from SA, the pink one and the blue one.

I was poised to take out the first national PDRacer Championships - assuming I could win enough races ...

To find out how the racing was blown out by excessive wind but still some things puddleduckian happened see this thread
http://www.woodworkforums.ubeaut.com...834#post496834

MIK

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