PD Racer South Africa

DriesLaas said:

Just a quick pic of the complete PD racer hull kit.

It goes together with a little fitting ( you have to file out the fillets left by the round cutter. I can remove it with the router, but then you are left with a slightly larger cutout than absolutely necessary.)
It looks very promising at this stage, I will try to start assembling over the weekend.

The plywood we got is quite dense and stiff. It is about 750 kg/m^3, and the hull kit weighs a hefty 40 kg (88 pounds) of plywood mass.

What is this weight normally? If it is grossly overweight I must try to save some mass elsewhere.

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If your boats come in at around 100 lbs, they are not that exceptionally heavy. Some in the fleet are much lighter, but those were made lighter due to lighter wood that was readily available and at relatively low cost. One I designed dispensed with the air tanks altogether and replaced them with one gallon milk jugs. But weight was added in other areas, such as an elevated cockpit sole, and it ended up weighing (on paper) 125 lbs.

I went thru my old records and the 9mm ply that I got from the same supplier was around 14 to 16 kg per sheet

this 6mm is heavy BUT from what I saw it is really good quality
batches do vary but the material that you have there is going to build some REALLY fine boats
on all the edges that I inspected there were no voids or overlaps
I was very impressed with the marine ply

now that I have slept over it
I must say that a well designed and cut kit like this one is fantastic

I think that it could be assembled as is
join all the pieces together with epoxy glue
cover all the surfaces in epoxy
FINISHED

no extra wood - no fillets - no glass - nothing extra
the plywood is very stiff over such short distances
and the finger joints makes this a very rigid construction

ulitimately Dries will have THE BEST PDR kit available in the WORLD

In my childhood days I was a very keen "Airfix" model aeroplane builder, all the WW2 planes. I had many of these planes hanging from my ceiling, and with a gentle breeze blowing thru the room it was magic to lay on the bed and dream of flying away on one of these little planes swinging on a piece of cotton thread.
Some of the guys here will remember those "kits" - everything in one box. You had to carefully break each part out of a framework and the glue the pieces together.

That is what this PDR kit is all about, glue the pieces together and you have an instant boat. This system works so well that I firmly believe that much bigger boats could be built this way. The key factor is that you have to have a 100% detailed CAD drawing. Not only did Dries draw PROPERLY he really pulled this one off. Top job!!

Calling Manie and DriesLaas;

Now that the design and prototype is done, please refer to post #24



Nice work gentleman.

You can definately have one
but the "donation" is kinda
shall we say
oh what shall we say
oh dear
f@rkit dunno bout dat

anyway keep you posted

Hi Dries, Manie

My boat weighed in at 50kg exactly with two 7" side air boxes. I used 4mm for the sides and 6m for the bottom and deck.
Man and now I have that terrrrible itch again.

I want to build a 16' tacking proa, ama and lateen sail, the works.

I even built a balsa model 1:12 scale this afternoon, see pics below

I am besotted with boat design, where is it going to end?

I am afraid the only known cure to this affliction is to buy a large screen TV and watch copious amounts of mindless sport, like blue bulls rugby for example.
After a while the stupidity permeates into the brain of the watcher, and tends to stifle strange tendencies towards creativity.

Beware however that your innocent remote control should not inadvertantly stumble onto eighteen foot skiff racing in Sydney Bay Harbor, or some VOR racing footage.

If this should happen, I humbly suggest giving in to the urge, opening Fundamentals Of Yacht Design on page one and locking yourself in the garage. Because you are lost to mankind.

DriesLaas said:

Beware however that your innocent remote control should not inadvertantly stumble onto eighteen foot skiff racing in Sydney Bay Harbor, or some VOR racing footage.

If this should happen, I humbly suggest giving in to the urge, opening Fundamentals Of Yacht Design on page one and locking yourself in the garage. Because you are lost to mankind.

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Its OK, relax - Beer can fix this part! But you just need enough to get past the point of believing you are about to redesign the eighteen foot skiff or VOR70.

Beer I have plenty, time, I have little of.....Dreams of a selfbuilt boat too much. Lying awake at night with visions of boat structures and frames is overwhelming. So I suppose that I will be opening the purse strings soon. The plan is to build two eight foot polistyrene Ama's coated with poxy and glass, then at least take a polyprop plastic kayak sailing

Hi Dries
how are you
any news on the PDR

Hi Manie,

Nothing to report. The hull panels are stitched together, and then I was overtaken by more pressing matters.

Should get back to building next week.

Regards,

DriesLaas said:

Thanks for clarifying that, it had me going as well.

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It could have spared me the trouble to think it out if I'd found this page earlier

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BTW Manie, when in tow as a dinghy behind the Micro, isn't the PDR's bow transom gonna pound in a chop . . ? ?

Cheers,
Angel

DriesLaas said:

Should get back to building next week.

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Hey Dries, next week is now, how's the build going, did you find time . . ? ?

Good luck !
Angel

I spoke to Dries on the phone and he is SNOWED UNDER with work
at least somebody is very busy

There is movement in the workshop again.
It has been a very tough and long year. Nowhere close to out of the woods yet.
This little boat is getting to work on my nerves now, I have to finish it. Amazing how just fitting a pannel whilst quietly swearing to yourself can relax you.
Anyhow, the hull is in 3-d shape, and I have requested a hull number. The good vessel will be called "Who Ducks Wins", and has every chance of being finished before I lose momentum again.
I plan something revolutionary with the rig, which to my knowledge has not been done yet. Whether it will work, only time will tell. It would have been real boring if we knew all the answers beforehand.
On another subject altogether, has anyone thought of sailing thr PDR the wrong way forward. It sure looks to me as if it might go better that way......
The hell with it, I'm setting my boat up to sail either way.

I may also prep the side tanks to act as water-ballast, and in that case we will be forced to stick her on foils just for kicks.

So many little decisions to work through.

DriesLaas said:

...On another subject altogether, has anyone thought of sailing thr PDR the wrong way forward. It sure looks to me as if it might go better that way......
The hell with it, I'm setting my boat up to sail either way.

I may also prep the side tanks to act as water-ballast, and in that case we will be forced to stick her on foils just for kicks.

So many little decisions to work through.

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I have. I drew my first PD design with a movable mast step and rudder, so the ends could be swapped. I thought it would actually go faster backwards, as the Center of Buoyancy (CB) would be further forward to counteract the downward thrust vector of the rig.

Traditional working scows built in America were built this way, even at a time other work boats types had their CB's further aft.

My design was never built and probably never will be, as it would no longer be class compliant.