Thread: Building the OZ PD Racer - now renamed the OzRacer

By the way, MIK, did you get my off-list PM re PDR plans & lug rig ?
AJ

NO I didn't AJ ...
MIK

Just tried again - using the 'contact me' link on your web-site to an ozemail address.
(tested it from centralops.net - hopefully iiNet haven't classed it/me as spam..)

Anyway, I got a set of OzPDR plans off Ted this week. Not intending to build right away, but
I've accumulated a significant amount of 4mm left-overs from kayaks that will need a home
eventually.

While the PDR as a boat doesn't turn on any lights for me, the whole thing
about what is possible for sailing with the PDRs, does.

Plus a few other bits drifting in
& out in the background. For example, I know a bloke runs a men's shed. At the moment
their projects are ultra-cheap - scrap wood stuff. But down the track... something about
sailing clubs operating out of a garage... plus Compass's youth programmes on the GIS
thread.

Possibilities, possibilities....
Anyway, I was after the lug rig drawings.
cheers
AJ

Look AJ ...

This is putting your finger on the pulse of what I try to do. In a way the boats are not important.

Originally Posted by b.o.a.t.

While the PDR as a boat doesn't turn on any lights for me, the whole thing
about what is possible for sailing with the PDRs, does.

It is exactly the same for me - that's what I think too. But this is where the boats come into it ... if they don't work REALLY well and are not INSPIRING then these other things that come from them lose their power.

And some examples of other things ...

Plus a few other bits drifting in & out in the background. For example, I know a bloke runs a men's shed.

At the moment their projects are ultra-cheap - scrap wood stuff. But down the track...

something about sailing clubs operating out of a garage...

plus Compass's youth programmes on the GIS
thread.

Possibilities, possibilities....

YES - GO GO GO

Take any chance to make this life thing bigger!

any help ... just ask

MIK

Today was the maiden voyage of my boat.
There was almost no wind, but for a beginner like me it was OK.
Maybe a bit more would be better.... next time....
It was a great experience.

Beautiful.

Why wasn't there anyone else on the lake on such a beautiful day for sailing?

Gyula Ferencz (hope I have remembered your family name correctly)

That is one great looking boat!!!!

The sail looks fantastic too. I have seen professional sails with a worse shape than that!!!

For those who don't know the whole story ... Gyula was up against a whole heap of problems about getting materials in the early days of the project. EVERYTHING was difficult - epoxy was available in 200 litre lots for example!

Many weaker men would have crumbled ... but Gyula kept going and now ... this fantastic looking boat!!!

So cool.

Thankyou Gyula!!!! Thankyou

MIK

MIK

G'day Michael
A question which I can't see asked/answered elsewhere in the forums.
Given that most joints seem to have a cleat associated with them, are alternative
glues to epoxy acceptable ?

Question sparked by Gyula's problems getting epoxy, combined with talking with someone
from Goolwa the other day whose old rough-&-ready boat from Goolwa WBF was still in use
after 10+ years, held together with Sikaflex. All they'd done was tidy the chines (removing or
trimming the copper ties) & gunwales & painted it. Then later that day I saw Sikaflex at a
large hardware shop for less than $10 a cartridge.

Anyway, it occurred to me that as 2-3 cartridges of Sika were enough to glue and seal
the rough edges & large cable tie holes on the rough & readies I've done, it would probably
be enough to build a PDR. 3 cartridges of Sika is much cheaper than 3kg of epoxy plus
glass tape.

If $$ or availability were a major issue to builder, would it be sufficient to pre-prime all
components, then glue & screw all joints with Sika (or even Purbond), ensuring enough
Sika used to squeeze some excess out of the joint. All cleated seams to be sealed with
a tiny fillet of Sika, non-cleated seams with a larger fillet. Then topcoat over the lot.

What thinketh you?
cheers
AJ

Good question AJ,

Lets skip sika for a moment ... but I will come back to it.

Basically I specify epoxy because I know it works close to 100% of the time. It has two significant advantages in terms of structural integrity
1/ It is gap filling
2/ It only requires low clamping pressures.

Most of the glue alternatives, either the moisture cure polyurethane or the modified PVAs that are suitable for exterior use have these two requirements according to the manufacturers.
1/ Not gap filling
2/ Require "moderate" clamping pressure.

Most amateur boatbuilding doesn't fulfill this standard ... so given the reliability of the epoxy ... I can't tell people to go another way because I have the responsibility that the boats work ok.

HOWEVER ...

This doesn't mean that successful boats have not been built using other glues. Most of the US built PDRacers use glues other than epoxy - though most built there to my OZ plans do continue to use 'pox.

One OZ built using alternative glues that way did have the bottom of the hull delaminate from the centreboard case ... but it had to hit 3 underwater logs at speed before it happened and the lurch of the crew's foot close to the case may have been as responsible as the impact ... but I don't know the contribution of the glue type.

But a caveat. When we were building racing dinghies in the '60s and 70's we also used non gap filling glues such as urea formaldehyde or resorcinol ... often the well loved Selley's 308.

Usually the boats were nailed with barbed ring nails with screws in some areas.

The boats did require quite a bit of maintenance though you could expect a season or two of relatively trouble free use .... after that there would start to be inevitable leaks leading to a major repaint and repair about year 3 or 4.

At that point the boats were usually glass taped using 2" (50mm) glass tape and polyester resin to try and fix the leaks. Polyester doesnt' really stick to wood well - so I owuld probably be reckoning to use epoxy these days.

At some point someone worked out it was more sensible to put the glass tape on when the boat was built. This maybe brought the relatively leak free period up a bit longer. But still problems with paint breaking down and the fastenings moving a bit breaking the paint seal over the top meant the maintenance cycle was a bit hefty and problems still occured like the glass tape splitting or being sanded down too thin during successive repaints.

So I would be suggesting for experiments with alternative glues. Consider using glass tape on the hull joins as needed. Consider using epoxy rather than polyester for the tape.

Or what about just gluing the boat with epoxy anyhow and just forgetting the epoxy coating? You are going to increase maintenance and reduce the life of the boat - and maybe that is a sensible decision for some who are building PDRacers - but I would rather not see that happen to any of my more "fancy" designs.

The reason that epoxies took over from these well used glues was the drop in maintenance and the reduction in water absorbtion. Suddenly a fully coated boat could eliminate fastenings and get very extended durability with little or no maintenance over many years.

Like the Biting Midge's GOAT - now needing revarnishing at 14 years and the hull painting is still in perfect condition. This might be a slightly exceptional case, but most boats are not too far off that.

You pays your money and takes your pick.

Now with Sika ... it is gap filling, but does require the special primer to have an adhesive effect. Again ... I can't make any guarantees that it will or wont work so I won't be advising people go that way. It can be adequate as a glue, but problems of slow cure (and you don't know just how well it has cured in the joints (asked Dan here and he suggested a week to cure), being very messy, probably needing more cannisters than expected, problems with sanding - it does but you want to finish everything as much as possible before it cures, and finally because it can stretch so much any paint over the top will crack well before the sika gives way.

So ... this conservative designer is saying to "stick" with epoxy.

Good question though
Michael Storer.

Thanks Michael
It might be something to experiment with on a boat made from scrounged second-
hand construction ply & discarded pallets. Naturally, one would use many permapine
screws & leave them in place, which should help the boat remain more-or-less boat
shaped.
cheers
AJ

Michael,

I just wanted to check your timber list calculations for 19x19mm framing for "bulkheads and misc" (on page 5). Is 17,500mm correct? I did some rough calculations and thought 32m of 19x19mm strips is an awful lot of timber for a 2.5m boat. Could it be 1,750mm rather than 17,500mm?

If you add up that list of the 19x19mm strips required, I get about 32,950mm. If there is a mistake, you get 17,200mm. The latter seems more reasonable to me.

Cheers,
Mark

Howdy Theodor,

That looks about right ...
just the gunwales are 5000mm

to frame the bow transom is 3500mm

Can you see how quickly it will all disappear?

I am always a little surprised about timber lists too.

MIK

Originally Posted by Boatmik

Howdy Theodor,

That looks about right ...
just the gunwales are 5000mm

to frame the bow transom is 3500mm

Can you see how quickly it will all disappear?

I am always a little surprised about timber lists too.

MIK

I think half my problem is that I have little idea what these technical boating terms are. I know what 'gunwales' and 'chines' are, and even now I even know what a 'carlin' is. Its just a little tricky to see the correspondance between the timber list terms and what you actually build. I am unsure if you use many of these technical terms in the plans (which I think is a good thing).

By my calcs off your drawings, you only need 1900mm of 19x19mm wood. How are we getting different values here?

Mark

Just working out again now Mark