Thread: Mystery Oz PDR prototype

Yes, avoid making your mast out of anything with the word 'pine' in it.

As for safe, yes, nothing was hurt apart from the mast and my pride. There is nothing so sad as the slow, breeze-blown trip back to the shore, in full view of all the lakeside residents.

We built a set of masts out of clear pine for the duckflat boats. And they have been fine too.

Fingerjointing and knots are probs.

MIK

Something I did notice in the short time I was out actually sailing, particularly with two people in the boat, was how the off-centreboard now gets in the way when you want to sit on the port deck.

So, nice clear well up the guts of the boat with the centreboard moved into the 'MK III' position but now I don't seem to be able to get to sit in the 'sweet spot' that stops the transom dragging in the water or the bow digging in on the turn. Might only be a problem with two adults in the boat. In the short but exciting run with just me in the boat I was busier than a one armed wall paper hangerer and didn't get to focus on the finer point of tuning my CG!

I guess it's all compromise, as with most things in life.

Howdy Andy,

It is a two person problem. The transom does drag a bit with two aboard. Not so much when the boat isn't moving, but as soon as it is then it creates a wave trough under the middle part of the boat so the boat sinks down.

It happens even when single handed, but there is enough clearance.

I know there are quotes about XXX displacement for the boat, but they are loaded in still water with the corners of the transoms just touching the water. They might load barges like that, but not sailing boats!

The boat still moves along OK with two aboard, but the thing is to be sensitive to the boat. Having the bow transom digging in is real slow - you can hear it and feel it. So to just barely avoid that is the aim with two aboard.

Best wishes
MIK

I've nearly finished my new mast, this time using Australian Hoop Pine. This is from various sources, though mostly Boatcraft Pacific:

An Australian native pine. Native to the drier parts of rainforests of Queensland and Northern NSW in places that have rocky soil with lower fertility. Most of the timber that is used commercially now comes from plantations. The trees grow to 60 metres tall and can live for 450 years. The trees grow slowly and usually very straight. The first major use for the plantations was to provide replacement masts for the sailing ships, indeed a small portion of a plantation established for that purpose survives in the Brisbane suburb of Sherwood.

From an ethical, sustainable point of view, Hoop Pine is streets ahead of most of its plantation-grown exotic softwood counterparts. The best is #1 Clear Grade Dressed All Round Hoop Pine (I used this). This is the finest, most defect free grade available. This specification states that knots, tight or otherwise are not permitted, sloping grain is not to exceed 1 in 5, no pith can be present, no resin pockets, or bark pockets, and it is not to have any checks.

According to Bootle, "WOOD IN AUSTRALIA, Types, properties and uses", Keith R Bootle, First Published 1983, McGraw Hill; It has an Air Dry Density of about 530 kg per cubic metre and its mechanical properties are very similar to Douglas Fir (Oregon, Pseudotuga menziesii). It is very suitable for boatbuilding, is easy to work and it does glue well. It is suceptable to rot, so normal precautions need to be taken. Its only limitation is that it is not suitable for steam bending.

You can see in the picture where, as I haven't got enough clamps, I've used the clamp and tape method. Put on your clamps, tape everything up, move the clamps along, tape again, and so on...

I'm also up for some sail repairs. The top of the sail seems to have been under some pressure and I think I'll add a canvas reinforcing patch just to keep it all together. I also found some plastic grommets. There was only one packet of them left at Bunnings so I bought it and the recommended brass ones. I put the plastic ones towards the bottom of the sail and the brass ones at the top (you need more than 10 for a sail).

I bought one of those punch-and-die kits for putting in the 'brass' eyelets/grommets and found that even though they had less contact with the water being at the top, they still rusted. Obviously just a thin brass coating that the salt water can get through pretty easy. The plastic ones are less than $2.00 a pack of 10, you don't need special tools to put in place and they have already outlasted the brass ones.

Anyway, just matter of varnishing the mast, patching the sail and I'm back in the water.

Excellent work.

I am not sure about how the plastic eyes will go, but nothing too dramatic will happen if the top and bottoms are metal.

We found the brass plated steel trick with our Mk1 sails. A tricky trick.

You can get proper brass ones from sailmakers, but camping and outdoor stores often have bags of them. The ones from Primus are quite well distributed in OZ and include the tools (except for the punch) for quite a cheap price

Best wishes
Michael

Mast is finished and looks wonderful. Now if it would only stop raining I could take her for a sail.

My regrets at buying the cheapest version of polytarp for the sail is continuing to build. I was determined to stay with the philosophy of 'thriftyness' for the PDR but I should have bought the $60 polytarp rather than the $20. The stresses on the eyelettes used at the top of the sail and on the downhaul are showing already, with the poly tearing after only one and a half outings (half an outing due to broken mast). The tears were happening with the plastic eyelettes and the metal ones, so I don't think eyelette material has had anything to do with it. I've gone fully plastic now.

To compensate I've put in a couple of tough canvas patches on those two parts of the sail. Hopefully it will solve that problem.

I've also thrown in a shot of the break point in the original mast, just for 'forensic' interest.

If you're wondering what the white bits are along the stitching, I used masking tape instead of pins to keep the seams in place for sewing. I figured after the first time in the water they'd get wet and fall off. Surprisingly, they are proving a little more tenacious. Probably outlast the polytarp.

I've realised that I've sort of hijacked the thread from being about the MK III to being about my boat. This is the last one I'll post here and if I've got anything else to talk about from now on that doesn't have anything to do with 'MK III' stuff, I'll stick it somewhere else.

I can move yours all into a separate thread if you like.

MIK
(I have the power)

... no, that's ok. If I want to tell anyone any more stories I'll start a new thread. My plan is to disappear off to quiet anonymity and never be heard from again.

Personally I hope not. But whatever you are comfortable with!

MIK