22 July, 2011

Paddleski mock up

With anything I could find, today I created a  sailing rig for the paddleski. I wanted to see how my intended rig design would look and 'feel' in a mock-up situation. 

The experience was better than I had expected.

Today's setup was very daggy. I used bits of bamboo I lashed together; and an old tarp that was useless  against the weather...

But I learnt a few things:

I was able to confirm was that I can feasibly carry a mast somewhere around 3 metres (3.1 metres I suspect) in height so long as the fall of the sail is no longer than the craft. I suspect that 2.1-2.2 metres may be my length limit on a craft that is 2.4 metres long.

That's a greater sail area than I had hoped for.

This realisation was expedited by the fact that I have had a very special mental moment in regard to the step for the mast. Since my intention is not to create any more holes in my plastic boat other than those it was born with, I wanted to rig with the 'attachments'  that were already on offer.

Upside down crutch
In the case of the mast: I'm using the carry handle at the bow  by deploying a split setup with two prongs of a crutch embracing and supporting, what will be, a 3 metre long bamboo cane. The setup will need more work but it should be a solid fit that also allows forward and aft movement (so that I can pivot the sail -- raise and lower it -- depending on the wind).

I also discovered that the bent arms of a crutch are ideal for bracing the mast  as they curve in to attach. So crutch arms on both sides of the deck  hold the mast in place and prevent lateral shift.

That leaves me with the need to incorporate   3 bamboo struts: one for the mast braces, one for the rudders, and a third to  hold the sail rope clear of the hull.

This third strut is also used to hold the passive lee side rudder aloft so that it does not drag in the water but just skims the surface -- serving, perhaps, like  an ama on a outrigger or as a leeboard.

That may make me 'over-ruddered'  but my experience on the paddleski suggest that what goes on behind really helps the forward navigation. I also went back to a two rudder setup because I'd need to deal with the complication of changing one rudder from side to side at the same time as I shifted the sail across when coming about. Given that it was clear that tacking or gibing with the sail was going to be easy -- switching rudder sides with one rudder was,  in contrast, going to be quite  difficult.

Another work around may be to switch to using a deep shafted traditional outrigger paddle for both paddling and steering because the shorter shaft and 'T' handle will make it easier to both paddle while the sail is up and use the blade to steer either side.

So that's the rig:
  • three struts
  • one mast
  • two mast braces
  • a sail
  • two rudders.
  • and a rope to hold onto, or tie down, the sail.
The plan is that all this will slot in and clip on using zippy/cable ties and/or stretch cords.  I am experimenting with re-usable zippy ties and they are great. So set up for sailing would take less than five minutes.

The sail comes cheap -- depending on quality -- around $15-$28 -- Polytarp from SuperCheap Auto.(See Polytarp sail making DIY bookmark links). My main challenge is sourcing the bamboo...

My budget:All up for less than $50. 

But this is a rig that could be put together in a morning: cut and seal the sail; trim the bamboo; lash everything together... cast off.

This mock up was mounted today in winds with12 knot gusts and there was no inclination whatsoever that the craft would capsize into the sea of ...lawn. So I expect that I can pack on plenty of sail, especially with my body weight on board, without fear of going under.

My one pressing problem is: what do I do with the rig when I'm not sailing? I know I can 'ship' my rudders easily enough (although I get much better  tracking with them in place), but the mast is sure to be longer than the craft. It may be best practice to wrap the sail around the mast, leave it upright and paddle...then unwrap the sail when the wind freshens.I also need to carry a two blade paddle on these jaunts.

So I tried it: I wrapped my daggy 'sail' around the mast and laid it flat along the length of the craft and with the stern strut in place as a rear brace the paddleski can still be paddled. The mast extended from my stern by 80 cm but that's no big deal. 

Nonetheless, today's exercise has made me confident  that this rig may actually work and in a very short space of time I'll be canoe sailing Deception Bay at speed. It won't be fast sail, but with those prevailing winds behind me navigating north , at least, is going to a be easy. Sneaking up on the stingrays and maybe, when breasting the corner into Pumicestone Passage and traversing the sea grass beds, surprising a Dugong cow and her calf.