08 May, 2011

My rudder and I.

Pizza Cutter Rudder Blade
Rudder Arm: Tiller
I'm humble enough to recognize that I will never ever be a DIYer -- let alone a boat builder.  But I was keen to retrofit my paddleski so that I could control it 'under sail'.
Let's not deal with the sail and rigging question for the moment as I'm wanting to experiment some more with my devices...and the perspective anyway is all a bit eccentric...esp for the sailing purists to embrace....
However, it was very clear that my stubby little craft -- 2.4 m long and beamy -- when moved forward by the force of the wind -- prefers to come about at every opportunity. In fact 'under sail' it tracks badly. I suspect the creature wants a tail to drag behind it  when the reality is that  the captain and galley slave-- c'est moi -- sits at the rear and there is not much behind . It's a kayak that grew up a midget. 

Not much behind
So I needed to find some way to keep the thing on my preferred navigational course. Since this is all experimental, and the craft wasn't designed with sailing in mind,  the fun lies in the challenge: 
"making a silk purse out of a sow's ear."
I had a few options:
  • A skeg : Adding a skeg to the this sit-on-top craft would improve its tracking but not facilitate flexible navigation. A skeg would also get in the way across the sand banks and when landing and dragging the beast through the shallows in my very shallow locale. 
  • Attaching a leeboard. While leeboard would not allow for navigational choices it presented similar problems to the skeg. Also, since my hull is a catamaran like twin hull design I don't need the lateral stability as a roll over or sideways drift is very hard to engineer. My sides also slope diagonally to the water line.
  • Adding a rudder. Kayaks do often use rudders to get about but often in the case of sit ons -- ones controlled by  the feet of the paddler via a pulley system.  They usually descend directly down when in my paddling preference I may be a kilometre from shore but may have less than 70 cm below my waterline. It's shallow in these parts.
With no desire to invest in some of these tech options that may be overkill or not work on my little boat, I thought the rudder option gave me more bang for my buck -- or so I have imagined. In fact I spent nothing new on it at all -- no bucks to bang with.  I simply cobbled a rudder together from found stuff.
  1. Three bamboo canes
  2. Strapped together with zippy ties
  3. To a blade that used to be a pizza cutter 
  4. Held in place by a bungey cord. 
  5. And with a short end of aluminium tubing that carried 'the handle' to one side.
So this is Rudder Mark I . 

And it works!

You coulda knocked me over with a feather! With one hand on the tiller I have great control over the paddleski's direction. By running the working arm diagonally to the right I can use my right hand to pull the rudder left and right for steering purposes leaving my left hand is 'free'. When not in use, and when landing or in even shallower water, I drag the rudder arm toward the deck and clip it into a semi horizontal plane above the water line.

Kon Tiki: rudder at left 
What surprizes me is that despite the fact that the pizza blade is so shallow -- it, in fact , functions like a short skeg like you'd find on surf boards -- it allows just that cutting edge slice in the water that gives me excellent control.  And since the craft it weighted toward the stern anyway (thus the preference to come about) and is so short and stubby, the rudder positioned between the two cat like hulls acts as a critical pivot deciding direction -- like  tail on  fish .(I reminded of the rudder on Thor Heyerdahl's Kon Tiki  -- not that I'm planning to sail across the Pacific Ocean).

My rudder lives off an arm which functions like a feral oar  so I can sail about  with it 'down' in 30 cm of water. I can even churn the waters with it and generate some propulsion akin to coracle paddling.

However, I need to sail some more to see what awaits me... my rudder and I.