Monday, January 2, 2012

Rigs and Reefing

Good article here by Jim Michalak about small boat rigs and reefing.  It could apply to those that want a shorter stub mast rig.



I gave the new crossbeam hinges on the Va'a Motu a good workout this week.  Some steep five foot waves and a rip roaring surf couldn't make them squeak so I'm feeling good about them.
I am however going to try a different rudder system.  I'm getting more side bend from the rudder pivot area than I like and am also annoyed when a rudder kicks up just a little and makes steering really hard.  So I'm going to build a cassette rudder that works like a daggerboard.  This won't kick up so easily if you hit something but it has several other advantages.  It will be just as easy to steer with it partially retracted, it'll be totally stiff, and I'll be able to adjust the amount of weather helm on different courses by adjusting the depth.

6 comments:

Wade Tarzia said...

Interesting comment about your rudder. I have noticed a considerable bend in my stern rudder cheek-piece. On a nice down wind run in 3 foot seas, I would be surfing up to 7-8 knots and really leaning on my tiller to keep tracking, with disappointing effect. Eventually I steered by looking backward for a long time and noticed that the bend of the parts seemed to be subtracting from the angle of the kick-up rudder. Annoying ...and dangerous if I cannot recover and go into a broach. I guess I have to stiffen the cheek-piece, but I am also going to try another quarter-rudder, steering-oar style, in some way.

Jim Finch said...

I am having similar issues. On my first sail in my Ulua, the rudder cheek deformed and rendered the mechanism useless. I remade it with stronger material. On the second sail the gudgeon and pintle hardware deformed, with the same result. I really need a strong rudder mechanism that i can make myself, I don't need a kick up mechanism. We had to demast the canoe and paddle back.

Scot said...

Yes the rudder box can be tricky. Most dingheys that use a pivot rudder have very strong rudder boxes and it not unusual for them to be made from 1" marine ply. The stress on the pivot box is increased if you allow a trailing rake on the blade then the stress on your rudder box is significantly . So I re-drill the pivot point so that fully down the blade has a slight forward rake. This gives a neutral helm and reduces the forces on your rudder box. Many sailers use a thin metal pin to ensure that the blade stays all the way down and in the event of running aground the only damage is a bent pin which is easily replaced. Raking the blade too far forward can cause cavitation so just a bit of forward rake and consider altering your blade design in line with my previous comment.

Good luck with your design and development

Scot

Robert Terry said...

Glad to hear the crossbeam hinges are holding up. After spending Friday at the beach watching the EC contestants prepare for launch I am motivated to enter ASAP. I have Wa'apa plans and it is high on my list of boats to build and enter.

Disappointing news regarding the rudder though. We must have a kick up rudder in our skinny waters, what reinforcements could you recommend for a stern mounted kick up rudder for Wa'apa?

Gary.Dierking said...

The new rudder does kickup just like conventional pivoting ones, and then it returns to vertical all by itself.
It's the best rudder I've ever used and has been in use here and Australia for 40 years.

Gary.Dierking said...

The new rudder does kickup just like conventional pivoting ones, and then it returns to vertical all by itself.
It's the best rudder I've ever used and has been in use here and Australia for 40 years.