Much head scratching, napkin sketching, and general brain-storming has brought me to the point where I am. Casting patterns have been made for all four pieces of rudder hardware. I think they'll work nicely. I have a list of functionality issues that have to be addressed in order to consider this a success.
1. - Rudder must ship and unship safely, securely, and reliably without tools.
2. - Rudder must operate fairly precisely, but with enough "slop" to allow for the fact that upper and lower fittings are not in line with each other.
3. - Fittings must look proper for this application- yachty enough to be worth the time and effort but rustic enough to appear proper on what was, traditionally, basically a farmer's boat.
4. - Not ridiculously expensive.
I'm pretty sure I have addressed the first three. We'll soon see about the fourth.
As you can see in the photos, there are four fittings - two gudgeons (mounted to the stern of the boat), and two pintles (mounted to the rudder blade). The lower gudgeon (V-shaped with tapered edges) is to be riveted to the lower stem at a point roughly 2" below the waterline. The upper gudgeon is to be screw-fastened to the stem just above the point where it goes from tapered to square. Both gudgeons will be bored for a length of 5/16" bronze rod. The rod will follow the curve of the aft stem from the lower gudgeon (brazed into this fitting?), and pass through the upper gudgeon. Rod will terminate at a point (to be determined) some distance above the upper gudgeon.
The lower pintle pattern shows how I plan to ship and unship the rudder. The "split fingers" allow the 5/16" rod to fit between them. Rotating the fitting 90 degrees grasps the rod securely. The upper pintle is bored for the 5/16" rod. Shipping the rudder will work as follows: with the rudder lying on its side, engage the rod between the fingers in the lower pintle. Rotate the rudder to vertical and drop the upper pintle onto the rod that projects beyond the upper gudgeon. The lower pintle remains free to slide up and down on the rod, but as long as the upper pintle is engaged it can't release the rod from between the fingers.
It's not an original idea. I copied it from other boats (Nutshell Pram, Dyer Dhow, and other small craft) but have not seen it done on a boat of this size. I may have to come up with something to keep the rudder from floating up and disengaging the upper pintle. There might be enough mass in the portion of the rudder that is above the waterline to overcome the flotation of the immersed area. I don't know, yet.
Will I be able to ship/unship the whole shebang from inside the boat? I doubt it, particularly since there will generally be an inflated bouyancy tank in each end of the boat whenever she is used for sailing (for any distance, anyway). The good news is that if I have to unship before beaching I can do so in ankle-deep water. If I have to switch from sailing to rowing while underway the tiller will be lashed in place on center or handed to a crew member.
All in all, I think I'm good to go.
In other areas of the project momentum waxes and wanes. I was fortunate to get a few days of rowing in last summer. Build-up of finishes continues. Gooseneck is installed on the boom. Shrouds are spliced but forestay needs another go 'round at the think tank.
We got a new sill under the barn last summer. Part of that project involved re-building the door opening. The doors are back in the opening but are currently screwed in place in front of Dark Secret. Hinges are being welded and will be installed shortly. At that point I can get her out of the barn and into someplace warm enough to tackle the last couple of coats of varnish. If all goes according to plan (good luck with that), I'll be sailing this spring.
More to come...
No comments:
Post a Comment