Still Thinking About Rigs

Still pondering. Here are my latest, perhaps not best thoughts.

My first thought is to recall that I am building a light weight small catamaran.  And it should have a lightweight easily handled rig to go with it.  Call that the requirement the boat has for the rig.

So with light weight and ease of handling as my primary concerns I can evaluate rig option based on these criteria. Right? For the following I figured any boom meant moderate weight.

Here is a go:

Soft-wing sail: Heavy, Easy to handle.
     Lots of hardware aloft.

Junk-rig: Moderate weight, Easy to handle
     Many battens and associated tackle adds to weight.

Luff Pocket Boomless: Light, Easy to handle
     Serious concerns about downwind work.

Luff Pocket with Boom: Moderate weight, Easy to handle
     See example below.

Sail track with Wishbone: Moderate:weight, Easy to handle
     This is the default, performance wise should be nothing to complain about.($$$$)

Poking around the internet I found this rig combination from Schionning Designs of Australia. I'm showing this one first because you can really see the shape of the boom.

In this picture you can see a luff pocket version carrying a reef on both sides.

In other pictures its pretty obvious that the main is carried loose footed. It also looks like the mast is fixed and the boom is on a gooseneck.  I'm going to do some more research to see if I can figure out if that is true. If my boom can go high enough not to hit me in the head then this may be a possibility. You get the aero efficiency of a luff pocketed sail, downwind you have a boom to work with, and you avoid sail-tracks. Note the absence of a vang. I wonder if the boom is rigidly attached (vertically)? 

Alaskan Yellow Cedar Spars glued to Rudder Faces

I have daylight in my favor so I glued my AYC to two of the rudder faces. Once this cures, (and my ordered materials arrive) I'll be ready to start assembling the rudder on the jig.  Probably can't tell here but I wrapped the end clamps in cellophane to make sure I don't glue the rudder to the clamps.

I have tried, by hand, to bend the plywood along the short side as is required when forming the rudder. It is no easy task. So I have an idea to help clamp these closed on the jig in a "halfway" position to make it easier to install the carbon fiber. I'm go to do a little trig and figure out how wide to make some sticks that will work with the jig.  Picture roughly a 2x4 with one edge cut off at a 33 degree angle. This can then be slid between the angled jig faces and the rudder faces. Here is a little sketch to help.

The red arrows show where a down force could be applied using clamps.  The hope is that with the clamps holding the rudder in a compressed position I will be able to concentrate on getting the carbon fiber installed and wetted out.  I will need to get another pair of the longer reach clamps to do this, and will need some more clamps for closing the rudder as well. Composite brads are of no use here.

Notes on AYC

Since this project is going to take me forever to complete, I have to focus on the little things I'm learning along the way. I milled my Alaskan Yellow Cedar today into 20mm spars for the inside of the rudders.
I knew that AYC has a reputation for being toxic when cut. So I used gloves and my respirator while I had sawdust flying around. I did some more research and it looks like it is an irritant that affects some more than others. I used my gear and vacuumed up the dust and haven't felt any ill effects.  This wood is very soft, it cuts easy and sands down very well. I would say it is about like working with poplar.  I ran out of light early so next trip to the hardware store will see me buying some stand lights. I didn't epoxy the spars to one face of the rudder because I didn't want to do it in the dark and in a rush. Besides I'm still waiting for my micro balloons and carbon fiber to arrive.
 

Getting dark early in Seattle.

Taper Cut On Rudder Faces

I took plenty of pictures to support a detailed post. The faces of the rudders are made of 4mm Okume. Where the faces close at the trailing edge, a tapered cut has to be made so there can be some contact surface between the faces for a solidly glued joint.  I have a hand planer. In order to get an angled cut from the planer, I build a jig. The first thing was to make small 8 degree wedges, I did this on the miter saw. I clamped on a stop for the stock to insure that all the wedges came out at the same thickness.

Next I brad nailed the wedges to a piece of 1x2 strip. I used the polymer brads so I could go through these later with screws and not worry about getting tangled up in metal brads.

Next I screwed this strip with the wedges into the side of a 2x4. Basically giving my planer guide something to slide against that is set up at the right angle.

Here is a profile view. Some the wedges protruded a a bit so I sanded that off.

I set up the rudder face blank as shown. Couple of notes, I cut the blanks extra wide that way if anything untoward happened I could have another try. Also learned that everything needs to be thoroughly clamped in place. I tried to get away with omitting some clamps and things started moving.

Here is the profile view

I took three passes at 1/32 depth setting to get it right. Technically it should have taken 4 passes not sure why but three seemed to do the trick.

Here is the profile

I set these up on edge just to show how they came together.

This was my first time using a power planer and I could really tell the difference in the quality of my cuts as I got used to (and learned to trust) the tool.  It's a fun tool to use, its powerful but not hard to control. The hardest part was keeping the power cord from hanging up on stuff. I gave up on connecting the vacuum hose since it got in the way too much. I still need to cut these down to proper width and mill my piece of alaskan yellow cedar into spars for the spine of the rudders. Then it will be time to start putting things together on the jig.

Spending Sleep Time Thinking About Rig Options.......again

I figured that since I spend a considerable portion of my life thinking about this it warranted its own post.

Here is the problem. The Duo 660 is set up for unstayed, rotating, carbon masts. But I want to be able to throw out the sail for downwind sailing, so I need a boom.
    Puget sound wind is often out of the North. Puget sound is mostly a North-South body of water, so
    usually you are beating to the wind or on a run.

The conventional answer is to use wishbone booms.
     Then I lose most of the benefit of rotating masts (can't be used to furl or reef).
     Also need to install sail track: risky or expensive on carbon masts
     This is my fall back position if nothing better comes along

Freedom yachts used rigs that used sails that wrap around the masts (read no sail tracks) but still had wishbone booms. I think they must have used topping lifts but cant quite figure out how they rigged the snotter, or why the wishbone wouldn't just bang into the mast. Not to mention reefing.

I hate (I should stay dislike) the Bermuda rig. The presence of the boom vang and topping lifts give away the issue here. I suppose its feature is that you have controls (of various levels of effectiveness) to influence all areas of sail shape. The bug is that you have to use all those controls. Besides I don't think it a good option for an unstayed masts.

I thought about trying to design a 3-D wishbone that could freely rotate about the base of the mast but curve up and around the sail to engage the sail clew like a conventional wishbone. But this entails some complex and likely heavy bearing hardware. And I'm not sure I could ever trim this right in a breeze since the downforce on the leech would likely be limited to the weight of the boom (which I would be trying to keep light). A regular wishbone accomplishes this by pushing off the mast.

My latest thought is to use softwing sails, perhaps junk rigged?.  This is sexy, but not sure if it would be too heavy. And I still lose the rotating masts, but wouldn't have to deal with sail tracks. Of course there is expense to consider as well. The idea would be that no boom would be required because of the battens. But then how to reef?

You can see why this leads to sleeplessness.

Rudder Jig

This is was my last opportunity to work on the boat until next week and things went as well as could have been expected.  I was worried that I was going to chase my tail trying to get the rudder jig base level in both directions. Fortunately I got there using just one shim.

Cutting all the Jig frames did get tedious but I have to put in a shout out to Makita for their track saw. I used melamine covered particle board for the frames and the edges I cut looked better than the ones that came with the material.

Kind of fits into a larger theme that I learn and re-learn, Using the right tool makes a huge difference, both to the outcome achieved and the amount of frustration felt on the way.  Below is the picture of the finished jig.

It will be a few days before I can get back out to the shop. I am planning on doing some detailed posts on the planning and execution of the "feathering" cut that is needed at the close of the rudder faces (still mulling over how to do this).

Rudder Set Up, A Dry Run For The AMA

I've been out of it for awhile, my wife was sick and then the entire family (including me!) got sick. Which also means my sons birthday party got postponed, which means I'm kicked out of my boat shed for another week.

With that off my chest, I did weasel in a way for me to keep working on my boat. My boat shed is 8 X 24 ft (I love it when I can talk imperial units). My son's party can get by fine with 16 of those feet. So I started setting up rudder construction in the back of the shed.

Here is the rub. My shed is set up in our driveway, our gravel, on an incline, driveway. So my plan for the amas was to pour small concrete footers that I could make level and then set up level lumber "rails" as a base on which to set up the ama build. Since I can't build the rudders in the garage (see previous post) I will set up the rudder jig the way I was thinking of setting up the ama. A little practice won't hurt.

I used 4" PVC pipe fittings for forms, and set them up level as shown.

Then I poured in the concrete and set in joist hangers to hold the 2x4s I plan to used a base to work from.

The two in the foreground will need to go away when its time for the ama. But this way I  can try out my plan before its time to do footers for the ama, and I get to keep working while waiting for my son's birthday party. I just poured the concrete today, I need to give it a day or so to cure.....