Saturday, January 16, 2010

Sail Design and Building, Version I

In no time, I had the basic hull done and ready to flip over onto its trailer, where it would ride until launch day. A crew of friends came down to help me with the roll-over, and It seemed like the end was almost in sight. Then things slowed way, way down.

Maybe a lot of first-time boat builders discover that the sail rig of a boat takes a long time to put together. It was worse, because I was designing mine from scratch and sewing the sails. Moreover, I wanted an adjustable system of steps and partners, three of each as I will explain. And as I was to learn, when you modify any small element of boat's design, it can have ramifications from end to end. It gave me a deep appreciation for Phil Bolger's work to be an amateur at it.

So, if I think so highly of Phil's art, why mess with it? As I mentioned before, experimentation was my goal before I even chose a design. But I have to admit I was not fond of either of Birdwatcher's designed rigs on paper. Phil Bolger told me of a fellow not far from me who had built a Birdwatcher, Aeneas Precht. His boat is gorgeous, radically customized and built of Airex. (If anyone has a link to the pictures of it that used to be online, please send.) Anyway, Aeneas told me the Bolger solent rig was very unwieldy to handle, did not set as well as he liked. As for the smaller leg o'mutton rig, it was by all accounts too little canvas for the light airs you experience lake sailing. 

Historically, most sharpies had two sprit sails in a cat-ketch configuration. "Reefing" was done by taking down one of the masts and moving the remaining one to a middle position. It seemed like a good starting point. And for me it was a way of exploring a bit of history.

I set about drawing the rig and went through many iterations. I looked at the sharpies in Reuel Parker's Sharpie Book, looked at the many boats in the books of Howard Chapelle, of Francis Herreshoff. I eventually settled on four-sided sprit sails with sprit booms. Bolger describes many advantages to this rig in his hard-to-find 103 Small Boat Rigs — short spars, low stress, good windward ability for a low-tech rig. To balance the sails properly, I simply positioned their combined centre of effort in the same position Phil Bolger had placed his centre of effort. If my centre of effort was off, I had the movable mast steps to provide some adjustment leeway.

The sail rig you see in the title photo of this blog, and the picture above, is pretty close to that first design. 

For the masts I used grown trees about four inches in diameter at the base, fire-killed spruce from a burn up north. The trees were die-straight, branchless and barkless yet still standing three years after the fire. They say air drying makes for strong lumber. These were strong enough to stand on without breaking. To prepare them, I just pared them a little with a draw knife, then oiled them. Their natural irregularities are all but invisible, and the time saving over built up masts was enormous. As for hollow masts, there is not much weight savings on spars at this small size. I also used trees for the peak sprits, though these are a bit too heavy and I will make some lighter spars when I can. I love the low-technology. When I sail in remote areas, I bring an axe, saw, draw knife and hand drill, comfortable in the knowledge that I could replace an entire mast in not much time just by going into the bush and taking a tree.

I mentioned adjustable mast-steps and partners, and having three sets of each to accommodate having either one or both sails in play. For the partners, I just made mine out of wood. To make their position adjustable, I have them sliding on a kind of wooden rail attached to the coaming. The mast step also slides on a rail. The partners are wide open on one side, and the masts are held in place by 2-inch cargo straps. The straps attach to a cheap, galvanized kind of cargo tie-down track.

All this is easier to see in a picture, looking down:

And here is a shot with the rig stowed, where you can see the mast partners more clearly:

The cargo strap and track idea was intended to be temporary, to aid in the experimentation phase. But it is immensely strong, dirt cheap and very easy to use. The wide straps and partners do no damage to the mast. The track serves as a kind of toe rail, and it is very handy to be able to attach a ring at any position along its length — for jib sheet blocks, dock lines, etc. I can't imagine doing without it now.

The sails themselves I ordered ready-to-sew from a good American company called Sailrite. They deliver computer-cut panels that only need to be stitched up. I had some slight experience sewing heavy fabrics, so decided to tackle this job. Many people just hire a sail loft to build them sails, having no taste for sewing. (If that describes you, then you can either skip to the next post, or just read on and find out how the other half lives.) 

Sail-shaping is an art; mere sail-sewing is not too difficult, but information on doing it is hard to find. The testimonials I read on the otherwise excellent Sailrite website all seemed to be from people who had sewn a lot before, and they didn't address the realities of struggling with a home sewing machine. I want to stick to Birdwatchwer-specific information on this blog, but I will digress into some how-to in this case.

From a skills standpoint, the techniques you use on a sail are very straightforward, much more rudimentary than making clothes. Even if you have never touched a sewing machine before, you will manage fine if you get someone to show you the basics of a simple stitch, and then practice some runs on scrap pieces. 

The ideal sailmaking equipment is a walking-foot, commercial sewing machine surrounded by 200 square feet of table or more, and maybe an apprentice you can order about. But you can manage with humbler arrangements. We had an old Singer, but it didn't do zig zag, which you need. So I took some of my scrap sail cloth and went to a repair guy who also sold machines. I told him my purpose and asked him to find me the sturdiest home machine possible. He said almost any heavy older machine with a sharp needle will pierce many layers of heavy material. The trick is finding one that will keep tension on the thread. He sold me a 1960s Kenmore that weighs as much as a small anvil. He wanted $40 for it, but — since it came with good advice about dealing with heavy fabric, a demo using my scrap, and a story about his sister that was both funny and sad — I made him take $60. My guru showed me how to wind the thread around the thread tensioner twice, and really tighten down the bobbin screw. You will certainly have to feed the slippery polyester sail cloth by hand because the feed dogs of a typical machine cannot get a grip — but that isn't hard after a small bit of practice. 

A portable machine can be set on any flat surface, and working on the floor would seem sensible. But then you are in the wrong position to use the little go-pedal, and it just kills the lower back. To work sitting up, you will need to jury-rig a collection of tables to hold your sail as it grows. An arrangement similar to the infeed and outfeed tables you see around table saws is what you want. Once you are set up to work, you can complete the machine sewing on a fairly large sail in a day. There is usually some handwork to finish the sail, and you often need spur grommets in the corners. Setting spur grommets requires a special tool. I just take my finished sails to a tarpaulin place and have them set grommets for me. I have now made, repaired or altered quite a number of sails, each time wishing I had the right equipment and work space. Somehow, the pleasures outweigh the troubles for me, but only just. 


  1. Thanks for the great posts. I have an almost finished Zenith 601HD airplane in my garage but my eyes are wandering toward building a Bolger boat for the same reason you cited in your first post. I'm not sure I'm sold on the birdwatcher looks, but I do like the innovation. I hope you continue with the posts - I look forward to reading them.



  2. David:

    Thanks for reading and commenting. It makes me feel like the posts are of some use. I know your aircraft type, a well-proven design choice.

  3. I had the pics of Aeneas boat at my geocities site which has since shutdown. I'll have to dig them up and repost them somewhere. The link was here:

    my email is the middle portion at