Hi All, after sailing my junk-rigged schooner for a couple of years along the south coast of France I have realised I have to do something about improving the handling of the rig, among other things I need to lighten the sails and/or reduce the friction of the running rigging. To that end I've replied on this thread because I am interested in going over to bamboo battens, principally because I live in France and the cost of aluminium will be prohibitive.

I have the original Hassler rig with flat cut sails and what appear to be ash battens. The yard dimensions seem to have been taken straight out of Practical Junk Rig and are well made, as is everything on the boat. My questions at the moment are: how to begin calculating the diameter of bamboo needed for the size of my sails, is there really a noticeable weight saving over ash and does anyone have advice on the various species of bamboo? I am in contact with the bamboo association here and they seem keen to help find a supplier (someone on here mentioned one near Toulouse, which itself is only one hour from my house).

Left to my own devices I would do what I did when offered some GRP tubes to replace a couple of broken battens. I placed one of my battens on two supports, one at each end, and hung a known weight in the centre, measuring the deflection. Then I did the same with the GRP tubes and they were a bit stiffer. They were also free so I used them in the top panels. I could do this again, but I would like an idea of what I was looking for in the deflection.

Any ideas and suggestions gratefully received.

 

Anonymous wrote:

I am planning to use bamboo for the battens on SibLim.  There are many reason for this, including cost, the use of even more of the earth's resources, having managed to  bend T6 alloy battens and the fact that bamboos grow (literally) like weeds in New Zealand.  David and Lynda's article about preparing their bamboos for Tin Hau has given me one route to follow, but I would be interested in hearing of other people's experiences, preparation, choice of bamboo, etc.  And how long they last!

I had bamboo battens on Pip, SA=20m2, and carried a few spares on deck, but I never broke one. They were untreated and stitched on while fairly green, but not fresh cut. Before the bamboo I had wood, which was oversize, too heavy and too stiff. The sheet blocks were attached to the leech end by drilling a 4mm hole in one side and threading braided nylon through that and tying it off around the last joint in the bamboo.  I used nylon for the attachment, threaded through pairs of holes burned through the sail with a hotwire. 

Fair warning about the bamboo- if you have aluminum masts they will squeak enough to be annoying on a very quiet day. However the bamboo and aluminum coexist happily, neither one wearing the other. The aluminum yards are a different story. Contrary to Colvin's claim that they don't wear, the yards and masts were wearing serious grooves in each other. Corrected with strips of a plastic cutting board found on a beach screwed to the yards.

The battens on Nomad have always been bamboo since that was what Tom  Colvin had recommended as being the best material after testing a variety of others. Bamboo has other redeeming qualities from a cruisers standpoint. It can be had free or very cheaply for the effort of going into a stand of bamboo and cutting some appropriate sized pieces and dragging them back to the boat. The spares that you should carry do double duty holding up sunshades, poling out the jib and even outriggers for towing more than one fishing line. 

Bamboo battens are cut at a joint at the forward end and the aft end is cut flush with the leach. There are no batten pockets. There are grommets at every seam and a cable tie is threaded through sandwiching the sail between the bamboo and backing batten. This adds a little strength and prevents the sail from wearing at the battens when it's up against the rigging. My backing battens were ripped out of a pressure treated 2x6 and scarfed together for the longest pieces. Like the bamboo, no maintenance required.

As they age sometimes they split. This is not usually a problem unless it extends through several joints. When this happens, the bamboo can be held together with wire seizing or cable ties without being removed from the sail. If reinforcement is needed, pieces of split bamboo can be added easily. Or just cut a short length of bamboo reaching several grommets past the damaged area and cable tie it in place . I have a few like that now, it's working well enough that I don't see any need to change it until it gets replaced. 

The bamboo battens have never broken in normal sailing even in some quite stormy weather. All the battens I have broken including three last month ( first time in a couple of years) have been from unplanned gybes. Sometimes the bamboo splits where the padeyes for the lazy jacks are screwed in or where the bamboo and backing batten is through bolted at the aft end of the sail. All bamboo is not created equal. Some has much thicker walls and it holds up  better and is less prone to splitting. I don't know how to find this out without cutting down a.piece to examine it. Of course if you need some, whatever is available will work. I have bamboo from three continents in the sails at this time, not all of it the thick walled variety and it all works well although the thinner ones split easily.

No special preparation is needed before use. Take a chisel and smooth the knobs where the branches were, the sails and your skin will appreciate it. Green bamboo will make the sail quite heavy to hoist but they will dry out and become much lighter within a month or so. Towing them back to the boat behind the dinghy gets rid of most of the bugs. If you get a local boat to deliver them to you, beware of rats hiding inside the bamboo, much better to bring them home yourself!

On Lakatao, we have always used bamboos.
The first ones came from Brittany and dried in the shade of a shed stored horizontally, suspended in the air and in bundles so that they remained as straight as possible.

We left them natural, with leather as protection in contact with the masts. The yard and the boom were also made of bamboo.
During our first two-year trip to the Atlantic, we kept breaking battens and cutting bamboo in almost every country we visited.
For the second set of sails we used bamboos that were growing in our garden (still in Brittany!) but we chose them a little smaller in diameter and covered with a sock in glass fabric and epoxy resin.

We have had them for eight years now. We had to break two or three of them, but we repaired them with an inner sleeve and the same epoxy glass cloth process. The protection is provided by pieces of yellow 32 mm diameter garden hose open and held in place with  lacing and   plastic collars. There is a little pocket on the leech side only, battens are lashed on the sails trough eyelets.

We had some tears aroud these eyelets and now we want to use webbing loops for the lashing.

The yards and booms are now made of wood according to the specifications of Pratical Junk Rig.