Kris wrote:

Scott,

I scroll back thru the conversation to the info regarding a lamp post. Does your post has an inspection door in the lower part? What you going to do about, if so? This is my case and I am not certain how to deal with it.

Hi Kris,

Your profile says that you are building one of Jerome Delaunay's designs. I like how his boats look as drawings. I hope you will share some build photos. The center cockpit scow with two masts looks especially interesting.

The short answer is that my lamp post does not have an inspection door.

The long answer is that I was able to avoid the issue with the inspection door after some persistence. The first two vendors I contacted stopped talking to me as soon as they found out I wanted to use the the lamp pole as a mast.

I tried to keep quiet about my intentions with a third vendor but eventually he told me that they can't sell a lamp pole without an inspection door. The inspection door is required by the NEC (National Electrical Code). I imagine that there are similar regulations in the EU.

However this third vendor was very happy to sell me a pole without a hand hole after I told him that I would not be using it for a lighting application. I had to sign several documents but in the end I was able to purchase a plain tapered 6063-T6 pole without any holes.

I remember seeing photos from at least one JRA member who purchased the pole longer than necessary and then cut off the lower section with the inspection door. If I remember correctly the mast on Ming Ming II was made this way.

Please understand that I have not yet built a functional junk rig with this pole. The most I have done is get the mast vertical in the tabernacle. I am not any sort of an expert or authority. With that said I think you have a few options.

1. If the pole is long enough cut off the lower section

2. Cut off the lower section and extend the upper section with wood or an alloy tube

2. Get a different pole

3. Add a sleeve inside the lower section or on the outside of the lower section

4. Determine, somehow, that the pole is strong enough with inspection door installed normally.

David Th wrote:

Scott wrote:

Looking back at my notes this is what I picked out for aluminum battens after some discussion here on the forums and over email.

1" OD X .065" WALL (.870" ID) 6061-T6

This is 25.4mm Outside Diameter and 22.1mm Inside Diameter. It is only a hair bigger than the smallest, 25mm, that you recommended.

Do you think it is reasonable to expect these dimensions to be stiff and strong enough?

Well, I am no expert on this, David Tyler is the man for that. 

David Th wrote:The alloy battens were the top three on the sail and were 6.5 meters in length and from memory about 65 mm diameter and 1.5 mm wall thickness. To lift them individually there was no flexing, and with the sail up and working there was very little deflection, not really noticeable at all. I know the recommendation is to use T6 alloy which would allow smaller diameter but my T5 battens were fine. I imagine for your sail you would only need 25 to 30 mm diameter battens, but others might be able to advise better on sizing.

Thanks for the response, David.

In hindsight it seems like going with aluminum would have been easier to get right, given what I have learned about fiber orientation in pultruded tubes. Not all fiberglass is the same!

Looking back at my notes this is what I picked out for aluminum battens after some discussion here on the forums and over email.

1" OD X .065" WALL (.870" ID) 6061-T6

This is 25.4mm Outside Diameter and 22.1mm Inside Diameter. It is only a hair bigger than the smallest, 25mm, that you recommended.

Do you think it is reasonable to expect these dimensions to be stiff and strong enough?

This reminds me of when Annie was looking for battens for Fanshi, and the pultruded stock tubing readily available in NZ was found to be too floppy to support its own weight, like this USA stock. This must have been made with random directional fibres as well.

David Th wrote:

Would you be better off with aluminium battens? I used T5 alloy battens very successfully on the big sail on Footprints. They were light but strong and I never had a failure. Larger diameter with thinner wall thickness seems to produce a reliable batten. But it looks as if you are locked into a diameter based on your already made batten pockets. 

After reading the other David's message I spent part evening trying to find unidirectional fiberglass tubes. The only ones I can find online are VERY expensive. The remainder of my evening I have been convincing myself that ripping out the batten pockets and replacing them with larger ones might be fun. I think I have all the materials for that effort. At least I do not need to buy anything.

It is a real bummer to waste all the tubes and epoxy that I put together only a few days ago.

I don't know how you can quantify this but can you give me some idea how rigid the battens were on footprints?