JEM Watercraft

Hello morten,

I have not emailed for a long time, but the building of my norweigan pram is coming along nicely. She is right way up, with the bottom glassed and Im currently working on my re designed interior. Hope fully the boat will be ready to get wet for my birthday in march.

I am considering using an un stayed lugsail instead of the designed fore and aft rig. Because I cant find any suitable wood for building a mast, I have been doing a little research on aluminium tube sections. I have found a tube section with an outside diameter of 76mm and wall thickness of 5mm, at a reasonable cost. Its not from a "marine" shop, so they couldn't really give an informed opinion of weather or not it would be suitable for mast. all they could say is that it is structural quality(?).

Do you think aluminium is suitable for unstayed masts? Or would it be to weak/flexible?

I guess I could always try without stays, then add them later if things dont work out.

Thanks again, the shape of the hull is beautiful.
Brendan Porrill,
Brisbane, Aus.

Hello Brendan,

That's great news. I am very glad to hear the boat is coming along fine.

Sure you can use an aluminum mast for the boat. At first it looks all right with the dimensions you have found, but to be sure it will be best to make some calculations. That will show for sure. Could you please give me some details about the lugsail you have in mind (sail area and mast height) and I will run the calculations to see if the tube will be good enough.

I am not sure what they mean by structural quality, but if it is a quality meant for staging or other constructions I would not have any doubt using it.