Al Sorenson's bilding technique

[MarkC]

Ken Hankinson used to run a web-site that featured quite a few interesting boats. Alas he has retired - the site is no more, and there has been no word on further supply of plans. My fault - if I had just bought the plans I wanted.

One section of this site was devoted to small Tugboats plans and featured metal-boat-bilder Al Sorenson and his technique of very-light steel boat building - using 'tempering' I believe for fairing (or strength??).

From my memory it looked like 'longitudinal stringers' in the form of flat-bar on a jig, with thin steel-plate welded/attached to these stringers, then this plate heated in 'spots' - I cant remember if it was one, two or three 'tempering spots' per plate.

I have seen 'similar' spots on other, much larger steel boats under construction - also 'tempering'?

Question: Was this process used by Al Sorensen and featured on Ken's web-site really novel - or is it something that most steel-boat manufacturers have a good handle on?

Was there a book/info pamphlet offered by ken that outlined this process?

In effect, this process looked interesting and I would like to keep it circulating here for interest sake - and for my information too!

[kmorin]

I believe Boatbuilder magazine had a series of articles by K Hankinsen that showed a small steel tug in build and described this technique about four years ago. (not sure of dates of issues)

Cheers
kmorin

[CDBarry]

The article was by Mike Kasten, who has a website.

The technique of heating is called "line heating". Google it.

[MarkC]

Thanks for the answers and the info -

googled up 'line heating' - one site from MIT Ocean Fabrication Division or so.

'line heating for forming flat-plate into three-dimentional forms - used in boat building for 30 years - very much a 'hands-on' process, experience etc.'

Not much more info that I could find. Maybe I missed something - but I did spend some time.

I read Kasten's articles:

(an excellent PDF - a Metal boat society quarterly about all metals) - found a very little on tempering and annealing.)

I didnt find anything on line heating or Al Sorensen.

I will email 'boatbilder' and ask for the correct copy.

and short of disturbing Kasten Marine with an email - is there anything else?