Jacobs Schupert "sectional" firebox.

What do you guys know about these.

Jacobs-Shupert United States Firebox Company

here is a link to the test of a staybolt firebox and one of the Jacob Shupert versions; http://books.google.com/books?id=d39MAA ... ox&f=false

It was a firebox design that did away with staybolts, but was prone to corrosion at the seams (at least on coal fired boilers) and leaks. The Santa Fe experimented with them as part of their Mallet locomotive experiments.

http://www.steamlocomotive.com/2-6-6-2/?page=atsf

Others experimented with them as well; but it was never widely adopted.

With plasma, laser and all the other sheet metal cutting processes and the incredible welders we have available today, maybe its economics, and its time have arrived.

If it offers a larger margin of safety, that reduces insurance rates.

It might also reduce boiler mntc. costs significantly.

My memory tells me that another problem with this firebox design was that it was not easy to repair; I believe you had to take it completely apart and rebuild it instead of just replacing stays or patching like a conventional firebox.

The owners of these must have been betting on no internal mntc. for long periods of time to make these economical.

It might be difficult to inspect, unless you used a scope. Then when you found damage you would have to cut the thing apart to get to it.

What if in service you could get 20 years out of a J-S firebox and have no internal issues, I suppose the question is then: What are the annual costs of stay bolt replacements in a traditional firebox, and is that cheaper than no stay bolt issues, and a J-S firebox replacement for a 20 year period.