Ships masts

On holiday in Australia, visited the Sydney maritime museum and in particular, the James Craig - 1874 3 masted sailing barque. Built by Bartram Haswell & Co Sunderland.
Question, the mast and main spars are hollow steel plate, hot riveted from rolled steel sections. They have 2 semi circular halves lapped and riveted together and to get the length are also made of overlapping sections along their length. The mast diameter is too small to get inside, so how did they get a "dolly" inside. Each section is probably 12 feet long.
BobH

I would think it would be an extension of the pipe riveting industry

Edited By Ady1 on 17/01/2018 09:38:26

Ah, so they didn't just rivet an expendable child into the assembly...

Whatever technique was used, it (unfortunately for us) seems to be too commonplace for the Chief Constructor to mention it in the chapter on iron masts in "Shipbuilding in Iron and Steel" (from page 259 & table 7 on page 522) **LINK**.

Hard to imagine that any kind of dolly or hydraulic rivet press could be inserted from the end to the full length of a section, especially if there was internal bracing as described in the book. Perhaps the back of the mast was supported so that a jam back could be used to snap the rivet?

Brian

Fascinating stuff Ady1. It could well have been that process, putting the hot rivets in from the outside. The rivet heads that I saw were very flat and I had assumed that the head was inside the mast, but I wonder if they were "un-headed rivets" that were made from hot bar, heated on the coil of rod, stuck in the hole, chopped to length and then swaged.

On a similar matter, the Dublin 'spike' was erected by a man tightening the bolts from the inside, all the way up. According to the architects' website.

Geoff

It makes you realise how clever trees are, even it they go slowly...