by William Lafferty » November 29, 2017, 11:49 am
Here's what hayhugh2 (first paragraph) and I (second) wrote about this subject in 2010 on this board:
Telescopic hatches with 12 foot centers were utilized on the self-unloaders so as to fill up each hatch for more tonnage. one piece hatches needed space between hatches for stowage. Not an issue on ore boats, but boats in the stone and coal trade used all available space and would still not put her down to her marks.
The commonality here is that newbuild self-unloaders after 1938 had telescoping hatches, probably since the unloading booms and hatch cranes as then utilized were thought to be incompatible for clearance reasons. The first new self-unloader I can think of with a hatch crane was the Cape Breton Miner. Early conversions of vessels with single-piece hatch covers, beginning with the E. B. Barber, John T. Hutchinson, and Hochelaga the year the Cape Breton Miner was built, 1964, retain the hatch cranes and, probably, original hatch covers. I do find it odd that a vessel like the Adam E. Cornelius did not have one-piece covers and a crane. I wonder if the switch from flat to tubular trusswork for the unloading boom resulted in more clearance for the crane.
Here's what hayhugh2 (first paragraph) and I (second) wrote about this subject in 2010 on this board:
Telescopic hatches with 12 foot centers were utilized on the self-unloaders so as to fill up each hatch for more tonnage. one piece hatches needed space between hatches for stowage. Not an issue on ore boats, but boats in the stone and coal trade used all available space and would still not put her down to her marks.
The commonality here is that newbuild self-unloaders after 1938 had telescoping hatches, probably since the unloading booms and hatch cranes as then utilized were thought to be incompatible for clearance reasons. The first new self-unloader I can think of with a hatch crane was the Cape Breton Miner. Early conversions of vessels with single-piece hatch covers, beginning with the E. B. Barber, John T. Hutchinson, and Hochelaga the year the Cape Breton Miner was built, 1964, retain the hatch cranes and, probably, original hatch covers. I do find it odd that a vessel like the Adam E. Cornelius did not have one-piece covers and a crane. I wonder if the switch from flat to tubular trusswork for the unloading boom resulted in more clearance for the crane.