Acetylene Gas Used To Straighten Ships' Decks

Sunderland Shipbuilders, part of British Shipbuilders, is using a new system of heat treatment to straighten the decks of ships.

The technique, known as "flame straightening," uses dissolved acetylene gas in a specially developed blowpipe.

When a ship's deck is being constructed, stiffeners are positioned under the deck panels at spaces of between 700 and 800 millimeters. In between the stiffeners, ripples occur which can be as much as 25 millimeters deep.

Previously, straightening was achieved by positioning 76 millimeter flats underneath the deck, which was an expensive and timeconsuming method. It is in the shipbuilder's interest to straighten some decks, as subcontractors applying covering compositions charge more if ripples are excessive.

Using the flame-straightening technique, Sunderland Shipbuilders has reduced the ripples to five millimeters variance with an average of two heat cycles. For particularly bad areas, three or four cycles may be necessary.

Panels are first checked using a straight edge, and then are heat treated using the gas in specially developed plate straightener blowpipes blowpipes.

Decks treated to date have a plating thickness of between eight and 12 millimeters.

Flame straightening has two significant advantages over previous techniques. These are a faster and more efficient operation with the multi-nozzle blowpipe, and the fact that the principles of application are easily learned by the average workman.

The method is now being used F L O R I D A — J a c k s o n v i l l e W e e d o n Engineering Co., Inc.

G E O R G I A — S a v a n n a h Southern M a r i n e S u p p l y Co., Inc.

L O U I S I A N A — N e w Orleans H u b e v o M a r i n e Plastics, of N e w Orleans, Inc.

M A I N E — P o r t l a n d Chase, Leavitt & Co., Inc.

M A R Y L A N D — B a l t i m o r e Tate Temco, Inc.

N E W JERSEY—Linden Beacon Packing & Equipment Co., td.

O R E G O N —Portland American-Pacific Corp.

P E N N S Y L V A N I A — P h i l a d e l p h i a 3 P h i l a d e l p h i a Ship Maintenance Co., Inc. — S O U T H C A R O L I N A — C h a r l e s t o n Southeastern Supply Co., Inc.

T E X A S - H o u s t o n Texas M a r i n e & Industrial Supply Co.

W A S H I N G T O N — S e a t t l e M a y & Smith Company B E L G I U M — A n t w e r p V e r f a i l l i e & Elsig SPRL C A N A D A — H a l i f a x H u b e v o M a r i n e Plastics, Halifax F L O R I D A — M i a m i Seastores W h o l e s a l e Co.

by Sunderland Shipbuilders at each of its three yards in northeast England, and additional blowpipes are on order. At present, the accommodation decks only are treated in this way, but there is a possibility that hulls will also be treated by the same method.

Ships currently being treated are dry cargo vessels for the Bank Line of London, and bulk carriers for Yugoslavian owners.

n Avenue Phone:: DISTRIBUTORS o i n e d o p p l i c a The flame-straightening operation takes a man on average one week per ship.

The company has been using the system for six months, and group welding engineer Don Cuthbert reports that it is "the best method we have used to date." The process was developed by British Oxygen Company (BOC) in collaboration with Sunderland Shipbuilders.

Other stories from August 1978 issue


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