Trawl Doors Before Trawl Doors

Before trawl doors there were, well, no trawl doors. History tells us that commercial fishing went kind of from the beam trawl to otter trawl. That’s not to say that all the other methods aren’t important, but my focus – being pelagic – does have trawl doors as the keystone in the whole arrangement. So trawl doors is what I have to look at. If you’ve perused some of my previous posts, you couldn’t be blamed for thinking I have trawl doors on the brain. this, of course, is my excuse for bringing you three more examples from the archive. These three represent something different, though. These three are all early attempts to keep the mouth of a trawl open without beams – and without doors.

The earliest patent is GB189730188, dating from 1897. Here, messers Lewis Levi and George Cartwright, Brass Finisher and Hotel Keeper respectively and both of Hull, clearly think otter boards are a waste of time. Their intention is to do away with both beams and otter boards, by way of a a watertight tube that runs around the mouth of the trawl. The idea is that by using “hydraulic pressure, air pressure or the like” to inflate this tube with either air or a liquid the mouth of the net stays open. What the patent doesn’t explain particularly well is how this is meant to be weighted or protected from the rigours of the seabed…

GB189730188 - the hydraulic tube mouth opener...


One patent that bemused me no end is this one: US649581, dating to 1900. An American patent, this one appears to be a rigid frame, which will hold the mouth of the net open. The inventor, John G Landman, a resident of Brooklyn, New York, states that the purpose of his invention is the “provision of a simple, cheap and effective spreading-frame”. His object, as such, is economy and simplicity.

US649581, the net-spreading frame from Brooklyn, New York

Last but not least, I find myself gazing at a British patent whose applicant hails from Japan: GB102554. Dating to 1916, this patent professes that it “relates to otter boards and the like for steam trawling apparatus of the type where the rear ends of the otter boards or the like are attached to the head and foot ropes of the trawler net….” I would quote more, but the rest of the sentence runs on for another paragraph or so. The long and the short of it is that the otter board is not a board but an arrangement of canvas covered ‘ribs’.

GB102554, the alternative otter board, comprising mainly of canvas and 'ribs' of metal.

What caught my eye was the name and nationality of the inventor – “Tsunejiro Shirato, of Misakino-machi, City of Shimonoseki, Empire of Japan, Engineer…” Certainly not the phrasing we would expect in more modern, PC-stricken documents. But it’s certainly interesting to consider what and why Shirato felt the need to patent his invention all the way in Britain, why he didn’t do so in the USA and the research/experimentation that he conducted that resulted in his belief in his invention.

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