Patent Timeline – So Far…

After a fair few weeks wading through some patents, I have whittled them down to the relevant few. These are the backbone of my timeline, which will be filled in along with other documentation and whatnot. I’ve only gone up to 1959, as after that it gets a bit more convoluted and would make this entry twice as long!

The initials in brackets after the name indicates the applicant’s nationality, while the brackets after each entry have the patent number. The letters there are the country in which the patent was made. The dates are those in which the patent applications were made, not in which they were granted (anything up to 5 years after the application).

Adam GB189420323 Patent


Oct 1894 – William Adam (GB) patents a 3 boat pelagic trawl. It’s all a bit odd, but he is thinking outside the box and trying to make a functioning mid-water trawl. [GB189420323]

Nov 1898 – The first patented vertical trawl door by David Sherrit (GB). It is, however, entirely a demersal affair. But like William Adam, the idea and willingness to experiment a bit are there. [GB189824035]

Nov 1922 – Cornelis Pieter Dros (NL) patents what looks lake a trawl that can vary its depth. It is, however, not a pelagic trawl in the true sense, as the impetus for this design lies in engine and fuel efficiency, not in optimising the catch or range of the ship. [GB202887]

1925 to 1935ish – V D Ltd, a company comprising of two Frenchmen, Oscar Dahl and Jean-Baptiste Vigneron (and later on, William Black) make a series of patents for demersal trawls. The innovation here is the idea of not connecting the net directly to the trawl doors. After 1940, almost all pelagic trawl patents distance the trawl doors from the net with cables of some description.

Sep 1930 – Unlike Cornelis Dros, this patent by Marcel Simonin (FR) is specifically designed to be used at whatever depth is desired. The design is quite simple and has a very narrow mouth with the net being directly connected to the horizontal trawl doors. [GB356493]

Dec 1938 – Franz Suberkrub, along with Ernst Karl Ludwig Roscher and Kurt Jaeger Hansing (all DE) patent their vertical trawl door. Made of wood and metal fittings, the door is made for demersal use. [GB523452]

Dec 1948 – Robert Larsen (DK) patents his two-boat pelagic trawl in Denmk.

Nov 1949 – Robert Larsen’s (DK) first patent outside Denmark is made in Ireland – the two-boat pelagic trawl, as before. [IE019864]

Nov 1949 – Karl-Hugo Larsson (SE) was, judging by the amount of research he published and was involved in, a key and influential figure in the development of pelagic trawling. This is his patent for a one-boat pelagic trawl with vertical trawl doors. The vertical doors in this case are curved, very much in the manner of Suberkrub’s patents. [GB670222]

Larsson’s patent GB670222

Nov 1949 – Robert Larsen (DK) makes a British patent for his two-boat trawl. [GB695361]

Nov 1950 – Sterner Persson (SE) patents his trawl capable of functioning at different depths – primarily a pelagic trawl. The trawl has three trawl doors – two at each side, and one from the ground rope to keep the net open. The trawl doors in the more traditional location are vertically orientated. [GB682824]

Feb 1952 – Jon Sigurdsson (IS) patents a pelagic trawl, with a third trawl door attached to the ground rope and horizontal trawl doors. [GB699206]

Aug 1952 – Another Icelander, Agnar Gudmundsson Bredfjord, patents a pelagic trawl. This trawl has the hallmarks of a modern pelagic trawl and has vertical trawl doors. His patent states that one of his reasons for pelagic, rather than bottom fishing, is to not disturb the vegetation and small fry that may be on the seabed. [US2771702]

Breidfjord’s patent, US2771702. By far and away the prettiest, too.

Nov 1954 – Robert Larsen (DK) isn’t taking any chances; this is his Canadian patent for the two-boat trawl. [CA507700]

Dec 1955 – Karl-Hugo Larsson (SE), who made his one-boat pelagic trawl patent a year or so after Robert Larsen in Britain follows his lead and makes his patent in Canada as well. [CA519107]

May 1957 – This time a man of unknown nationality, Donald S Johnson, has his invention patented on his behalf by the Dominion Textile Company, Canada. The patent describes a one-boat pelagic trawl with what appears to horizontal, tubular trawl doors. [CA541497]

Dec 1958 – Moises Larrea Esesumaga (PT) patents a trawl for working at varying depths, from surface through to demersal The trawl has no trawl doors, instead relying on four kites at each corner to hold the net open – the shape of the mouth of the net being controlled by ‘guides’. [GB911666]

GB911666, Esesumaga’s patent

June 1959 – Franz Suberkrub makes a solo patent, for the vertical trawl door. Now designed for pelagic rather than demersal trawling, this door is now a sleeker, version of the 1938 version, no longer being made of wood. [US3079720]

So that’s the boiled down version – the real one is a lot longer and a bit more complicated. But at least you can all see the basics from which I am expanding and researching from. That and having to teach every word-processing programme I come across the word ‘demersal’. Non of the seem to recognise it!

Patents… Continued

It’s been a little while since I posted – largely because I have been engulfed by a pile a paperwork that I can say, without even a hint of a fib, is bigger than my head. I made the mistake of printing off an enormous pile of patents with the intention of sorting and reading them in a few days. Having severely underestimated my speed reading ability and making some sacrifices, two weeks later I am facing the last 50 or so. This coincided with another set of papers, a pile of potentially relevant reports in pelagic fisheries in Britain from the 1950’s and 1960’s. Once the patents are entered into my database and put to one side I can finally look at them! It also means that I can stop wittering on about patents to whoever will stand still long enough to listen.

For now I can use the look at the database and see more than a few obvious trends. Last time I posted about profession, but this is a limited, if intriguing window to the past. After the First World War profession is no longer stated on patent applications, being replaced, it seems, with a declaration of the applicant’s nationality. Looking instead at the addresses of those applying I can see straight away some familiar names – Grimsby, Hull, Aberdeen, Fleetwood and Milford Haven. These are by far and away the most represented, with a smattering of Edinburgh, Gravesend and the Tyne area. This is also something I will try and pursue a little further, as I would like to see if the number and concentration of applicants reflect the status and economic power of the ports and harbours they come from. But what caught my eye when I scrolled through my work so far was how few examples there are of vertical trawl doors.

Only four examples popped up. these applications were made in 1897, 1898, 1938 and 1959. That last two were made by Franz Süberkrüb, while the earlier come from very different places. The 1897 patent as made by “… Johann Cohrs of Grosse Elbestrasse, Altona-on-the-Elbe, German Empire, Fish Auctioneer…” Well, for a start ‘German Empire’ is very much a voice from the past that many would like to forget. But the patent itself is intriguing, albeit somewhat irrelevant to the overall Pelagic theme, as he puts in with his description of the ‘heavy rollers… for facilitating the passage of otter boards over the ground’. So Johann Cohrs starts off very promising, but ends up as a side note in the overall assessment of trawl doors. His contemporary, David Sherrit, and Engineer from Aberdeen, takes a completely different approach to the vertical trawl board. His is very much a door – attached in a manner above the net – and as such does not need to touch the ground. Of course, on of the things that I have to keep in mid when looking at all this, is that there might not be any documentation for something considered completely normal – so when David Sherrit also states they may be “… ordinary otter boards…”, I could be missing out something here. Ultimately, however, these two are footnotes in the progression of technology that led to the rise of the pelagic fisheries.

It is the patents by Süberkrüb that lead us back to familiar pelagic territory. First, there is Süberkrüb’s 1938 patent application for vertical, curved trawl doors. Although I have no doubt that a proper fisherman would look at the design, I found myself drawn to the individual details: firstly, that the patent is shared with two other inventors and secondly, that the application was made in 1938 – and accepted in 1940. Given that all three applicants are from the Hamburg area and declared as German citizens, it leads me to wonder what was going on in the fisheries at the outbreak of the Second World War, and the more precise events that surround this patent, at this time. It’s certainly something I mean to explore as much as possible in the next few months. His later, 1959 application is more telling in its differences. Süberkrüb makes this application alone. Like his 1938 patent, he lives in Hamburg – and I wonder what happened to his colleagues. The 1938 patent was made in Britain, the 1959 one in the USA. The design, the principles behind the two patents are largely similar, but what is striking is the change in materials. In 1938, it was wood and metal fittings, formed to make a curved panel. By 1959, the wood is gone – “… wooden otter boards are unsuitable…” – and the suggestion is for metal or even plastic. On paper it looks very sleek and modern, with a sparse two page explanation paring down the science behind it.

One of the things i am looking forward to doing with this project is looking at more than the technology and politics. I am making it very much a key part of this research to look closer, not just at the historical facts but the personal stories of the individuals of the people who made historical fact. At the very least, it’s going to be an interesting journey, regardless of absolute relevance in the end.

Süberkrüb's 1938 patent no. GB523452

Süberkrüb's 1959 patent no. US3079720