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Help with early Undersee Products Equipment Research

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.
Thank you so much for those images, Mel. It's the first time I've seen those Undersee fins. I managed to track down the drawing for that Frank Minto Cunliffe diving mask, Australian Patent 114,992 of 1941:
 
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Rubber compounding very much affects fin performance and durability. Often clay was used as a filler, especially on non-black items. Carbon black strengthens rubber, that is why vehicle tyres are black, but there are also antioxidants and UV inhibitors added to rubber compounds depending on what they are to be used for. In the early days the dive equipment manufacturers were not fully on top of this and their products could go gummy, or rip or crack, hence these products could not survive for decades unless they were stored in talc and out of sunlight and even then the mechanical properties would have been lost. Modern rubber fins have a much longer life, but will succumb eventually to oxidation and reversion of the rubber. As for plastic fins, well who knows, but they are made with a much wider range of materials. The tear strength of silicone rubber is reduced, that is why fins are not made of the stuff.
 
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Indeed. This from page 24 of my copy of Joan and Van Ellman's The Young Sportsman's Guide to Skin Diving (New York: Thomas Nelson & Sons, 1962):

"May not last a summer": so fin purchasers, and presumably fin manufacturers too, would have been aware as far back as the early 1960s of the shortcomings of rubber blending with clay fillers. Higher-grade natural-rubber and neoprene fins, particularly the carbon-black variety you mentioned, Pete, tended to pass the test of time much better. The oldest fins in my modest collection are a pair of Typhoon Speedmasters, made in England by E. T. Skinner and Co. in the mid-1950s and with foot pockets still as soft and pliable as they were when they were bought:

I also have a Typhoon Super Star mask and a Typhoon T1 splash-cap snorkel of equal longevity in my collection, none of them displaying any signs of perishing six decades later:


Keeping such gear in a cool, dark place certainly helps with their preservation, but so does using quality materials in the first instance. The same goes for my Giant Continental fins, one made by Turnbull and the other by Hanimex, in Australia in or around 1969 when the latter took over the former manufacturer. Though missing their instep straps and buckles, they remain in pretty good shape, free of perishing, half a century later.
 
Undersee spearguns are often associated with their mortice trigger mechanism which is set into a timber stock and has a folded metal sear box with an angled opening at the rear. Originally the guns had inverted plane handles as used on the woodworking tool, but later variations had a cast aluminium handle of similar shape bolted underneath which from memory incorporated a seahorse decoration on the sides and was anodized in a blue finish. Later guns were developed using nylon mouldings which initially were royal blue in colour mounted on timber stocks. These moulded parts also opened the way for tube guns using alloy tubing barrels. At that time guns began appearing with a nylon moulded sear box set into the plastic grip and eventually in the late sixties these were joined by black versions, a photo is attached. The "Bazooka" was a long running model and had an alloy, later cast steel and vinyl coated muzzle that carried two bands set in metal sleeves imprisoned by the cast metal upper against the timber stock that it was screwed onto. These muzzles incorporated a bayonet that was pointed rather than sharp for pushing away Wobbegongs (carpet sharks) that became too curious about your catch. Bazooka guns often had a fore grip created by the factory slicing away the front of a grip handle and removing the trigger finger guard. Guns tended to be rough and ready rather than the blemish-free items one sees these days, I remember sorting through a bunch of Undersee guns in a rack to find one that was a bit better screwed together than some of the others, but they all worked OK and nothing was flimsy.


Alloy handle "Bazooka" using the mortice mechanism and the cast alloy bayonet muzzle. Note the metal sleeves trapped under the muzzle casting.
 
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