Monthly Archives: June 2016

  • It Used To Be Not If, But When!

    Anything taken underwater that has an air-space within it will have a tendency to leak. This sad fact of life used to be never more true than with cameras. There was even the once ironically named Society of Nikonos Flooders! So the philosophy of underwater photography combined with the realism of the likelihood of a flood coined the advice, “It’s not if, it’s when.”

    So why does something that is designed to keep the water out, let the water in? Well, it’s all down to the fact that you need to access a submarine housing from time to time, whether it is to renew a battery or replace a memory card. The seal at the point of entry is usually effected by an O-ring that sits it a groove and abuts another surface when the unit is closed up. If the point of contact between the O-ring and these surfaces is not scrupulously clean and smooth, free of any foreign bodies like hair or grit, the seal will be broken and water at the pressure of depth will hose through the so-caused gap.

    The O-ring must be lightly greased. This does not help it seal but simply allows the O-ring to flex and move as the two surfaces are offered up to each other. Too much grease can in itself cause a leak. You should just put on enough to make it glisten.

    Passing a clean O-ring between your lips can help you detect if it has any grit or hair clinging to it and you might do this before you re-grease it. O-rings are often supplied with camera housings as spares but the original will never wear out. You would need to damage it with a sharp object for it to need replacing.

    So keeping the opposing surfaces smooth and clean and placing a clean lubricated O-ring between them should maintain a perfect seal – but bad things can still happen. Using the wrong type of grease can cause a leak. If you use silicone grease on a silicone O-ring, it can cause it to swell or start to dissolve. Use the right grease - an environmental silicone - even on neoprene O-rings.

    Don’t leave your rig in a fresh water rinse tank. Other divers may not be so careful about your precious kit and a careless collision with another object being rinsed could cause some catches to come undone.olympus_tg4_package_1

    Isn’t there a better way? Well, yes there is. If you want a compact camera, what about the Olympus TG4 in an Olympus housing? You will need to maintain the main O-ring of the housing in much of the same way as you would any other make of housing but the TG4 has a second line of defence in the event of an ingress of water into it. The Olympus TG4 is itself an amphibious camera and can be used down to 15 metres deep just as it is. Put it inside it’s housing and, should the housing be found to leak, you will only need to ascend to 15 metres deep and later, open the housing and rinse it in some fresh water and dry it, before you are ready to reinstall it in its housing, first having discerned what caused the leak in the first place.

     

    nauticam_na_g7xIf you go for a compact in a more elaborate housing, buy a Nauticam and spend the additional £191 on a vacuum leak-test kit. These vacuum leak test are available on bigger more expensive Nauticam housings for bigger and more expensive cameras and nobody in their right mind would eschew the chance to never suffer another leak again.

    The vacuum leak test as an integral part of a housing was first introduced by Hugyfot. These housings are available only for more expensive cameras but when they were first introduced many years ago, several owners suffered flooded cameras. The problem was that these housings are securely sealed and locked using bolts. These bolts were sometimes not fastened tightly enough and when the clamshell housing was pushed together by the intense pressure found at depth, the bolts could work loose. When the diver ascended to a lesser pressure, the two halves of the clamshell housing could become loose and a flood was the result. The Hugyfot vacuum leak-test was the answer to this problem (now included as standard equipment on all Hugyfot housings) and Nauticam has more-or-less adopted a similar system.hugyfot_canonmk3_front

    This is how it works: The camera is sealed inside the housing with a lightly lubricated O-ring to seal out water, as usual. A pressure sensor within the housing confirms it is working and a (red) LED signals that the air inside the housing is at the same pressure as outside.

    The air is then vacuumed out of the housing via a special one-way valve using the pump provided. The pressure sensor inside detects that the air pressure is suitably reduced and a green LED shows. Green is good.

    The user then waits to see if the green light remains or whether a red light will show instead. It is recommended to wait around 20 minutes. If no air has leaked in, no water will leak in. Depressurizing the interior of the housing has a secondary benefit. Outside air pressure pushes the two parts of a clamshell housing together so firmly that you need not do up any bolts or close catches (should you forget) and you literally cannot prize the two parts apart without letting air back into the housing via the valve provided.

    nauticam_5dsrSo this cured at one stroke, the problem of Hugyfot users not fastening the housing bolts sufficiently, as well as ensuring there was going to be no leak. Hugyfot cured this design/user defect at one stroke.

    Underwater photographers find that winking green light to be very comforting on a dive and never open the valve to let air into the housing until they are out of the water and done using the housing. Now it’s not not-if-but-when, it’s green ensures your costly camera will survive!

     

     

     

  • Truk Lagoon - a Trip of a Lifetime

    During World War II, Truk Lagoon became the forward operating base for the Imperial Japanese Navy in the South Pacific and as such it was thought to be an impregnable fortress. More than 27,000 men were stationed there and the islands surrounding the lagoon were equipped with roads, bunkers trenches and artificial caves. There were five airstrips, a seaplane base, submarine repair workshops, a torpedo boat station and all defended with heavy guns, anti-aircraft guns and mortar emplacements. Some have described it as Japan’s equivalent of America’s Pearl Harbour in Hawaii. They even had time to remodel an island so that it looked like an aircraft carrier from the air!

    Battle tank on the deck of the San Francisco Maru Battle tank on the deck of the San Francisco Maru

    It was feared by the American Command because they considered that to take it would cost a lot in American lives

    In February 1944, despite the main body of warships escaping to Palau after an American reconnaissance plane was spotted, a massive attack by American bombers flying from a task force of aircraft carriers destroyed the military effectiveness of the Japanese base in Truk (Chuuk)  with 32 Japanese merchant ships (operating as fleet auxiliaries) sunk. Operation Hailstone as it was known resulted in Truk becoming the biggest graveyard of shipping in the world.

    One of the many telegraphs on the Shinkoko Maru One of the many telegraphs on the Shinkoko Maru

    Given the poor state of the Japanese war effort in 1944, few of these vessels had much fuel in them and the amount of pollution was minimal. Though today, most of them are in a poor state, these wrecks make exciting dives and give an insight into life at sea during that period. Most of them are in water shallow enough to be accessible by any open water diver and some of them are metamorphosing into colourful reefs.

    Sight glasses on the engine of the Kansho Maru Sight glasses on the engine of the Kansho Maru

    It’s a long way to travel from the UK, via Singapore, Manila, Guam to Chuuk, but it’s a scuba diver’s trip of a lifetime and should not be missed. If you go, remember to go equipped with some sort of camera so that you can bring back memories of your experience. The most interesting parts of the wrecks are their engine rooms and cargo holds so you will need some effective lighting in order to capture rewarding images. You’ll need an underwater strobe together with an aiming light that automatically extinguishes when you take a still picture. For video, you’ll need powerful video lights that give even illumination across the field of view. A wide-angle or fish-eye lens is essential if you want to capture more than details, so don’t go without one.

    Submarine periscopes in a companionway of the Heian Maru. Submarine periscopes in a companionway of the Heian Maru.

    It’s a pity to go all that way and find that you regret saving the cost of the right equipment to take with you!

    Come into Ocean Leisure Cameras and discuss what equipment you need to come back with meaningful images of your trip of a lifetime.

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