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All I put this mail together for a fellow diver in the UK who was asking how I set up my short body WKPP scooter and thought it may be of interest to others. All of this may be teaching your grandmother to suck eggs but here it goes anyway... The batteries are set asymmetrically in the battery housing so that the centre of gravity is off centre. With the batteries in the housing and the housing resting on the floor, the housing should roll freely but come to rest with the terminals uppermost. These are then inserted into the scooter so that the scooter floats with the handles at 3 and 9 o'clock and the battery terminals are at the highest point. I put some electricians tape around the bulkhead rims to increase their diameter and create more friction so that the battery housing did not rotate inside the pressure vessel when I executed tight turns or barrel rolls. With lead acid cells, the scooter should carry ballast for the water in which it is going to be operated. I added 700g (2 by 350g) at the lower battery bulkhead affixed to the wooden spacer to achieve ever-so-slightly negative buoyancy at the surface in fresh. I add additional weight for sea water which goes in the nose cone. I think this is something like 800g so that the scooter floats on the surface but goes neutral at about 12 m, and negative any deeper. Whether in fresh or salt, and whilst not under power, the scooter will be nose-up in attitude. The tow cord should be a single length of rope. I use 4 mm (I think) braided, white nylon line. This is the same rope as that on my stage bottles. Make sure you have an excess of cord to allow for adjustment. Don't forget to seal the ends of the rope by melting them. Do not cut off the excess until you have done a few dives and are happy with the setup. However, beware of leaving danglies near the prop. The length of the tow cord from the SS swivel bolt snap to the left and right handles should be of different length so that the scooter runs parallel to and slightly below your body when operated single handed. In this way the prop wash passes under your body and the whole setup is streamlined. Form a large bowline at either end of the tow cord. Take one bowline and turn the loop back on itself to create a slip loop. Put the slip loop over one handle and pull tight. Repeat for the other bowline and handle. To connect the SS swivel bolt snap, take the middle, or thereabouts, of the tow cord and pass it as a loop through the eye of the bolt snap swivel, loop it over the body of the bolt snap, and back down passed the eye. This should now have formed the same type of slip loop as is on the handles. With a loose slip you can adjust the length of the left and right sections of the tow cord to set the attitude of the scooter to run parallel to your body. This type of loop can be adjusted easily but will not accidentally change its setting once pulled tight. You then need to get in the water to fine tune the total length of the tow cord. Minor adjustment in overall length is best performed by changing the size of the bowline loops. Once this is done, you can then adjust the position of the bolt snap on the tow cord to allow parallel-to-body operation of the scooter. Having the scooter further away from you is more streamlined, so I set it for one-handed operation with my right arm nearly straight i.e. only a slightly bent elbow. When setting the position of the bolt snap when in the water, it is best to test it by scootering along a section of flat sea/lake bed which is at a constant depth. Scooter single handed (right handle at 12 o'clock position or thereabouts) and parallel to the sea bed. If the bolt snap is correctly positioned then the scooter will continue to pull you parallel to the sea bed without any need to steer. If it is wrong, you will find the nose rising or falling and feel the need to steer. When you think you have the position correct, scooter on maximum speed to amplify any remaining need for fine tuning of the setup. After a few dives and when I am happy with everything, I mark the position of the bolt snap on the tow cord and trim off any excess ends of the tow cord and reseal the ends. When scootering single handed, you should find that the right handle rotates from the 3 o'clock position to 12 o'clock or thereabouts. This is due to the prop thrust but is counterbalanced to a some extent by the asymmetrical centre of gravity caused by the asymmetrical positioning of the batteries. Steering. It took me a while to realise that to turn the scooter right, simply push/rotate the trigger handle from 12 o'clock to 3 o'clock or more, similarly to turn left push/rotate the handle through 9 o'clock. You do not need to turn using your wrist! This makes for effortless single handed tight turns! I've been diving my scooter since it arrived just in time for Christmas 1997. It took me a while to set up and I found it initially added significant task loading to my diving. However, with practice it soon became a pleasure and breeze to use. It is now a regular part of my dive equipment and I am very relaxed with it. Many thanks to George and the rest of the WKPP for designing and building this beautifully crafted scooter for me! David Shimell Project Manager, Sequent Computer Systems Ltd., Sandton, South Africa. Email: shimell@se*.co* <mailto:shimell@se*.co*> -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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