Model Boats|November 2019
The model required identification; first I had to give it a name, I decided on ‘Serenity’. This name suited this craft, because it means slow or graceful.
The company name, ‘Perry Oceanographic’ was applied to the model using rub-on letters, but the name, ‘Serenity’ was a challenge due to the introduction of computers. Rub-on letters were, at the time, disappearing - now they have!
To over-come this problem, I had to make my own transfers. The name was typed out on some gummed paper (really going back in time here). The gummed paper was sprayed in polyurethane, and once dry, the name was cut out and placed in water. Eventually, after approximately 15mins, the name simply separated from the gummed paper, and like a transfer, slid onto the model middle canopy and stern section. Now days a photo is taken of the original craft; scaled in Photoshop, then printed off onto transfer sheet.
Weathering is a make or break issue on most models, but with a submersible, they are made from high quality materials, such as stainless steel and glass fibre, they don’t go rusty! Even old submersibles look clean; therefore, the only option I had, was to lose that pristine look. I took some brown and black dirty thinners and placed very small amounts of this solution and coated the handrails and the view ports studs and hatch hinge etc. The model was finally sprayed using Satin polyurethane for a protective coating.
With the model placed in the normal type test tank, it was found to be 136gms too heavy. This was rectified by placing small segments of high-density foam on the model’s hull, but placed out of view, under the canopy, with double sided sticky; this was a temporary measure. The segments were moved until the model was level on the surface.
The transmitter stick was operated slowly, so the model took on a very slow controlled dive. The bow started to slightly dip. The water slowly lapped up the hull’s length, until the stern lost its grip with buoyancy; with the model under water, it levelled off nicely.
With the transmitter stick moved quickly to full travel position, the bow took on a deeper angle and the model slipped under the surface within 7.2secs. If the transmitter stick is placed in such a position; where the deck is floating level with the surface, then the dive time is 4.18 seconds.
The model was tested in warm water at my local swimming pool and very cold water at my local club. The model seems to function with no diving problems but there did seem a signal problem, so the aerial was moved from the inner hull a laid inside the canopy. I phoned the pool staff, explained the situation and they allowed me to return; this time everything was 100%. There is a trim weight in the hull, near the propulsion motor operated by the transmitter, however, I only found two occasions where it was useful. One was when the model was placed at the bottom of the ocean, and the ground under the model was not level, then the transmitter stick could be moved, so the model took on an angle equal to the bottom. This gave the model a nice landing and less chance of the model receiving any damage.
Whilst trimming a scratch-built model questions are raised; will the model float? Will it dive? etc. On that note, I would like to offer two tips for beginners; 1) the ballast tank should be approximately a third of the size of the pressure hull; 2) I came up with this simple formula many years ago, if you obtain an approximate volume of the ballast tank in square inches and times it by 0.36127, the answer is the amount of weight in pounds that the ballast tank will support in fresh water; it’s that simple.
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