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Float Fabrication
To create the fin sleeve, a PVC union coupler was machined in a lathe to remove the inner taper and the stop.
A comparison photo between a brand new union coupler (left) and a machined fin sleeve (right). The inner stop and taper were removed. The exterior was faced; leaving the matte finish seen above.
A mill was used to machine the slots in the fin sleeve that accepts the fin tabs. An indexer was used to ensure that the slots were 90 degrees apart to create perpendicular slots.
The fins are receiving two tabs that were used to mount them into the slots on the fin sleeve. All four fins were clamped together and machined at the same time to ensure that the tabs were the same size.
The fins received a small round over to soften the edges and allow the fins to cut through the water easier.
Pictured is the prototype float. The float was used for the initial static trim test and dynamic test to verify calculations and performance.
Static Test Performed at Canyon View Pool
A side view of the float in the water showing the static test set up. Inside the bag is 60lbs of barbell weight. The bag was used to prevent scratching the pool floor. The bail was connected to the waits using a carabiner and rope.
A perspective from the front of the float while underwater. The cross sectional area is minimal and will help reduce drag from the ocean current.
First Transdec Test
Members of the team are pictured with the float in front of the Transdec Pool Facility at SPAWAR. The actual testing facility is the structure in the background.
An image of the anchor used to tether the float from reaching the bottom of Transdec Pool. The line is rigged with a shock cord (black) to help slow the float and weights. A bite of rope is rigged with the shock cord to serve as a hard stop in case the maximum stretch is reached.
The float is shown in the Transdec Pool prior to running a drop test. The floor boards inside of the facility are easily removed to allow instruments to be lowered into the pool. Pictured is the prototype float. A makeshift bail was constructed from rope and secured using a hose clamp.
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