CHALLENGE: WMD Squared submitted a proposal to be awarded the engineering and design work for a US Navy marine universal fender.
APPROACH: WMD Squared’s approach to designing this submittal fit all of the US Navy’s current requirements along with many improvements over the US Navy’s design. Some of them include:
- Tubular members used in place of the previous design which used a number of beams and plates. The tubular design has less surface area, therefore less area to rust and corrode, yielding a longer life
- The upper and lower padeyes are fabricated from stainless steel, which is more durable and also doubles as a mounting bracket to attach the float to the triangular weldment
- The substructure for the float is made of carbon steel but coated entirely in anti-fouling paint. All of the hardware protruding from the unit is stainless steel with the heads seal welded instead of using nuts which have a natural leak path across the threads, thus giving the unit a more watertight construction
- The original arch style fenders specified by the US Navy were used over the trapezoidal fenders. The arch style is not typically preferred because of the number of bolts required and the side plates are prone to corrosion due to being exposed to salt water on both sides. After researching the options, it was determined that the original fenders had a much better energy absorption characteristics and a much lower reaction force. This will lead to less stress on the unit, and better berthing characteristics
- An option was added to use full length rods placed across the width of the fender to reinforce the welded side plates, thus improving the shear strength of the fender mounts
IMPACT: The design was completed and submitted to Oceanetics (formerly Truston Technologies Inc.) for a bid with NAVSEA at the US NAVY. With the complete design package Truston was able to accurately estimate and quote all phases of the design from purchasing material to fabrication, coating and weld inspection. The project was won and the build was a success. The units remain in service today.