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JMS Engineering Support for Superyacht Launching

31 August 2016

Cradle2JMS Naval Architects performed a technical review of a superyacht launching system composed of a custom steel trailer and buoyancy modules designed and fabricated by Christensen Shipyard. The superyacht launching system was used to successfully launch two 164-foot yachts at Christensen’s Vancouver, WA facilities.


The launches were accomplished using a unique cradle-and-launcher system designed to give the shipyard a safer and more flexible way of getting its yachts into the Columbia River.

Christensen manufactured the 140,000-pound steel cradle to which two large FRP flotation boxes were attached. The boxes provide additional lift in low-water conditions and keep the yacht perfectly stable throughout the launch process. Once the yacht and cradle are floating, the air in the launchers is replaced by water, as in a dry dock, and the yacht is able to safely float free on its own. The custom trailer and buoyancy floats are designed to be assembled and disassembled via bolted connections for ease of storage in the shipyard and used for future hulls with only minor alterations.

JMS performed a technical review of launch load reactions on the dollies used to transport and launch the 164-foot yachts atop the custom steel cradle. JMS developed a hydrostatic and structural analyses model using HECSALV to simulate the launch sequences of the yachts on an inclined ramp. Reaction forces were calculated at the 14 intersections of the hydraulic dolly extension rods with the longitudinal spars.

Both yachts will be will be on display at the 2016 Fort Lauderdale International Boat Show this November.

“I just want to thank JMS for their part in making these launches successful. It was reassuring to know that what we had designed was confirmed through their simulation.”

~ KC Harrison, Engineering Manager at Christensen Shipyard, Ltd ~