Builder:Merwede, the Netherlands
Owner/Manager:Mammoet Shipping
Length oa:138.04m
Breadth (moulded):22.80m
Draught:9.513m
Happy River's heavy lift mast cranes have been designed and manufactured by Rotterdam-based Huisman-Itrec. They are mounted on the starboard side of the vessel. There are two main cranes. Each has a lift of 350t at 20.5m radius, 400t at 18m radius or 250t at 28m radius, and when arranged to operate in tandem, give the vessel the capacity to handle loads up to 800t. The jib's working range is up to 83°. They have a hoist speed of 1.8m/min at 400t capacity, and 7.2m/min at 80t load.
The Happy River main engine is a Wärtsilä 9L46B unit, with an output of 8,775kW (11,760bhp) at 550rpm. This is connected to a Renck Tacke HSU 1200 gearbox. It uses a Lips 5m-diameter four-bladed CP propeller and shaft.
For manoeuvring, the Happy River also has a 1,800rpm, 850kW bowthruster.
The propulsion system gives the vessel a speed of 16.4 knots draft 7m or 15.6 knots at 9.5m draft.