Based on a Robert Allan design the vessels have been developed from a whole series of similar 4000 bhp vessels built at East Isle for use within the Irving group and for external customers. The Panama vessels have a lower profile, a different deck layout and underwater shape.

All four vessels are designed specifically for operation in the Panama Canal and incorporate the following features; a high bollard pull, exceptional manoeuvrability and precise control, the operator always faces the ship being assisted, the risk of 'girting' is virtually eliminated, and the tugs have a real ability to tow effectively in the 'indirect mode'. Each tug has a length overall of 30.80m, a moulded beam of 11.1m and a gross tonnage (IMO) of approximately 360 tons.

The propulsion system incorporates two Deutz SBV 8M 628 main engines each rated at 2,200bhp at 1000 rev/min, driving a pair of Schottel SRP 1212 FP ACP fully azimuthing propulsion units. Each Schottel unit is fitted with a bronze, 2,300mm diameter, propeller.

One of the owner's specific requirements is that the propulsion units must be capable of being removed and replaced with the vessel afloat. With the engines producing a total of 4,400bhp at their full MCR rating, the tugs are expected to achieve the same performance figures as their predecessors; a bollard pull of 52 tonnes pulling ahead, 47 tonnes astern, with a free running speed of 13 knots.