EBDG was retained by Hvide Marine to support their effort for an innovative tug concept for ship assist operations. After several iterations, the resulting Ship Docking Module (SDM) was designed with two Caterpillar 3516 engines rated at 2000 BHP at 1600 RPM, each driving Ulstein azimuthing units. Three vessels were built by Halter Marine to this ABS-approved design.

The patented design featured asymmetric drives with the towing bitt for ship handling located near amidships. The ABS approved bollard pull is 104,000 lbs. in a forward or astern direction and 90,000 lbs. transversely. The SDMs have proven to be outstanding ship handling vessels with a crew of two. The SDMs are also equipped for off-ship fire fighting, having a 2000 GPM capacity and a 3% AFFF proportional foam delivery system.

Since the original flight of three vessels, Hvide (now Seabulk International) elected to build three additional vessels. These new vessels, which are now referred to as the SDM Mark II class, have the deckhouse located further forward which allows the towing bitt for ship handling to be located at mishap. The SDM Mk II uses Wartsila medium speed diesel engines and larger propellers.  As a result, the bollard pull has increased to 120,000 lbs. in the forward and astern direction and 110,000 lbs. transversely.