Docking a ship

It's essentially a metal box with windows and a door aft. It is taller than wide and large enough to house one or two occupants, a helm console (throttles and engine mounted gages here), compass binnacle (a small one, on top of the console), a radio mounted on the overhead (often, just a handheld walkie talkie) and a horn. There is often a small mast for navigation lights and a flag. I've seen a very few with a navigation radar.I found this picture showing a sea mule in the foreground. Its pilot house is a little larger than usual, but not too much. Actually, this is a pretty nice sea mule.

 You can find a nice resin model of USS Vestal AR4 (1941) at commander series models.  Hank  Support the troops  Garry owen

Who makes a model of the Vestal and in what scales?

Scott

A seamule is a type of tug - similar to a river towboat.  It usually has a small pilothouse structure on it, and a pair of push knees on the bow. 

"The Last Mooring" by Tom Freeman should give you some ideas.  It depicts the final  mooring of the Arizona at Pearl, before the Vestal came alongside. 

Note the tug in the mid-distance.  Yard and district craft should have a black hull and Ocean Gray (5-O) upperworks.   Corsair Armada makes a 1:700 scale model of the USS Hoga, a tug who assisted several ships, including the Nevada on Dec 7.   Battlefleet Models makes several tugs and yardcraft , including YTL-17, lighter that was instrumental in fighting fires. 

Iron Shipwright makes a 1:350 scale model of the Hoga.