V bottom freighters:

These are very able working vessels, and range from 46 to 125 on deck. The smaller ones, up to about 60, often have a modest working sail rig.  Occasionally, as illustrated above, the sailing rig is enough to actually sail without the use of an engine. To do this, it is necessary to use either a long shoal keel or a centerboard to give them windward ability.  In the case of this vessel, at 46, the centerboard was not an option due to the fact that the hold had been converted into a machine shop, including welding machines.  The owner planned to travel to various small communities and islands to ply his trade.  One of the welding machines was diesel powered, which permitted him to go alongside an anchored vessel to perform any repairs that were needed.  However, for the other machinery, it required that he be dockside and have shore power. The house located just ahead of the pilot house is the engine room, and access is only via the pilot house.  A watertight bulkhead is located at the after end of the pilot house, which separates the steering gear from the remainder of the machinery and storage area. For other vessels with sails on them, there is no pretense of windward ability; therefore, they are very shoal draft in the light condition. These vessels are often deeply laden to the point where there is only 2 or 3 of freeboard left.  Enough reserve buoyancy permits this, even though I do not recommend it. When the owner/master habitually loads his vessel this deep, the water-cooled exhaust lines are run across the deck; otherwise, the exhaust lines outlet would be under water. 

What this family has in common is that they all have a plum stem. The majority have a round stern, although a few such as the 22.3 meter (73) ATLANTIS, which is a dive boat, have a square stern. In her case, a portion of the stern hinges down to form a dive platform and opens into a watertight well deck. This vessel was built in Thailand and operates under Thai regulations. With accommodations for 24 persons, she would not pass U.S. Coast Guard regulations, but does have positive stability at 90.  She has a range of 5,000 nautical miles. 

If any of these hulls were converted to yachting purposes, then the engine and fuel tanks should be very close to her center of floatation so that there would be a vertical, or nearly vertical, rise as the fuel tanks are emptied.  Of course, the pilot house would be directly above the engine room. I have long favored absolute watertight and oiltight bulkheads at each end of the engine room, and prefer to enter the engine room via a hatch located in the pilot house. This provides the ultimate in safety. Most yachtsmen prefer to walk in and walk out of the engine compartment, which can be done; however, in doing so, space is lost both in the engine room and the compartment from which one enters. In any case, the engine room should be kept spotlessly clean, and preferably painted white. I know of one captain who, after shutting down his engines, wipes everything down, and then does the final wiping down of the engines with Kleenex. His engine room was cleaner than most galleys.

At about 60 and above, it is possible to have complete accommodations below the main deck as well as accommodations above the main deck. In still larger hulls, it is possible to have a boat deck as well as a pilot house on the boat deck.