The Duchess was a small sightseeing vessel used for tourist excursions along the Chesapeake Bay before the war. Tobar’s grandfather found her and, with the help of his caravan, restored the boat’s boiler, allowing the vessel to be powered by steam heat from any fuel that will fit inside the burner.
Tobar sells the player tickets for 330 caps each (with 100 Barter, having Master Trader in addition drops the cost to 300), although, upon proceeding far enough into the main quest line, the player is able to ride for free when Nadine takes command of the ferry.
After boarding the ship, there is a small engine room on the right and a guest room to the left; this is where passengers reside during the month long voyage to Point Lookout. On the left side, is also a stairway that leads to the second deck of the ship. There is a steering column in the front and a row of benches in the middle.
Likely due to design oversight, when on the deck of the ferry you can hear the engine chugging away quite loudly, but it is completely silent inside the engine room.
The only way to transport items between the Capital Wasteland and Point Lookout, other than in inventory, is in Duchess Gambit's footlocker.
Blood will spatter if you shoot the mole rat-skin rug just inside the cot room door.
The sound effect of the Duchess Gambit may continue if you fast travel while standing on it
Items placed on the table at the end of the players bed will appear underneath if you fast travel back after long enough.
When Nadine takes over the ship, if you still have a Riverboat ticket, it may be taken away when going back to the Capital Wasteland or coming back to Point Lookout.
↑Fallout 3 Official Game Guide Game of the Year Edition p.101: "Tobar the Ferryman Tobar is a living reminder that the world will always have a place for the savvy and charming trickster. Tobar is captain and crew aboard his steamboat the Duchess Gambit. The Duchess was a small sightseeing vessel used for tourist excursions along the Chesapeake Bay before the war. Tobar's grandfather found her and, with the help of his caravan, restored the boat's boiler, allowing the vessel to be powered by steam heat from any fuel that will fit inside the burner. Tobar has various ports of call along the Atlantic Seaboard. Tobar's current career as a ferryman revolves around the Punga fruit produced at Point Lookout. The tribal leader of the fruit farmers has struck a gruesome bargain with the ferryman. By way of exchange, Tobar is permitted to export the considerable surplus of Punga fruit produced by the commune every lunar cycle. Tobar takes on passengers whenever possible. Not only does he usually negotiate a considerable fare from the passenger, but most who visit the commune at Point Lookout join it, each time creating a new opportunity for Tobar to earn his next Punga shipment. Tobar has long since decided that something must be off about that fruit, and he's not touched the stuff since." (Fallout 3 Official Game Guide Game of the Year Edition Wasteland Census)