amidships - a condition of being totally surrounded by boats.

ANchor - a metallic device, usually attached to a rope, a line or a chain that was
                 designed to bring up samples of mud and other bottom laying debris.

anchor light - not to be confused with coors, miller or bud light, usually a
                           small white light that's main purpose is to successfully drain
                           the battery.

astern - evil type of "look" received by significant other when you talk about
                or purchase "stuff" for your boat.

berth - a new, little addition to the crew

bilge - where all things lost or dropped mysteriously end up.  from tom f

capsize - something needed to know when you want to purchase a new hat.

chart - a type of map that reveals the exact position of where you have run
              aground at...... from larry s.

dead reckoning - any course that leads directly to a reef or underwater
                                 obstruction.

deck - what will happen to you or what you will hit if you spend too much $$$.

deviation  - anything other than the captains' direct orders.

dinghy - the sound that the ships' bell makes.

displacement - ship or boat - when, after docking your vessel, you cannot seem to
                            be able to find it.

dock - somebody in the medical profession......from ronny d

estimation of position - a spot on a map or chart, marked, in which you are
                                             positive that you are not.

first mate - not to be confused with  eve, but it is a vital crew person, a crew
                       person needed for the captain to practice yelling instructions at.

foul wind - a movement caused by flying poultry

harpoon - a dining utensil belonging to the skippers' better half and not to be
                    confused with hisspoon.

heave-ho - this is what happens when you eat too much ho.

hull - famous hockey player (bobby)

keel - main intent of crew after too much abuse from captain.

landlubber - anybody on a vessel who wishes they were not.

latitude - any unspecified amount of room, given to a guest, allowing them to
                    stray off course.

mast - a religious ceremony given before getting underway.

mizzen - something hat can no longer be found.

no wake zone - a specially marked area on the water where you are not
                            permitted to awaken sleeping boaters.

starboard - a unique piece of wood, used by captains for navigation purposes.

through the hull fitting - a leak!

wake - part of a funeral that is sometimes confused with boating.

wave - various hand gestures made to other boaters

Know of any more?  If you think you have any or have found or created some, please pass them on and you will see them here.