We are assembling a large collection of boating
and sailing terms.
This will be a great resource for all boaters.
To view the page of terms, click on the letter that the term starts with
To submit a term please email
us.
daggerboard - Similar
to a centerboard, except that it is raised
vertically. Like a keel, daggerboards are used to
prevent a sailboat being pushed sideways by the
wind.
Danforth anchor -
A brand of lightweight anchor. It has
pivoting flukes that dig into the ground as tension
is placed on the anchor. It does not have a stock.
davit - A
device that projects beyond the side of the boat to
raise objects from the water. Typically a single
davit is used on the bow of a vessel to raise an
anchor, and a pair are used on the side or stern of
the vessel to raise a dinghy.
daybeacon,
daymark - A navigational aid visible during
the day. In the United States and Canada, square red
daybeacons should be kept on the right and
triangular green daybeacons should be kept on the
left when returning from a larger to smaller body of
water. Also see can and nun buoys.
daysailer - A
small boat intended to be used only for short sails
or racing.
dayshape - Black
diamond, ball, and cone shapes hoisted on vessels
during the day to indicate restricted movement
ability or type. For example three balls means
aground.
dead ahead - A
position directly in front of the vessel.
dead reckoning - A
method of determining position by making an educated
guess based on last known position, speed and
currents.
deadlight - Fixed
ports that do not open, placed in the deck or cabin
to admit light.
deadrise - The
measurement of the angle between the bottom of a
boat and its widest beam. A vessel with a 0º
deadrise has a flat bottom, high numbers indicate
deep V shaped hulls.
deck stepped - A
mast that is stepped placed - on the deck of a boat
rather than through the boat and keel stepped. The
mast of a deck stepped boat is usually easier to
raise and lower and are usually intended for lighter
conditions than keel stepped boats.
deckhead - The
underside of the deck, viewed from below the
ceiling.
depth sounder - An
instrument that uses sound waves to measure the
distance to the bottom.
deviation - See
magnetic deviation or compass error.
dismast - The
loss of a mast on a boat. Generally this also means
the loss of some or all of the ability of the boat
to sail.
displacement
speed - Also hull speed. The theoretical
speed that a boat can travel without planing, based
on the shape of its hullhull. This speed is 1.34
times the length of a boat at its waterline. Since
most monohull sailboats cannot exceed their hull
speed, longer boats are faster.
displacement - The
weight of a boat measured as a the weight of the
amount of water it displaces. A boat displaces an
amount of water equal to the weight of the boat, so
the boat's displacement and weight are identical.
distance made
good - The distance traveled after
correction for current, leeway and other errors that
may not have been included in the original distance
measurement.
distress signals
- 1 - Any signal that is used to indicate
that a vessel is in distress. Flares, smoke, audible
alarms, epirbelectronic beacons and others are all
types of distress signals. 2 - The alpha flag is the
legal requirement for boats with divers in the
water.
dividers - A
navigational tool used to measure distances on a
chart.
dolphin - A
playful sea mammal. Also a type of fish.
downwind - In
the direction the wind is blowing.
drag - The
resistance to movement.
drawbridge - A
bridge that can be raised vertically to allow boats
to pass underneath.
drogue - Any
object used to increase the drag of a boat.
Typically shaped like a parachute or cone opened
underwater, drogues slow a boat's motion in heavy
weather. Also see sea anchor.
dry dock - A
dock where a boat can be worked on out of the water.
The boat is usually sailed into a dry dock and then
the water is pumped out.
dry storage - Storing
on land. Many small boats are placed in dry storage
over the winter.
ducts - Tubes
used to move air, such as to ventilate an enclosed
area.
DWL - Design
waterline. Also length waterline or load waterline
LWL - . This is the length of the boat where it
meets the water when loaded to its designed
capacity.
