T-top
Short, aluminum tower with overhead canvas to protect the helm.
tack
The lower corner of a sail. Also, each leg of a zigzag course.
tender
See dinghy.
through-hull
A fitting or object that goes all the way through a hull.
tiller
A bar connected to the rudder and used to steer the boat.
tiller handle outboard
A small, outboard motor that uses a handle fitted with engine controls to steer instead of a steering wheel.
tongue jack
Adjustable jack on the trailer tongue that raises and lowers the coupler.
tongue weight
The measurement of trailer weight when loaded with a boat on the hitch ball.
topsides
The hull above the waterline. Also, everything above deck as opposed to below deck.
tow rating
Maximum weight a vehicle is rated to tow.
trailer tongue
Forward portion of a trailer where the coupler is mounted.
trailer winch
Device that uses a crank and cable to assist in launching and retrieving a boat.
transducer
An electronic sensing device mounted in a boat's bilge or at the bottom of the transom to provide data for a depth sounder.
transom
The rear section of the hull connecting the two sides.
transom shower
A plastic hose and shower head located near the transom that draws from a fresh water supply.
trawler
A pleasure boat more than 25 feet in length with a displacement hull.
trim
The way a boat floats in relation to the horizon, bow up, bow down or even. Also, to adjust a boat's horizontal running angle by directing the outboard or stern drive's thrust up or down. Also, to set a sail in correct relation to the wind.
trim tabs
Hydraulically adjusted horizontal plates located on the bottom of the transom that control the trim angle of a boat at speed.
trimaran
A type of boat with three side-by-side hulls, the center of which is usually larger with crew accommodations.
trolling
To fish by towing an array of baited lines or lures behind the boat.
true wind
Direction and velocity of wind as measured on land, distinct from apparent wind.
tuna tower
Tall aluminum tower used for spotting fish in the distance, often equipped with a second set of helm controls.
two-cycle engine
A gasoline- or diesel-powered internal combustion engine that takes two cycles or strokes of the piston to complete its power phase. Also called two-stroke engine.