ing and thunder, and accompanied
by extremely heavy rain.

THUNNY. _See_ TUNNY.

THUS, VERY WELL THUS, OR DYCE. The order to the helmsman to keep the
ship in her present direction, when sailing close-hauled. This truly
sailor's motto was adopted by the Earl St. Vincent.

THWART CLAMPS OR KNEES. Those which secure the after, main, and fore
thwarts to the rising and gunwales, and which support the masts.

THWART-MARKS, TO A HARBOUR. Two objects on the land, which, brought into
line with each other, mark the safe course between shoals, as those on
Southsea Common act for the Needles, Swashways, &c.

THWARTS (properly ATHWARTS). The seats or benches athwart a boat whereon
the rowers sit to manage their oars.

THWART-SHIPS. Across the ship, or from one side to the other. (_See_
ATHWART.)

TIBRIC. An old name for the coal-fish.

TIBURON [Sp.] The shark.

TICKET. An official warrant of discharge, so that a heavy penalty
attaches to the loss of any of the blank ones in the captain's charge.
It is always used in counterparts, which are ordered to be perfect
duplicates of each other.

TICKET-BOOK. A register for accounting for all tickets and certificates
received and used.

TICKLING OF FISH. The same as _gennelin_. (_See_ GROPING.)

TIDAL WAVE. The wave caused by the combined action of the sun and moon:
its greatest influence is felt some time after the moon has passed the
meridian of any place.

TIDE. A regular periodical current of waters, setting alternately in a
flux and reflux; it is owing to the attraction of the sun and moon, but
chiefly to the latter. The highest as well as most rapid, perhaps, are
in the Gulf of Fundy and the river Wye; and on the contrary the lowest,
as well as feeblest, are in the Mediterranean generally.--_To tide_, is
to work up or down a river or harbour, with a fair tide in a head wind
or a calm; coming to anchor when the tide turns.

TIDE OR TIDAL HARBOUR. A port which can only be entered at a certain
time of flood.

TIDE AND HALF-TIDE. Those roadsteads affected by several rivers or
channels leading into them; as, for instance, Spithead.

TIDE-BALL. A ball hoisted to denote when the depth of water permits
vessels to enter a bar-harbour, or to take the bar outside, from the
known depth within.

TIDE-GATE. A place where the tide runs strong.

TIDE-GAUGE. An instrument contrived for measuring the height of the
tides.

TIDE, EBB OF. The falling tide.

TIDE-POOL. A sort of