In addition, the ship carried a small square sail, a spritsail, on the bowsprit.
From the en.wikipedia.org
The spritsail is a form of three or four-sided, fore-aft sail and its rig.
From the en.wikipedia.org
Topsails were added by 1460, then a spritsail under a bowsprit.
From the en.wikipedia.org
The spritsail rig was normally used without a boom.
From the en.wikipedia.org
The spritsail was best known from its use in the Thames sailing barge, which employs two similarly sized spars to form the framework for the sail area.
From the en.wikipedia.org
It's sheltered but the gentlest breeze is all that is necessary to send our long pulling boat with its little spritsail effortlessly across and out of the bay.
From the nzherald.co.nz
More examples
A fore-and-aft sail extended by a sprit
The spritsail is a form of three or four-sided, fore-aft sail and its rig. Unlike the gaff where the head hangs from a spar along its edge, this rig supports the leech of the sail by means of a spar or spars named a sprit. ...
A sail attached to a yard which hangs under the bowsprit, and has a large hole at each of its lower corners to evacuate the water which fills its cavity by the surge of the sea when the ship pitches.
A four-sided fore and aft sail set on the mast, and supported by a spar from the mast diagonally to the peak of the sail.This is a time-honoured contrivance for setting a sail that has no boom, but a gaff is preferred if the sail has a boom.