| A | B
| C | D | E
| F | G | H
| I | J | K
| L M | N | O | P | Q | R | S | T | U | V | W | Y |
|
| JACK | A common term for the jack-cross-trees. (See UNION.) |
| JACK-BLOCK | A block used in sending topgallant masts up and down. |
| JACK-CROSS-TREES | Iron cross-trees at the head of long topgallant masts. |
| JACK-STAFF | A short staff, raised at the bowsprit cap, upon which the Union Jack is hoisted. |
| JACK-STAYS | Ropes stretched taut along a yard to bend the head of the sail to. Also, long strips of wood or iron, used now for the same purpose. |
| JACK-SCREW | A purchase, used for stowing cotton. |
| JACOB'S LADDER | A ladder made of rope, with wooden steps. |
| JAWS | The inner ends of booms or gaffs, hollowed in. |
| JEERS | Tackles for hoisting the lower yards. |
| JEWEL-BLOCKS | Single blocks at the yard-arms, through which the studdingsail halyards lead. |
| JIB | A triangular sail set on a stay, forward.
Flying jib sets outside of the jib; and the jib-o'-jib outside of that. |
| JIB-BOOM | The boom, rigged out beyond the bowsprit, to which the tack of the jib is lashed. |
| JIGGER | A small tackle, used about decks or aloft. |
| JOLLY-BOAT | A small boat, usually hoisted at the stern. |
| JUNK | Condemned rope, cut up and used for making mats, swabs, oakum, &c. |
| JURY-MAST | A temporary mast, rigged at sea, in place of one lost. |
| A | B
| C | D | E
| F | G | H
| I | J | K
| L M | N | O | P | Q | R | S | T | U | V | W | Y |