Sailboats work like a big raft that doesn't need oars . it is not a physical object to walk on. you need to sit in the right hand stern seat to move it (it highlights like blocks outlines if you have that active. the stern is the opposite end to the mast.) it's easier to see if you build a dock or platform the stand right beside it.
Reed chests, Clay Storage pots and/or Single wooden chests can be placed in any of the 8 central slots by holding ctrl + a right click, like a raft. Shift click quick inventory placing doesn't work properly for shipboard chests so you have to drag them over manually. It does oddly work for retrieval though.
To place an elk mount (if you have one) in the ship you need to put a wooden fence post in one of the chest slots towards the Prow (front, sail side) and leave two open storage slots aft of it (towards the stern, captain seat side). use the lead rope and right click the fence post to let the elk in or out.
Variation of this: Elk(E), Chest(C), Fencepost(F)
Stern - C C C C - Prow
Capt. - E E F C - Prow