So it sounds like the easiest solution to your situation is to trigger the dialog when the player enters a trigger near the boat, so the dialog happens without the player interacting with it.

The scripting call to make the dialog happen is Proc_StartDialog:
Code
Proc_StartDialog((INTEGER)_Automated,(STRING)_Dialog,(GUIDSTRING)_Speaker1,(GUIDSTRING)_Speaker2)

Here's an example rule:
Code
IF
CharacterEnteredTrigger(_Player, TRIGGERGUID_S_MonkWorks_BoatDialog_1266a4cf-f736-49a0-a76c-e56b8a99a0d1)
AND
CharacterIsPlayer(_Player, 1)
THEN
Proc_StartDialog(0, "MonkWorks_BoatDialog", ITEMGUID_S_MonkWorks_Boat_000_e4c53f08-674b-4483-a358-30b33e586873, _Player);

Notice how the boat is first in the proc, followed by the player. This assumes that the boat is the first speaker group in the dialog, and the player is the second (as is standard for dialogs).

Alternatively, you could trigger this dialog when a character interacts with the boat:
Code
IF
CharacterUsedItem(_Player, ITEMGUID_S_MonkWorks_Boat_000_e4c53f08-674b-4483-a358-30b33e586873)
THEN
Proc_StartDialog(0, "MonkWorks_BoatDialog", ITEMGUID_S_MonkWorks_Boat_000_e4c53f08-674b-4483-a358-30b33e586873, _Player);

LaughingLeader's DOS2 Mods