Banks can Insure a specific ship if it ever gets plundered.
Example:
Sir Henry Morgan insures CJ's lvl 10 MoW.
lvl 10 MoW = 28mil gc.
Insurance = 250,000 gc per day to SHM.
If Ship is Plundered, all expenses are paid in gold by SHM, and the ship can be picked up by CJ during the next 3 weeks. If CJ does not pickup his MoW, all the gc goes back to SHM.
Penalties can exist, such as: Lose the ship, 10% increase in insurance costs + player cannot cancel the insurance until he/she pays back the entire ship worth through the insurance.