What needs to be agreed upon?

1. Legal paperwork , as in who exactly are the partners and who is listed on the Documentation, title, Bill of Sale, etc. A consideration of this would be whether the partnership is a legal entity, such as a corporation, or whether it remains owned by the individuals. There are advantages and disadvantages to both avenues. Review each option carefully.
2. Insurance , such as in the coverage amount, area, and deductible, while also insuring that all partners are considered. Everyone involved needs to be in agreement, as well as fully informed on the coverage. This will also probably determine rules of usage; like whether the boat can be chartered to a non-partner. Or whether a partner's family, or friend(s) can use the boat without the partner onboard. Or, can the boat only be driven under the supervision of a USCG Captain certified to the size of your vessel?
3. Dockage , as in where the vessel will be stored and how much will this storage cost. Will the boat be in dry dock, or stored in the water? Will it spend six months in Florida and six months in New York?
4. Maintenance and upkeep , as in what will be done by the partners. This includes cleaning and basic maintenance. Also, what will be done by outside contractors? This should also cover any damage that may be caused by a partner. Is the guilty party responsible for all damages on his or her voyage? Or does the partnership absorb all losses because all three owners are clumsy?
5. Vessel rules - for example: How many people are allowed onboard and whether pets can be brought along. Where can the vessel be taken? Does one partner need the permission of the others to take it out of US waters?
6. The purchase of equipment and gear . Do all agree on the purchase of a particular toy? For example, one party would like the vessel equipped with a personal watercraft, two complete sets of dive gear and an air compressor to fill SCUBA tanks. The other wants a fully stocked bar at all times. Are these extras absorbed in the partnership, or is each owner responsible for providing the extra frills?
7. How to deal with a partner that wants to sell their share, or can not continue to maintain their share. This could be the most important contingency plan of all. What happens when one party either can no longer afford their share, or simply no longer wants to participate? What happens in the event of an untimely death to one of the owners? A serious illness could not only be costly from the standpoint of medical expenses, but also from the possibility of lost earnings. Do you try to keep the partnership alive at this point or is the boat to be sold? Be sure to think of this endeavor long term!
8. The existence of a "slush/contingency" fund to cover items not previously considered, as well as emergencies. If you keep a vessel anywhere along the Eastern Seaboard of the United States, there is always the possibility of a hurricane. The existence of such a fund could provide for the removal of a vessel from the water into a safer storage facility, thus saving the vessel from damage or destruction.