I sold boats for a dealer in North Atlanta and can offer my experience. I do know boat manufacturers maintain "territory". We, for instance, were the MasterCraft dealer for all of Georgia. MasterCraft protected us well by requiring dealers elsewhere selling to buyers with residence in Georgia a percentage.
Before you do anything in life for income, WORK in the industry FIRST. It is difficult to establish a "boat dealership" due to requirements. If you are an individual your personal "finances" will be the beginning "factor". You will need to offer a "service department" as well.
Easiest way, and you can make a lot of money, "used boat business". This will be the beginning of establishing a successful dealership to possibly become a "new" boat dealer in the future.
Manufacturers want to see numbers, YOUR sales. As in any sales job a "quota" will be assigned for you to purchase boats to sell. In addition, you will need to purchase trailers as well. Trailers for new boats are designed for that boat.
PWC manufacturers seem to sell to anyone with the money to purchase in quantity. They do assign a "quota" as well. Other requirements may factor as well.
I can, from experience in the business, NEW boat sales is a tough business. "Margins" are NOT all that great to offer good pricing buyers will accept. NO matter what "brand" of boat you sell "competitive" boats are numerous. Not only establishing contact for "new" boats, but YOU must establish relationships with "lenders" and banks for financing to buyers. Insurance can be costly as well.
This info is what I learned by selling for a dealer. You must understand as well the "seasons" to sell. Boat dealers earn 40% + of their "annual " profits at "boat shows" early in the year, usually beginning in January. Buyers will continue through the beginning of summer. Through summer months it is "slow" and does not really "pick up" again till early winter, this "time frame" buyers can get a deal.
Dealers in this business are like a "community". Everyone knows each other due to the many "boat shows" all attend. You are in competition but there will be times you need to call to help a customer. It could be for a boat you recommend not on your lot or for service. Remember, this is a business that also depends on referral business and any assistance for a client will be rewarded by referred customers.
Hope this helps, Good Luck.
Sold boats in North Atlanta for years.