The trans fluid is easy, Dextron ATF. The Motor oil on the other hand gets interesting, poll 10 "experts" & you will get 10 different reccomendations of what type & when to change. Our boats have very different loads & use than todays modern automobile. Here is my opinion this week on oils:
1) Synthetics are superior lubricants particularly under high internal heat conditions, our boats run "cold" compared to modern cars
2) Modern cars call for very "light" oils (0-20 example) primarily to squeeze a little better MPGs, our boats don't fall into this category
3) The Indmar Owners manual for your boat calls for SAE30 oil changed every 50 hours or 60 days whichever comes first
4) I use SAE 10-40 (non syn) + STP in my boats & it gets changed every season