Re: 25" vs. 20" shaft advantages/performance difference?
Shaft length depends on the transom height of the boat.<br /><br />Most boats are designed to run standard outboard shaft lengths of 15", 20", 25", and 30". You can measure the distance from the bottom of the hull to where the outboard rests on the transom to determine the shaft length you need (round up), or check with the manufacturer of the boat.<br /><br />A longer than necessary shaft (say a 25" on a 20" transom) will always work, but not give good performance (because of excess drag). But a 20" shaft will not work on a 25" transom, etc. due to cavitation problems. Your best bet is to match them.<br /><br />I can't stand sea-drive transoms or short transoms. I hate it when waves come over the back of the outboard or over the transom. And I don't enjoy fishing over sea-drives. So with an offshore boat I prefer the tallest transom and longest shaft possible. A 23' CC probably uses a 25" transom.
