Re: Starting from scratch Mercury 115 Glastron SSV167
'80 Merc 115 (power head rated) translates to roughly 115 x .90 = roughly 100 hp in post '84 engines which are prop rated...just to put things in current perspective. Gearbox is 2:1. Makes a difference on prop pitch selection. I ran a 21P SS Laser I on my boat of similar size with a 115 prop rated Tower, and for what it was it was fine.
My guess for you would be a SS 19P and ported....aka Laser II. The 19 would give you a good top end and the ports (holes in the side of the prop which can be adjusted with plugs for the desired amount of hole shot slip) would make for a stellar hole shot with a good boat load of stuff. If you want to run a lot of water toys, slalom ski, and all, with the boat full of people and gear (stuff) then I'd drop down to the 17 SS. Don't worry about the exact diameter of the 13" prop. That varies with the design of the individual prop. A tach really helps get it right and that engine should run at 5500 rpm at WOT with your normal load; that's how you set it up. Everything else falls in place as the rpms are varied between idle and WOT.
Ports on the Laser come in varying diameters. The ports deliberately introduce exhaust gasses over the prop blades thus unloading the solid water that would be there otherwise and in doing so allows the engine to get it's rpms much faster and rpm's mean usable horsepower. The idea is to use as large a hole as you can that provides you the best hole shot but doesn't blow out too badly in rough water. The ports really are a boon when water skiing. It helps your skier to get up fast which makes for a novice being successful at the sport whereby a long drawn out launch (of the skier) would cause them to fall off, or just let go and ultimately fail. BTDT
When up and running at the higher engine rpm's the ports will automatically seal, the engine will drop rpms (pick up the extra load of solid water) and the speed will increase a few mph. Sounds and feels really cool when it does it.
My 2c,
Mark