[Fr. Frank]

A 115 will power the 20' ok. My grandfather's 20' Seafari came new from the dealer with a Chrysler 105, which really only put out about 95 hp at the prop. It had a top speed of about 27-28 mph, but it got on plane fairly easily. A new 115 4S EFI should push the 20' into the low to mid 30's at WFO, and cruise at 23-25 mph.

My '72 20' Seafari has a '91 150 hp Merc 2S carb model, reman and balanced in '02, with 200 carbs, and dyno'd at 185+ hp at the propshaft. I have a top speed of about 50 mph at 6100 rpm, I cruise at 4000 rpm and about 34 mph. And that's with Slickkote bottom paint I plan to sand and paint the bottom again this summer. Even though its Slickkote, I'm sure I lose a couple of MPH due to the paint. But I leave it in the water twice every year for a 10-14 day stretch.

There's a red 20' Seafari here in the Crystal River area I see from time to time. I think he said it's a '79 model. He's got an 2004 Suzuki 200hp 2S on the back running a PowerTech 4 blade 21P prop. We ran them up one day just for fun in Ozello Bay, and when I was trimmed up and WFO, running at 51 mph on the GPS, he had at least 3 mph more than I did. He claimed he was doing 60 on his speedometer, but I think he was more like 54-55 mph. He has no bottom paint and his hull is clean and buffed. VERY nice boat. It looks almost brand new inside and out. (Mine just looks old and well loved and used.)

I use a PowerTech prop as well. (PowerTech Propellors) I run a one-of-a-kind custom-built 15.5" diameter by 16.5"P progressive rake 3 blade made by the same company. The blades are very heavy, and I have less than 1/4" clearance between the tips and the cavitation plate. The extra diameter combined with lower pitch and progressive rake change gives me the hole shot and low-mid speed torque application I want at the sacrifice of a little top speed.