How many MPH does my boat go?

Question

I have about a 30 year old boat with a 15 year old 70HP motor...it is fairly small that seats 4 comfortably(It says it seats 8 though cause the seats fold down. I use it on my lake. It is not a bowrider. I need to know because I want to know if my son(130 pounds) Could barefoot water ski behind it. It does not have a speedometer. PLEASE HELP.

Answer 1

I have a fairly cheap handheld GPS that will tell u speed. Find one and take it for a ride. You might need to reprop your boat down one or two pitches for the hole shot you would need.

Answer 2

I pulled a 155 pound friend on my open bow Invader 4 cylinder at arounnd 35 (handheld G.P.S.) and he barefooted 4 seconds. Don't know if it was just too slow or was not used to barefooting. He did the slolam and kick the ski thing. I believe you need faster speeds like 42 and a decent operator . According to wilkipedia though a 150 pounder should need 35 to ski
Formula (lb) Divided by 10 +20 =boat speed
150lb person divided by10 (15) +20 =35

Answer 3

Try it an see 70 hp not much power for barefooten?An how fast does it come up on plain. Might have to drop a pitch on the prop for more power??