Single engine/twin engine prop slip/speed
 

Was talking to a buddy today and we were talking speed/vs props and I had a question that even through google searching I couldn't find a real answer to.
I understand How prop pitch, rpm, gear ratio and slip calculate your actual speed but here's my question. Does having twin engines change that speed number?

For example a single 24v bottom non step with a 23p 3 blade with a 1.5 ratio spinning to 5300 and 10 percent slip is gonna run around 70 (69.25) I know the slip number could be better but this is just for arguments sake.

Now say we have a 31v bottom non step twin engine with 23 3 blades, 1.5 ratio spinning 5300 and 10 percent slip would it also run 70? Or run faster? More weight to move, but maybe less drag? I've never seen a prop slip calculator for twin engines is there one?

Just curious.

I talked to Brett @ BBlades a couple of yrs ago about some props for my Kachina, we went through the #s and he didn't say anything about a different formula for single or twin engine boats. I will be talking to him again when I finish testing the props I have now. I will ask but I think they would ask how many engines in the calculator app if there was a difference. Randy

That's what I was thinking, I've looked at most the prop calculators on every site, I look at it as a prop can only push the amount of water that the pitch/diameter will allow... But at the same time having two would push more water then 1 you'd think. I can see both ways making some sense. Thanks for the response.

This is a question I have often wondered about myself.