How much horse power do i need for yacht?

S

stonedpirate

Recruit
Joined
Jun 9, 2011
Messages
2
Hi,

I have a small 20' trailer sailer that weights about 700kg loaded.

It currently has an old 5hp 2 stroke outboard and it does the job.

If I wanted a new 4stroke, would 5hp be enough? Or do i need to double it?

The thing is, in my country you dont need a licence for boats under 6HP so i am hoping to get away with a small 4stroke.

Thanks
 
ezmobee

ezmobee

Supreme Mariner
Joined
Mar 26, 2007
Messages
23,767
Re: How much horse power do i need for yacht?

I wouldn't think a 5 would do you much good if there was any wind in your way. I'd want a high thrust 9.9 minimum or preferably a 15 for that 20'.
 
W

Whoopbass

Senior Chief Petty Officer
Joined
Jun 29, 2006
Messages
650
Re: How much horse power do i need for yacht?

A new 5hp 4-stroke will have more power then an older 2-stroke of the same hp simply because its newer.
 
ezmobee

ezmobee

Supreme Mariner
Joined
Mar 26, 2007
Messages
23,767
Re: How much horse power do i need for yacht?

Whoopbass said:
A new 5hp 4-stroke will have more power then an older 2-stroke of the same hp simply because its newer.
Click to expand...

Not appreciably and it will also be loads heavier.
 
SolingSailor

SolingSailor

Petty Officer 2nd Class
Joined
Dec 24, 2009
Messages
197
Re: How much horse power do i need for yacht?

In my opinion, 5 hp will be enough. Here's another consideration: The higher power motors are propped with a higher pitch for higher speed. Top speed on your displacement sailboat is limited by its waterline length to probably around 5 knots or less. Even for punching into waves, the extra power is wasted, and will result in cavitation with the higher pitched prop. It may be possible to find a lower pitched prop for the bigger motor, but I think the choices are limited in the smaller sizes.
 
nwcove

nwcove

Admiral
Joined
May 16, 2011
Messages
6,293
Re: How much horse power do i need for yacht?

ezmobee said:
I wouldn't think a 5 would do you much good if there was any wind in your way. I'd want a high thrust 9.9 minimum or preferably a 15 for that 20'.
Click to expand...

i have never been on a sail boat, but i agree. in certain situations, 5 hp isnt much to fight against a strong crosswind in a narrow channel. take the safe boating course, up your horsepower (unless the mount isnt rated for it!) .......no replacement for displacement!
 
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