Will a M25 motor push a C28mkll faster than a M20? of course it will but how much faster? Is it worth the extra fuel? Does anyone have any accurate comparisons between these motors in a 28. Hull speed is 6.5 can either motor cruise at this speed? Don't hold back, tell us how fast you go under power. Thanks
how much hp is enough
- Thread starter John C
- Start date
- Status
Engines and Speed
John The M25 has been used in C30s and C34s and C36s. They're all a bit to a lot heavier than a C28. The 21 hp has been fine in our '86 C34. Once you get past hull speed, you're just pushing a lot of water for a lot more fuel. Fuel consumption is less than 1/2 gallon per hour, so it's not an issue. You can't go wrong with either engine. Stu
John The M25 has been used in C30s and C34s and C36s. They're all a bit to a lot heavier than a C28. The 21 hp has been fine in our '86 C34. Once you get past hull speed, you're just pushing a lot of water for a lot more fuel. Fuel consumption is less than 1/2 gallon per hour, so it's not an issue. You can't go wrong with either engine. Stu
what's your hurry?
I wouldn't get carried away, my 24hp moves my 38 just fine. Is the extra cost, fuel comsumption, ect really worth a hair more speed? Its a sailboat, it's slow no matter what you do. Of course if you want to be able to go above hull speed into a gale...
I wouldn't get carried away, my 24hp moves my 38 just fine. Is the extra cost, fuel comsumption, ect really worth a hair more speed? Its a sailboat, it's slow no matter what you do. Of course if you want to be able to go above hull speed into a gale...
M3-20 in a Mk I
The accepted formula for HP/displacement is 2hp per each thousand lbs of displacement, which would make the 18hp M3-20 perfectly adequate. Anything more than that is considered a waste of power and fuel. The c28 MkI came with a Universal 18hp. Virtually identical MKII models up to around 2003 came with the Universal M25XP, 23 hp, followed by the most recent C28s with the 26hp version of the same engine. The downside of the bigger engines is the additional weight, anywhere from 50 to 70 pounds more than the 18hp. If sailing performance is important, this becomes an issue. I have the M3-20 with a slightly higher pitched two-blade prop than recommended that easily cruises at around 6kts@2800 rpm. With a clean bottom at full throttle the boat reaches 6.8kts and actually planes a bit, rolling side to side. Good question, though, because that motor is as important as the sails, IMHO.
The accepted formula for HP/displacement is 2hp per each thousand lbs of displacement, which would make the 18hp M3-20 perfectly adequate. Anything more than that is considered a waste of power and fuel. The c28 MkI came with a Universal 18hp. Virtually identical MKII models up to around 2003 came with the Universal M25XP, 23 hp, followed by the most recent C28s with the 26hp version of the same engine. The downside of the bigger engines is the additional weight, anywhere from 50 to 70 pounds more than the 18hp. If sailing performance is important, this becomes an issue. I have the M3-20 with a slightly higher pitched two-blade prop than recommended that easily cruises at around 6kts@2800 rpm. With a clean bottom at full throttle the boat reaches 6.8kts and actually planes a bit, rolling side to side. Good question, though, because that motor is as important as the sails, IMHO.
M3-20
The M3-20 will push my Catalina 30 along at hull speed wit ease. Hard to justify the added wweight and expense for the 25.
The M3-20 will push my Catalina 30 along at hull speed wit ease. Hard to justify the added wweight and expense for the 25.
- Status