Max Engine for 25' Sailboat?

florida newbie · 16-06-2009, 01:09

what is the largest engine you can put on a 25 ft sail boat and what is the horse power / mph conversion rate? thanks.

Portobello · 16-06-2009, 01:20

Planing hull or displacement? Inboard or outboard? There are a lot of variables Florida. Look at like boats and see what they have. I had a 25 footer with an 18 hp diesel and that went really well - displacement hull fixed keel though.

jjt · 16-06-2009, 03:24

In a sailboat: 4HP each 1000 Kg of displacement
That is the minimun. I'll would add a 10% over that figure

Chief Engineer · 16-06-2009, 20:27

if the waterline length is 25 feet...the fastest that you are going to go is 6.7 knots
doesn't matter how big an engine you put in it

GordMay · 17-06-2009, 05:37

One oft-quoted (Yanmar, Westerbeke, etc) rule of thumb for Horsepower Required (Displacement Hull):
One horsepower per 500 pounds (± 50lb) of displacement (4 HP/Ton) for coastal cruising
and
1.25 hp per 500 lb (± 50lb) of displacement (5HP/Ton) for offshore work .

Remember, most HP/Displ. calculations utilize “Propeller Horsepower”, which might be as low as ½ Brake (Engine) HP.

SkiprJohn · 17-06-2009, 12:29

Aloha Florida,
My Catalina 22 had a 6hp Johnson. That was more than I needed. I just sailed interisland on a Columbia 28 with a Honda 7.5. The 2 cycle engines are lighter and easier to handle and will not weigh down your stern as much as the 4 cycles. The 4 cycle engines are more economical and last longer. You don't need more than 10hp on your 25 and I'd go for a 7 to 8 hp.
Good luck in your choice.
Kind regards,
JohnL

florida newbie · 17-06-2009, 15:52

Thanks all, your great!

essencevictoria · 24-06-2009, 20:00

Quote:

Originally Posted by florida newbie

what is the largest engine you can put on a 25 ft sail boat and what is the horse power / mph conversion rate? thanks.

I have a 1981 Catalina 38 ( #109 ) and have to repower as the transmission has seized and I feel it is not fiscally wise to add a new transmission to an old, corroding engine.
I am considering a Beta engine to replace my Universal 2524 ( 24 HP).
Would a 35HP Beta ( rather than the 28) be overkill on the old Catalina?
And I would appreciate any comments on the Beta engine!

Thanks ...

Paul of "Waltzing Matilda"

cal40john · 24-06-2009, 22:23

Quote:

Originally Posted by florida newbie

what is the largest engine you can put on a 25 ft sail boat and what is the horse power / mph conversion rate? thanks.

Just one foot longer and you could put a 60 hp engine on it.

POWERING AND SKIING

John

mesquaukee · 25-06-2009, 20:25

A friend of mine has a Cape Dory 30 with a 22 hp engine. It pushes it around just fine.
One day he was going out through a pass in the barrier reef in Belize. Took him 10 minutes to go a couple of hundred feet. He forgot to dog down his forward hatch. He watched the water filling his boat for 10 long minutes as he could not turn or leave the tiller.
In short heavy seas you need a lot more power and a matching prop. It all depends on where you want to go.

16-06-2009, 01:20	#2
Portobello Registered User Join Date: Mar 2009 Location: Hobart Boat: Portobello - a Walter Knoop designed "DOVEN 30" Posts: 167 Images: 4	Planing hull or displacement? Inboard or outboard? There are a lot of variables Florida. Look at like boats and see what they have. I had a 25 footer with an 18 hp diesel and that went really well - displacement hull fixed keel though. __________________ Love the journey!

16-06-2009, 03:24	#3
jjt Registered User Join Date: Jul 2006 Location: Buenos Aires, Argentina Boat: Pandora 32 - Zingara Posts: 26	In a sailboat: 4HP each 1000 Kg of displacement That is the minimun. I'll would add a 10% over that figure __________________ A ship should not sail with just one anchor, neither the life with a single hope. - Epicteto de Frigia

17-06-2009, 05:37	#5
GordMay CF Adviser Join Date: Mar 2003 Location: Thunder Bay, Ontario - 48-29N x 89-20W Boat: C.L.O.D. (Cruiser Living On Dirt) Posts: 13,478 Images: 233	One oft-quoted (Yanmar, Westerbeke, etc) rule of thumb for Horsepower Required (Displacement Hull): One horsepower per 500 pounds (± 50lb) of displacement (4 HP/Ton) for coastal cruising and 1.25 hp per 500 lb (± 50lb) of displacement (5HP/Ton) for offshore work . Remember, most HP/Displ. calculations utilize “Propeller Horsepower”, which might be as low as ½ Brake (Engine) HP. __________________ Gord May ~~_/)_~~ (Gord & Maggie - s/v"Southbound") "If you didn't have time/$ to do it right in the first place, when will you get the time/$ to fix it?" Custom Search CF ➥ http://www.google.com/cse/home?cx=01...%3A2lb6ozabif0

Thread Tools
Show Printable Version Email this Page
Display Modes	Rate This Thread
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode	Rate This Thread:

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
ICW - Virginia to NC - 25' sailboat and ?HP	mow2000	Atlantic Ocean & the Caribbean	15	10-09-2008 04:58
Santana 25'	ccmumbo	Monohull Sailboats	6	23-10-2005 18:31

16-06-2009, 01:09	#1
florida newbie Registered User Join Date: Jun 2009 Posts: 15	Max Engine for 25' Sailboat? what is the largest engine you can put on a 25 ft sail boat and what is the horse power / mph conversion rate? thanks.

16-06-2009, 20:27	#4
Chief Engineer Commercial Vendor Join Date: Aug 2006 Location: North of Baltimore Boat: Ericson 27 & 18' Herrmann Catboat Posts: 2,408	if the waterline length is 25 feet...the fastest that you are going to go is 6.7 knots doesn't matter how big an engine you put in it

17-06-2009, 12:29	#6
SkiprJohn Registered User Join Date: May 2006 Location: Kea'au, Big Island, Hawaii Boat: Cascade, Cutter, 42 - "Casual" Posts: 5,552	Aloha Florida, My Catalina 22 had a 6hp Johnson. That was more than I needed. I just sailed interisland on a Columbia 28 with a Honda 7.5. The 2 cycle engines are lighter and easier to handle and will not weigh down your stern as much as the 4 cycles. The 4 cycle engines are more economical and last longer. You don't need more than 10hp on your 25 and I'd go for a 7 to 8 hp. Good luck in your choice. Kind regards, JohnL

17-06-2009, 15:52	#7
florida newbie Registered User Join Date: Jun 2009 Posts: 15	Thanks all, your great!

25-06-2009, 20:25	#10
mesquaukee Registered User Join Date: Jun 2009 Location: Western Caribbean & ocassionaly inCanada Boat: Mesqua Ukee, Buccaneer 40 (Salar 40) Posts: 465	A friend of mine has a Cape Dory 30 with a 22 hp engine. It pushes it around just fine. One day he was going out through a pass in the barrier reef in Belize. Took him 10 minutes to go a couple of hundred feet. He forgot to dog down his forward hatch. He watched the water filling his boat for 10 long minutes as he could not turn or leave the tiller. In short heavy seas you need a lot more power and a matching prop. It all depends on where you want to go.