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Thread: Outboard Power for an 8M?

  1. #1

    Cool Outboard Power for an 8M?

    I just purchased a 8M and it has a 40hp 4 stroke merc. Is this too much power? Would like to hear from anyone with an outboard. I'm thinking 18 hp 2 stroke for my boat. Fair winds and following seas.
    Woody

  2. #2

    Default Re: Outboard Power for an 8M?

    Quote Originally Posted by Boatnutwoody View Post
    I just purchased a 8M and it has a 40hp 4 stroke merc. Is this too much power? Would like to hear from anyone with an outboard. I'm thinking 18 hp 2 stroke for my boat. Fair winds and following seas.
    Woody
    I have had my 8M for 14 years now. Initially it had a 15HP 4 stroke Honda that was ok but I thought it lacked power (struggled to get over 6 knots) and it was only a long stroke and neaded to be Ultra long shaft to avoid coming out of the water in lumpy conditions. I fitted a 30hp Tohatsu 2 stroke with an Ultra long (27") shaft and that was very good if a bit thirsty when using real power. That would touch 7.8 knots in flat water and a clean bottom. However the availablity of waterside petrol was an issue (NW uk and Wales) and I wanted to have a longer range with the 2x5gallon in the s/b rear cockpit locker and the 2x5 gallon spare cans I carry in the port side foredeck locker. I also really fancied power tilt so as to be able to sail for short periods with the leg up. With a manual tilt I tended to motor sometimes when the wind was variable as lowering the leg was a pffaff. After about 5 years with the 30hp 2 stroke I got a new 4 stroke Tohatsu 20HP with Ultra long leg and power tilt. This has run without fault for 5 years and is a good compromise between power and fuel consumption. I average about 0.6 galls per hour at 5.5kn and it will touch 7.4 kn in flat water. The power tilt is great and a real help to sailing more and better. The two 5 gallon tanks with a 2 way fuel tap works very well as I am always aware of the fuel situation due to switching tanks etc. The 20 hp engine is also not too big to swivel in the event that outboard streering in linked to the rudder bar.
    What sail number is your 8m? Good luck with your 8M we love ours.

  3. #3
    Join Date
    Feb 2009
    Location
    Belgium
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    Default Re: Outboard Power for an 8M?

    On my 8M, I have a 15hp 4stroke longshaft and I conform the above... It is maybe just short in power and can lift out in a big swell. If possible, look for low geared outboard, high thrust prop and ultra long shaft...
    1979 Catalac 8M - 8-84 - Galu'Lati Go

  4. #4

    Default Re: Outboard Power for an 8M?

    I do not think that 40hp is too much power for a 8M just too heavy (I am not sure how you could trim properly with that weight other than have midships water tanks) and far too thirsty for a cruising boat. 25hp would be the optimum but you cannot get an Ultra long Shaft (27") in a modern 4 stroke 35. (Tohatsu did a 30hp 2 stroke). When I bought my 20hp Tohatsu in 2012 20hp was the biggest hp that they did in Ultra long shaft and I do not think any of the other makers do the ultra long in other than 9.9. You used to be able to get an ulltra long Bigfoot Mercury or Mariner in the 30hp but not anymore, I think.
    An 18hp 2 stroke has the light weight and is plenty of power but you will be pushed to find a ultra long shaft one. They do sell 2 new strokes in Jersey (Mainbrayce Marine) and you may get an ultra long shaft one from them, but not sure where you are located?

  5. #5

    Default Re: Outboard Power for an 8M?

    I forgot to say I just fitted a 4 blade hight thrust prop this weekend. I only motored 1/2 mile with a heavily fouled bottom so I am not sure how much better it is going forward BUT it is amazingly better going astern/stopping. Solas claim 60% more thrust astern due to the symetrical blade profile and I can well believe that.

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