Engine Size Question

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tekneak

I have a '76 Macgregor Ventura 21: I have only sailed for a few years, my 5hp motor died and I have a 20hp (weighing around 125lbs) and was curious if this would work, my concern is it will crack the rear of the boat or the thrust may damage the housing? I just really dont know if this would be a good idea or not, someone please help me if you know anything about this. Thanks in advance.
 
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Ross

it is certainly overkill but you don't have to use all of that hp.

If you have a 300 horse power car you best not use more than about 75-100 if you don't want moving violation tickets.
 
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Nice N Easy

Too much motor

Think that would be too much motor, too much weight. Thats a pretty heavy motor to be hanging off the back of a 21er. Would possibly damage the transom, but you can be sure it would certainly make the boat sail like s*#^.
 
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CharlieCobra

Agree with the previous

I had a 9.9 Evinrude, which is the largest advised for the V-21 on mine. She sails much better and still motors at 6 knots with a 3.5 Tohatsu.
 
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tekneak

Thanks

thanks for the help guys, i guess i'll have to wait a while to get my motor fixed, kind of need it to get around the inlet better....i appreciate it a bunch
 
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Jim

You would have to reinforce the trasom and it is not

worth it. That engine is to big for the boat. I would get a 5 to 9.9 HP if you sail where there is current. 3.5 IS UNDERPOWER UNLESS YOU RACE OR ARE ON A LAKE.
 
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Joseph Shirley

Ross' comment is correct here

The motor is an overkill, but your transom will support the weight, but it probably will not support the torque if you crank it up. If however you use it with some common sense an run it so you don't exceed the speed you used to go at with your old motor you should be all right.
The others are correct also in that your boat should sail better with less weight hanging on the transom. So if you do use it so you can go sailing while you go and get another motor thats OK, but you should be looking for a smaller motor.

Have fun

Joe S
 
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Timo42

Take a look at how thin the transom is

before you think about hanging that heavy a motor on it, especially on an adjustable bracket, you have 1/4" of fiberglass with a 1/2" plywood reinforcement glassed in thats about 1 square foot. I am in the process of glassing in a reinforcement just to hang a swim ladder, and will probably put a layer across the whole transom just because. Tim
 
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bffatcat

Outboard size

about 2hp per 1000 lbs of displacement should do it anything bigger is overkill
 
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oldiesrocker2001

Maybe too heavy

While I glued on an additional 3/8 laminated board inside the transom before bolting on the new adjustable mount, I kept to a 4HP at about 57 or so pounds. I found that the boat doesn't point too well with too much weight on the stern either. I'd go with 9.9 hp max if it were me(and since every time this relatively new Merc of mine is needed there's something wrong, It may be me sooner rather than later).
 
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