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Max Horsepower Rating 20 ft sailboat

Feb 5, 2009
251
Gloucester 20 Kanawha River, Winfield, WV
The reason I recommended a 6HP engine over a 4HP is that for most manufacturers 4,5 and 6 HP are the same engine (size and weight) but with a different carburetor and a higher degree of tuning. Obviously the 6HP will cost more but the extra power may come in handy in foul weather.
Good point. Modern 4-6hp outboards are typically all around 60 pounds. (My old Evinrude is 38.)
WRT tides and currents, I may be wrong, but I've always assumed hull speed doesn't care whether it's the boat or the water that's moving.
 
Jun 8, 2004
8,885
-na -NA Anywhere USA
Previously I mentioned owning an RK 20. It was my first sailboat years ago sailing at Smith Mt lake and the Chesapeake Bay. A 5 hp served well. If ever sailing with the cast iron keel up particularly in the Bay, knowing the construction, I had major concern should the up haul line ever break, I know major damage would occur which is why I left it down. The only time bringing it up if I ran aground or for launching/retrieving from the trailer. I learned a lot from that boat. Later I became a Sailboat dealer with emphasis on small boats representing Beneteau, Catalina, Hunter, MacGregor, Com Pac, Precision and a few others. The RK 20 gave me alot of knowledge to help me to design a boat or two
 
Oct 22, 2014
16,101
CAL 35 Cruiser moored EVERETT WA
I've always assumed hull speed doesn't care whether it's the boat or the water that's moving.
This would be true. Hull speed is Hull speed. What is affected is upon reaching hull speed you are theoretically going thru the water as fast as you can. Looking out on the nearby rocks you may find yourself standing still, rushing towards them or backing away from them. Then it can become painfully important.
 
Sep 8, 2020
45
Merit 22 Honker Bay
It was interesting to read about using a trolling motor on a sailboat. My merit 22 came with an 8hp Honda that seemed to weigh 100 pounds. I took it off right away. It seemed like too much weight on my transom. I have an old Sears trolling motor so I thought that might work.

I guess there are good trolling motors and bad trolling motors. Mine didn't have enough thrust to move me out of my slip against a 5kt. breeze.

I eventually bought a 4hp Mercury long shaft and now have no trouble getting in and out.
 
Oct 29, 2012
289
Catalina 30 TRBS MkII Milwaukee
Thank you everyone for the information. This might be crazy but I'm thinking of having 2 outboards. Most of the time I wouldn't use both but having 2 makes me feel more secure. I want to go about 7 miles offshore to some islands eventually, so reliability and speed are important to me. My boat has a swing keel, so when lifted, and with mast and boom down, in an emergency, how much hp would be safe and how fast could I go? How much is hull speed affected by having the keel up?
All this is interesting coming from the perspective of owning both a 22 and 25 both of which were sailed from and back to the dock. Once in a great while only needing the small 2hp (7 hp long-shaft) to get that last 500 yards back to the dock when the wind died late in the evening.
The long shaft worked well in heavy seas to get across the harbor with the wind blowing stink on the nose.
Or when out night sailing, in light air and needing to maintain the battery with nav lights on and music playing, because of the alternator.
Don't forget the impact of having potentially over a hundred pounds of weight, in both engine and fuel hanging on one side of the vessel because OB motor mounts are generally on one side or the other. As well as the noise and exhaust smell in the cabin and cockpit.
If the concern is returning 7 miles from an off-shore island, as suggested, get a good set of sails. A main with two reefs points as well as a nice storm jib, or furling head-sail. My$0.02
 
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May 24, 2004
6,792
CC 30 South Florida
I had major concern should the up haul line ever break, I know major damage would occur which is why I left it down. The only time bringing it up if I ran aground or for launching/retrieving from the trailer. I learned a lot from that boat. Later I became a Sailboat dealer with emphasis on small boats.
That is good advice for a new owner. The swing keel should be locked in position with a pin or a bolt unless you are skimming in very shallow water or where obstructions can be anticipated. If the keel is left unlocked and the boat is knocked down by wind or waves that keel will retract like a "jack knife" with enough force to destroy the the keel trunk in the hull. By the same token locking the keel in shallow water while moving fast should the boat ground itself it may damage the keel support. My personal policy is to keep the keel locked and slow down the boat when approaching shallow water.
 
Jun 2, 2004
3,160
Hunter 23.5 Fort Walton Yacht Club, Florida
Two Considerations:

First, 3hp would probably be adequate and most motors of about that size do not have a reverse and many do not have a neutral gear. I'd want both.

Second above 6hp many of the motors have two versus one cylinders. If you are going to be motoring significant distances the two cylinder motor is much smoother and quieter than the single cylinder. The two cylinder motor is also heavier and uses a bit more fuel.

Just thought of a third consideration smaller motors tend to use a small internal fuel tank. That small tank would be enough for several hours use a three gallon external tank would last the whole weekend. Some motors can use either an internal or external tank. I'd not want to be adding gas to a hot motor at night in a lumpy sea.

For what you are describing I would look for the smallest motor with reverse and neutral and an external fuel tank.
 
Jan 19, 2010
10,002
Hunter 26 Charleston
That is good advice for a new owner. The swing keel should be locked in position with a pin or a bolt unless you are skimming in very shallow water or where obstructions can be anticipated. If the keel is left unlocked and the boat is knocked down by wind or waves that keel will retract like a "jack knife" with enough force to destroy the the keel trunk in the hull. By the same token locking the keel in shallow water while moving fast should the boat ground itself it may damage the keel support. My personal policy is to keep the keel locked and slow down the boat when approaching shallow water.
That is definitly true for the heavy cast iron type swing keels where the keel is the ballast... but for the water ballast boats, the "keel's" only function is to prevent lateral drift. There is no real ballast in the keel so it won't come busting through the trunk... and as such, there is no lock down pin. The advantage of this is that if you do "kiss" the bottom, the keel just rides up over the sandbar.... you don't tear your keel trunk up by striking with force.