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motoring speed
Posted: Fri Aug 06, 2010 11:59 am
by saltyrogue
I know this topic has been addressed before, but perhaps someone has new information/ experiences. Because motoring is such a drag- noisy, boring, no sails to analyze and tune- I just want to get it over with as quickly as possible, especially when heading back to harbor on a slack afternoon. Has anyone managed to get their 26s or d over hull speed without a massive input of horsepower. I realize that this may be something every new owner muses about before resigning him or herself to simply slogging out the miles. My musing and led me to question the amount of ballast needed to support a sail, and that perhaps not as much ballast is needed for motoring. This would change the wetted surface of the hull and maybe reduce the bow wave, etc. I read in one post, possibly from another forum, where a older couple planned to turn their 26d into a cabin cruiser, and planned to experiment with reducing ballast and hanging a larger engine off the transom. This would mean that some sort of baffle would need to be installed in the ballast tank to prevent a sloshing effect, or perhaps adding permanent ballast (rubber hose filled with lead shot?), and increasing that ballast for sailing by adding water. I have also read where people have weighted their centerboard with lead, I believe the record was 130-odd pounds, and noticed the boat felt more stable when heeling. I wonder if a weighted centerboard in the retracted position and some additional permanent ballast may be sufficient for motoring, especially if the mast is down and the water is glass.
If nothing else, it would be good to hear the max speeds people have achieved in their classics and under what conditions. (X and M owners- this is where you chuckle and get to enjoy that smug feeling).
Cheers,
Dave
Re: motoring speed
Posted: Fri Aug 06, 2010 12:23 pm
by ChockFullOnuts22
I'm not quite sure how to determine hull speed. Some people say that hull speed is as fast as your hull will allow you to move under power, or your hull's built-in limitation on speed. But that leaves room for someone to say that their boat goes faster than the next guy's, so how do you know if anyone exceeded hull speed or not? Maybe I'm missing something.
I don't have a 26 D or S, but my V2-22 does have a displacement hull like the 26's have (although far more flat on the bottom). With a 9.5 Evinrude/Johnson, I had no problem getting the boat to move fairly quick. Of course, the V2-22 is a keel boat, and raising the keel moves the center of gravity noticeably aft (keel weighs 500-550 Lbs). I doubt that the lightweight swing-up centerboard on the 26 would have as much as an effect, though. Anyway, with the keel in the up position, my bow rides higher out of the water and the hull planes a little better under outboard power. When I had to downgrade to a 6 hp outboard, I noticed a big change in the speed I could get. The power isn't enough to do what the other outboard did in my case. In fact, with this motor, there's not a huge difference between the speed with the keel down and with the keel up.
Re: motoring speed
Posted: Fri Aug 06, 2010 1:44 pm
by beene
saltyrogue wrote:perhaps not as much ballast is needed for motoring. This would change the wetted surface of the hull and maybe reduce the bow wave
Hi Dave
my .02
Just be sure you don't dump some of the water in your tank and just try that out. Anything less than full tank will allow the water to imbalance your boat, causing a potential capsize.
I feel your pain btw.
I had a Sandpiper for years b4 I bought my M. Time after time I would sail all day, wind would die completely, I would be 8 miles out or more, and the pain of max hull speed being around 4-5 kts was killing me. I had a 7.5 Honda and it would not push above hull speed. If I tried to push the boat, the motor would just loaf and strain unable to reach proper rpm.
I could not out run the bugs, the heat, you name it.
No fun.
That is one of the main reasons I traded up to the M. I wanted to be able to sail all day, and if the wind died, no big deal, drop the iron genny and zip home in time for dinner.
Cheers
G
Re: motoring speed
Posted: Fri Aug 06, 2010 2:08 pm
by DaveB
Dave, a friend of mine that has a Mac.S was following me in one day and staid right with me at doing 6.8 knots on his older 7.5 honda.
I usually cruise at 6 knots and only time I get to use the HP is when I want to empty Ballast.
I will at times do 9 -10 knots to avoid a Thunderstorm and at that speed burns way to much fuel, top end on my 50hp Honda is 13.5 knots with my heavy gear aboard and empty balast.
You won't get better than 7 knots on the Mac.S under power even if you went to a 9.9 hp engine as the hull displacement is not designed for planeing speeds.
If you put twin rudders on your boat and make a center transum bracket for a 60 hp outboard you will out perform the laws of pysics and power plane possibly doing 14 knots or more but would be very unstable in anything over a 2 ft. seas.
In the Bahamas they would say...Whach Ya Hurry Mon.
In Cape Cod they would say...Slow down to a Galup.
Dave
saltyrogue wrote:I know this topic has been addressed before, but perhaps someone has new information/ experiences. Because motoring is such a drag- noisy, boring, no sails to analyze and tune- I just want to get it over with as quickly as possible, especially when heading back to harbor on a slack afternoon. Has anyone managed to get their 26s or d over hull speed without a massive input of horsepower. I realize that this may be something every new owner muses about before resigning him or herself to simply slogging out the miles. My musing and led me to question the amount of ballast needed to support a sail, and that perhaps not as much ballast is needed for motoring. This would change the wetted surface of the hull and maybe reduce the bow wave, etc. I read in one post, possibly from another forum, where a older couple planned to turn their 26d into a cabin cruiser, and planned to experiment with reducing ballast and hanging a larger engine off the transom. This would mean that some sort of baffle would need to be installed in the ballast tank to prevent a sloshing effect, or perhaps adding permanent ballast (rubber hose filled with lead shot?), and increasing that ballast for sailing by adding water. I have also read where people have weighted their centerboard with lead, I believe the record was 130-odd pounds, and noticed the boat felt more stable when heeling. I wonder if a weighted centerboard in the retracted position and some additional permanent ballast may be sufficient for motoring, especially if the mast is down and the water is glass.
If nothing else, it would be good to hear the max speeds people have achieved in their classics and under what conditions. (X and M owners- this is where you chuckle and get to enjoy that smug feeling).
Cheers,
Dave
Re: motoring speed
Posted: Fri Aug 06, 2010 2:31 pm
by jim nolan
I always wondered what would happen if you put a 50 horse on a 21 , 22, 25 etc. and cranked it up. anybody know? jim nolan
Re: motoring speed
Posted: Fri Aug 06, 2010 4:36 pm
by Sumner
saltyrogue wrote:........ My musing and led me to question the amount of ballast needed to support a sail, and that perhaps not as much ballast is needed for motoring. This would change the wetted surface of the hull and maybe reduce the bow wave, etc. I read in one post, possibly from another forum, where a older couple planned to turn their 26d into a cabin cruiser, and planned to experiment with reducing ballast and hanging a larger engine off the transom.....
We left the ramp one day and the boat felt awful, not stable at all. We got about 1/8 to 1/4 mile out and I realized we hadn't put the ballast in our S. Filled the ballast and it was again stable. I wouldn't want to motor without the ballast or even be out on the lake without the ballast. The S and D has a very different bottom on it than the X or M and I feel, just a gut feeling, that the type of bottom shape we have needs ballast to be stable. Without it I would suggest that it feels and acts like a canoe when you stand up and move the center of gravity up.
I don't think you are going to have any luck going faster than about 7 mph,
Sum
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Re: motoring speed
Posted: Fri Aug 06, 2010 8:17 pm
by Captain Steve
There is a formula to calculate the hull speed for any given boat.
Re: motoring speed
Posted: Fri Aug 06, 2010 8:50 pm
by David Mellon
True, there is a formula for judging hull speed, the trick is to get going so fast your hull isn't in the water! I can maintain 19 mph, but if I toss the crew and their beer overboard I can get up to a solid 21 mph!