I recently acquired a preowned '99 H 310 from a dealer who'd taken it in on trade. The boat sat unused for at least a few months, mabye an entire season before I got ahold of it. Other than learning the quirks, it seems to be working out extremely well, and I'm very happy with my new friend. My concern is that I have seen postings in this forum that indicate that either my knotmeter is fouled or not calibrated correctly, or my boat is moving through the water a lot slower than it should. I'm getting about 4.5kts under power at 3000 RPM in fresh water. I've never exceeded 5 kts under sail, in roughly 15kt winds. The hull speed rating, according to the specs, is 7kts. Someone has posted that they regularly exceed that number, which I find worrisome, given my experience. First question: are Hunters (or all sailboats) faster on salt water than fresh water? Second question: what should my expectations be, regarding hull speed under power vs. hull speed under sail? I haven't yet verified with a GPS. I guess that's the next thing to do. If that reveals that the knotmeter paddle-wheel is fouled, then the obvious solution is to clean or replace it. However, if it reveals that the meter is correct, then I am wondering what's going on. I have the original Raytheon (Autohelm?) instruments, but no manuals. I tried to figure out how to calibrate the knotmeter, but the method escapes me. I have the original 2-blade prop (Don't know about the size; I'll have to go under to measure it to find out). The Yanmar seems to be running well. I don't have anything to compare my experience with, however. Third question: would it be worth my while to replace the prop with a 3-blade? What would that accomplish, with regard to speed, acceleration, responsiveness, etc? Any and all feedback is much appreciated. Larry Baker c/v "Flat Broke" Grapevine, TX
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Dear Flatbroke
Borrow a GPS and see what it indicates vs. your knot/log. As I have recently learned, there will be a difference but not as dramatic as your exisitng 4.5 hull speed. The "normal" difference is because the knot log is affected by the rate of the "river flow" as opposed to the across land rate on the GPS. It shouldn't be that much though. I assume you have a clean bottom. Next time out on the hard you should check condition of cutlass bearing- there shouldnt be any play there. It does get subject to galvanic action. Jim McCue
Borrow a GPS and see what it indicates vs. your knot/log. As I have recently learned, there will be a difference but not as dramatic as your exisitng 4.5 hull speed. The "normal" difference is because the knot log is affected by the rate of the "river flow" as opposed to the across land rate on the GPS. It shouldn't be that much though. I assume you have a clean bottom. Next time out on the hard you should check condition of cutlass bearing- there shouldnt be any play there. It does get subject to galvanic action. Jim McCue
Cutlass play
The survey I got on the boat identified some play in the cutlass bearing, enough to suggest that it could be replaced in advance of its wearing to the point where it really needed to be replaced. Unfortunately, due to a series of logistical problems and missteps on my part, I didn't get it replaced while I had it out of the water. Can yuou advise on how to tell when it needs replacement? Am I correct in understanding that wear on the cutlass bearing can reduce effective power? Thx, Larry
The survey I got on the boat identified some play in the cutlass bearing, enough to suggest that it could be replaced in advance of its wearing to the point where it really needed to be replaced. Unfortunately, due to a series of logistical problems and missteps on my part, I didn't get it replaced while I had it out of the water. Can yuou advise on how to tell when it needs replacement? Am I correct in understanding that wear on the cutlass bearing can reduce effective power? Thx, Larry
Doubt that there may be a loss of power!
Larry: I doubt the fact that there would be any noticable difference in power with a worn cutlass bearing. These basically keep the shaft and the strut in line. When they wear you sometimes get some knocking when they are really worn. If can also cause scoring on the shaft and then you sometimes need to replace the shaft too (now we are talking about $100/ft or so). What I would do is get (borrow or steal) a GPS and run your boat over a measured distance both ways a couple of times and get some measurements between the GPS and the Knot meter. I would not do anything about a prop until you decide what is going on with your speed. A three bladed prop is not going to do anything about your speed in flat calm water under power. Unless you go to a folder or feathering prop it IS going to slow you down under sail. You also need to make sure that you have the correct prop for your engine/trans combo.
Larry: I doubt the fact that there would be any noticable difference in power with a worn cutlass bearing. These basically keep the shaft and the strut in line. When they wear you sometimes get some knocking when they are really worn. If can also cause scoring on the shaft and then you sometimes need to replace the shaft too (now we are talking about $100/ft or so). What I would do is get (borrow or steal) a GPS and run your boat over a measured distance both ways a couple of times and get some measurements between the GPS and the Knot meter. I would not do anything about a prop until you decide what is going on with your speed. A three bladed prop is not going to do anything about your speed in flat calm water under power. Unless you go to a folder or feathering prop it IS going to slow you down under sail. You also need to make sure that you have the correct prop for your engine/trans combo.
GPSing
I'm going to get a GPS this weekend. I should have data to share after that. I am very suspicious of the knotmeter. The previous owner of the boat had it a very short period before they traded it in (on a 320, go figure
. They bought it new, and I think there's a very good chance that the meter was never calibrated in the first place. I know the dealer that originally sold the boat first (they're the same one that sold it to me), so I'll check with them to see if they normally calibrate the instruments or not. My guess is not (knot?). Without a fairly accurate set of landmarks and a very steady hand at the helm, it would be difficult to do the calibration the way the manual specifies. Basically you reset the trip counter, then sail a known distance - long far enough to reduce statistical error (i.e. more than 2km), and use the knotmeter's idea of true distance and the chart distance to calculate a correction coefficient that you set on the instrument. Has anyone here calibrated their knotmeters? What sort of techinque did you use? What sort of variance did you discover that needed correction? Cheers, Larry
I'm going to get a GPS this weekend. I should have data to share after that. I am very suspicious of the knotmeter. The previous owner of the boat had it a very short period before they traded it in (on a 320, go figure
. They bought it new, and I think there's a very good chance that the meter was never calibrated in the first place. I know the dealer that originally sold the boat first (they're the same one that sold it to me), so I'll check with them to see if they normally calibrate the instruments or not. My guess is not (knot?). Without a fairly accurate set of landmarks and a very steady hand at the helm, it would be difficult to do the calibration the way the manual specifies. Basically you reset the trip counter, then sail a known distance - long far enough to reduce statistical error (i.e. more than 2km), and use the knotmeter's idea of true distance and the chart distance to calculate a correction coefficient that you set on the instrument. Has anyone here calibrated their knotmeters? What sort of techinque did you use? What sort of variance did you discover that needed correction? Cheers, LarryFollow-on
My comment about the cutless bearing was purely precautionary since this boat is 2nd hand. Its unrelated to your speed concern. JM
My comment about the cutless bearing was purely precautionary since this boat is 2nd hand. Its unrelated to your speed concern. JM
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