I find that the engine in this boat will not aproach hull speed as installed with a two blade prop - it is a Yanmar 18 horse. Allowing for the fact that the speed instrument is not calibrated accurately as I usally am in current so I have only gotten it approximate - however, I know it reads up to 6 knots under sail in heavy weather so I feel that is the top end of this boat (by that instrument) and will only approach 5 under power and that wouold be at 34 - 3600 RPM, not desirable, at 2800 or so it is about 4.5 knots. Is this experience the same for other owners? Would a three blade prop cure this? Thanks Ed
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Under Propped.
Ed: You should run you boat on a course of 2-3 miles with the current and against the current. Measure your speed with a GPS and the knot meter. It sounds like you may be a little under propped. Just remember as a rule of thumb that 1 deg of pitch +/- will change your rpms by about 250rpms. I would get the prop checked and sized for your boat and see what happens. Generally you are not going to see much if any difference in speed with a 3 blade vs 2 blade unless you are in heavy seas. In your case you may see some difference depending on the strength of the current. I am guessing that your engine would rev even higher if it were not for the govenor. Do you know what prop you have (ie: 15 x 12?)
Ed: You should run you boat on a course of 2-3 miles with the current and against the current. Measure your speed with a GPS and the knot meter. It sounds like you may be a little under propped. Just remember as a rule of thumb that 1 deg of pitch +/- will change your rpms by about 250rpms. I would get the prop checked and sized for your boat and see what happens. Generally you are not going to see much if any difference in speed with a 3 blade vs 2 blade unless you are in heavy seas. In your case you may see some difference depending on the strength of the current. I am guessing that your engine would rev even higher if it were not for the govenor. Do you know what prop you have (ie: 15 x 12?)
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nick
6.5
I have a 290 with the 18 hp yanmar the same as your engine. my max has been 6.5 hull speed under power with not much current, I have heard some guys complaining of the 326 being under power and the three blade prop not much help , check the archives .
I have a 290 with the 18 hp yanmar the same as your engine. my max has been 6.5 hull speed under power with not much current, I have heard some guys complaining of the 326 being under power and the three blade prop not much help , check the archives .
T
Tom Pfleeger
calibrate
Try calibrating your knotmeter with a GPS when you know there is little current. My 310 does 6.5 knots plus at 3400 rpm. I'm assuming you've checked the impeller, prop and you're not dragging a crab trap around!
Try calibrating your knotmeter with a GPS when you know there is little current. My 310 does 6.5 knots plus at 3400 rpm. I'm assuming you've checked the impeller, prop and you're not dragging a crab trap around!
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Scott Narum
My Experience
Ed, I've had my 326 for about 6 months and have 90 engine hours, so I've tested it plenty. I have the standard two blade prop. The hull speed for this boat is 7 knots. I have achieved this once when sailing in a stiff breeze on a reach with a spinnaker. Under motor, I get about 5.5 knots at 3000 rpm and about 6 knots at 3400 rpm. Of course, it does depend a lot on whether the wind is on the nose or stern. In any case, the 18 hp Yanmar is incapable of driving the boat hull speed, which I find to be disappointing. It is my opinion that Hunter should have put the 3 cylinder 27 hp Yanmar in this boat, but then it would require more space and the boat wouldn't get the amazing fuel economy it provides. Overall, I do like the engine, but more power would be nice. A three blade prop might get the boat to hull speed, too.
Ed, I've had my 326 for about 6 months and have 90 engine hours, so I've tested it plenty. I have the standard two blade prop. The hull speed for this boat is 7 knots. I have achieved this once when sailing in a stiff breeze on a reach with a spinnaker. Under motor, I get about 5.5 knots at 3000 rpm and about 6 knots at 3400 rpm. Of course, it does depend a lot on whether the wind is on the nose or stern. In any case, the 18 hp Yanmar is incapable of driving the boat hull speed, which I find to be disappointing. It is my opinion that Hunter should have put the 3 cylinder 27 hp Yanmar in this boat, but then it would require more space and the boat wouldn't get the amazing fuel economy it provides. Overall, I do like the engine, but more power would be nice. A three blade prop might get the boat to hull speed, too.
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Guest
Not Too Much Detail to Work On But .............
........ it sounds as if your prop just can't put out ie. under pitched or the diameter is too small. We will be getting our new prop increase 1" in pitch the next haulout as it won't quite put out enough. One acid test you might consider is accelerating your engine in gear while the boat is stopped in the water. If you can get the RPM to 3600 instantly while the boat is still motionless, the prop is undersized. Regards, Island Hunter
........ it sounds as if your prop just can't put out ie. under pitched or the diameter is too small. We will be getting our new prop increase 1" in pitch the next haulout as it won't quite put out enough. One acid test you might consider is accelerating your engine in gear while the boat is stopped in the water. If you can get the RPM to 3600 instantly while the boat is still motionless, the prop is undersized. Regards, Island Hunter
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Steve
Something else???
If you are turely loosing that much speed under engine power, then something is wrong. My 320 looses a little under a knot from engine power to wind power. Assuming you have the standard 2-bladed prop, it should drive the boat like mine and only loose a little. Your prop should be a 15X12 standard. You might check the bottom and make sure that you don't have something fouled on the bottom, or growth on the prop itself. Do you have excessive vibration? If so, does it increase with speed? Again, look for other problems that size of the engine or prop. BTH, a three bladed prop would typically decrease vibration, but drive the boat about the same. I put a folding 2-bladed Gori prop on mine this year, and it make a BIG difference on sailing speed (which is where I want the speed, since I bought a SAILboat). It drives the same speed as before, but I put up with slight more vibration and a slight decrease in to RPM due to the load. Steve
If you are turely loosing that much speed under engine power, then something is wrong. My 320 looses a little under a knot from engine power to wind power. Assuming you have the standard 2-bladed prop, it should drive the boat like mine and only loose a little. Your prop should be a 15X12 standard. You might check the bottom and make sure that you don't have something fouled on the bottom, or growth on the prop itself. Do you have excessive vibration? If so, does it increase with speed? Again, look for other problems that size of the engine or prop. BTH, a three bladed prop would typically decrease vibration, but drive the boat about the same. I put a folding 2-bladed Gori prop on mine this year, and it make a BIG difference on sailing speed (which is where I want the speed, since I bought a SAILboat). It drives the same speed as before, but I put up with slight more vibration and a slight decrease in to RPM due to the load. Steve
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Mike Webster
Under Propped
I agree with most of the responses to this post that you are probably under propped. I have a Vision 32, weight of 11,400, and 24 hp Yanmar diesel. My boat will do 5.8-6 knots at 2000 rpm, and 7+ knots at 2800 rpm. This has been confirmed by both calibrating my knotmeter over a measured course, and by using my GPS. This gives me plenty of reserve power for when the waves and wind pipe up. I've needed that reserve power a few times. Once, when I could only keep 3 knots of headway during a bad storm on the Chesapeake, and many times trying to break out of pier heads into open water during periods of high waves on Lake Michigan. Both of these are extreme challanges, but are encountered once in awhile. I had to change props in 95' when my old prop was attacked by galvanic corrosion and badly damaged. I ordered a new 17x10 prop from Michigan Wheel. It had a lot less thrust than the older 17x10 prop that came with the boat(I could barely make hull speed under full power/no wind/no wave conditions), and I questioned whether they sent the correct prop. I was assured they did. The next time I pulled the boat, I checked the new prop against the old prop, which I now use for a door stop. It was the correct diameter and pitch, but the old prop had a much wider blade, which accounted for its greater thrust. I had the new prop re-pitched to a 17-12, and I have my old performance back. I wanted to point this out to show that there can be additional factors that can also affect proper operation and speed under power. Also, don't assume its correct just because it came from the factory that way. I did some calculations on HP vs weight for recent Hunter 29's thru 33' models. All of the models thru 32', except the Vision 32, used the 2GM20 engine with 16hp rated, 18hp max output. Starting with the Vision 32, and the recent 33 footers, all used the 3GM30 engine with 24hp rated, 27hp max output. The following are the calculations: Hunter 29 -7400# - 463#/HP Hunter 29.5 - 7000# - 438#/HP Hunter 31 - 9900# - 550#/HP Hunter 310 - 8500# - 531#/HP Hunter 320 - 8550# - 534#/HP Hunter 326 - 8300# - 519#/HP Vision 32 - 11400# - 475#/HP Hunter 335 & 336 - 11000# - 458#/HP While many other items factor into boat speed, it does give a general comparison of how like boats should behave. Since, by throwing out the two extremes, all the other boats have #/HP ratios that are within about 15% of each other, and my Vision 32 reaches hull speed easily at 2800 rpm with a 20% reserve in rpm's, I would conclude that all of these boats have adequate power available. I would consider re-pitching your prop for better performance.
I agree with most of the responses to this post that you are probably under propped. I have a Vision 32, weight of 11,400, and 24 hp Yanmar diesel. My boat will do 5.8-6 knots at 2000 rpm, and 7+ knots at 2800 rpm. This has been confirmed by both calibrating my knotmeter over a measured course, and by using my GPS. This gives me plenty of reserve power for when the waves and wind pipe up. I've needed that reserve power a few times. Once, when I could only keep 3 knots of headway during a bad storm on the Chesapeake, and many times trying to break out of pier heads into open water during periods of high waves on Lake Michigan. Both of these are extreme challanges, but are encountered once in awhile. I had to change props in 95' when my old prop was attacked by galvanic corrosion and badly damaged. I ordered a new 17x10 prop from Michigan Wheel. It had a lot less thrust than the older 17x10 prop that came with the boat(I could barely make hull speed under full power/no wind/no wave conditions), and I questioned whether they sent the correct prop. I was assured they did. The next time I pulled the boat, I checked the new prop against the old prop, which I now use for a door stop. It was the correct diameter and pitch, but the old prop had a much wider blade, which accounted for its greater thrust. I had the new prop re-pitched to a 17-12, and I have my old performance back. I wanted to point this out to show that there can be additional factors that can also affect proper operation and speed under power. Also, don't assume its correct just because it came from the factory that way. I did some calculations on HP vs weight for recent Hunter 29's thru 33' models. All of the models thru 32', except the Vision 32, used the 2GM20 engine with 16hp rated, 18hp max output. Starting with the Vision 32, and the recent 33 footers, all used the 3GM30 engine with 24hp rated, 27hp max output. The following are the calculations: Hunter 29 -7400# - 463#/HP Hunter 29.5 - 7000# - 438#/HP Hunter 31 - 9900# - 550#/HP Hunter 310 - 8500# - 531#/HP Hunter 320 - 8550# - 534#/HP Hunter 326 - 8300# - 519#/HP Vision 32 - 11400# - 475#/HP Hunter 335 & 336 - 11000# - 458#/HP While many other items factor into boat speed, it does give a general comparison of how like boats should behave. Since, by throwing out the two extremes, all the other boats have #/HP ratios that are within about 15% of each other, and my Vision 32 reaches hull speed easily at 2800 rpm with a 20% reserve in rpm's, I would conclude that all of these boats have adequate power available. I would consider re-pitching your prop for better performance.
E
Ed
Thanks
Thanks for the info, I will try the dead stop test to see if the prop is under sized. As I said the knot meter is not perfectly calibrated but that goes out of the equation as it is the same device used to measure sail Vs. motor speed. If the bottom were fouled etc. I would also lose the speed under sail. Probably the prop. The boat is new and was launched for the first time July 1, so I know that the condition of the bottom and prop were pristine. However I would not be surprised to find it has the wrong prop or the prop is defective from a pitch angle. BTW how fast is it OK to run the engine for a two - three hour period? I have been under the impresion that 2800 would be correct, now I am wondering if somwhere above 3200 would be OK? Not looking for a speed boat under power, but the conditions I sail in here require passing through the race and entering some rivers with a 4-5 knot current against you, and it is a several mile moter from my dock to the sound - so a knot or two more of speed can be big!!! Again thanks for the input. Ed
Thanks for the info, I will try the dead stop test to see if the prop is under sized. As I said the knot meter is not perfectly calibrated but that goes out of the equation as it is the same device used to measure sail Vs. motor speed. If the bottom were fouled etc. I would also lose the speed under sail. Probably the prop. The boat is new and was launched for the first time July 1, so I know that the condition of the bottom and prop were pristine. However I would not be surprised to find it has the wrong prop or the prop is defective from a pitch angle. BTW how fast is it OK to run the engine for a two - three hour period? I have been under the impresion that 2800 would be correct, now I am wondering if somwhere above 3200 would be OK? Not looking for a speed boat under power, but the conditions I sail in here require passing through the race and entering some rivers with a 4-5 knot current against you, and it is a several mile moter from my dock to the sound - so a knot or two more of speed can be big!!! Again thanks for the input. Ed
2900 is ideal.
Ed: 2900 rpm is ideal. If you had enough fuel you could run it at this RPM until it is time to change the oil. I would suggest that you get your prop checked before you do any extended cruising.
Ed: 2900 rpm is ideal. If you had enough fuel you could run it at this RPM until it is time to change the oil. I would suggest that you get your prop checked before you do any extended cruising.
J
James Marohn
From another post...
Take a peek at the "related link" below. It's from the Yanmar site about operating RPMs. 2900 is good for the GM series... You forgot to mention your engine model...
Take a peek at the "related link" below. It's from the Yanmar site about operating RPMs. 2900 is good for the GM series... You forgot to mention your engine model...
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Ed Fluss
Just got my 326 and same issue!
I have been using my new 326 the last two weeks, the dealer is not really finished getting it commissioned, but I am seriously worried about the same issue. This weekend under full sail and 15+ knots of wind the boat was sailing at over 6 knots! GREAT! Under power I can only get the boat to barely 5.5 and that is at 3600-3800 RPM! I have had a H280 with the same engine. The 280 would do 5.2 at 2900 RPM and for years I had very few problems with the engine. This new engine on the H326 has a max RPM in forward of just over 3900 RPM. 80% of that would be about 3200 so I thinking that the boat should run at 3200 for cruising. While I am at it here. Are you having any difficulty with your SEAWATER STRAINER? It seems very small and is very hard to remove when eel grass clogs it. I plan a call to Hunter this week. This site is the best! Ed Fluss
I have been using my new 326 the last two weeks, the dealer is not really finished getting it commissioned, but I am seriously worried about the same issue. This weekend under full sail and 15+ knots of wind the boat was sailing at over 6 knots! GREAT! Under power I can only get the boat to barely 5.5 and that is at 3600-3800 RPM! I have had a H280 with the same engine. The 280 would do 5.2 at 2900 RPM and for years I had very few problems with the engine. This new engine on the H326 has a max RPM in forward of just over 3900 RPM. 80% of that would be about 3200 so I thinking that the boat should run at 3200 for cruising. While I am at it here. Are you having any difficulty with your SEAWATER STRAINER? It seems very small and is very hard to remove when eel grass clogs it. I plan a call to Hunter this week. This site is the best! Ed Fluss
Hold on, Ed of Fluss!
Ed: I/we have been assuming that you guys have 2GM20F engines. If that is the case, when we talk about MAX RATED RPM's we are speaking about the engine rating, NOT HOW HIGH it CAN REV. These engines are rated at 3600 rpm (max). They have a govenor that keeps the engine from reving too high. Now based on what you are describing I am sure you guys need at least more 2 deg of pitch and maybe 3 would not hurt. Once again, go to a prop shop and have them give you the numbers. Do no rely on your dealer or Hunter. Once you know what it should be, give the info to your dealer and let them proceed.
Ed: I/we have been assuming that you guys have 2GM20F engines. If that is the case, when we talk about MAX RATED RPM's we are speaking about the engine rating, NOT HOW HIGH it CAN REV. These engines are rated at 3600 rpm (max). They have a govenor that keeps the engine from reving too high. Now based on what you are describing I am sure you guys need at least more 2 deg of pitch and maybe 3 would not hurt. Once again, go to a prop shop and have them give you the numbers. Do no rely on your dealer or Hunter. Once you know what it should be, give the info to your dealer and let them proceed.
D
David
E
Ed Fluss
Dealer says
So I went over this with my dealer. He said I can run the engine at 3200-3500 rpm all day and it will be fine! Im going to test his words in a week on a day cruise from the South Shore of LongIsland to NY Harbor! Ed
So I went over this with my dealer. He said I can run the engine at 3200-3500 rpm all day and it will be fine! Im going to test his words in a week on a day cruise from the South Shore of LongIsland to NY Harbor! Ed
S
Steve W.
Last summer we chartered a Beneteau 331 in the
BVI's. It had a Westerbeke 30hp and would easily cruise at 6.5- 7.0 knots under power (GPS) at 2500 rpm. Two bladed prop. Same size boat, so I though I would offer this as a comparison. My Newport 28, 14hp Universal, two bladed prop, crusies at 5.5 knots (GPS) at 2350 rpm, 6 knots at 2600 rpm. 18 hp seems kind of underpowered for a 32' boat to me.
BVI's. It had a Westerbeke 30hp and would easily cruise at 6.5- 7.0 knots under power (GPS) at 2500 rpm. Two bladed prop. Same size boat, so I though I would offer this as a comparison. My Newport 28, 14hp Universal, two bladed prop, crusies at 5.5 knots (GPS) at 2350 rpm, 6 knots at 2600 rpm. 18 hp seems kind of underpowered for a 32' boat to me.
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