Re: Stus-List intermitent vibration/shudder in ocean swells
Your cutlass bearing may be on its way out. As the bearing wears, the clearances open up and allow the shaft to wobble. You can dive under the boat and check for play in the blades of the prop and play in the cutlass bearing. I have also had zincs come loose and "ride" the shaft. Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD On Jun 16, 2016 12:26 PM, "Andrew Means via CnC-List" wrote: > Hey all - > > My friends and I are currently in Tofino, BC on day 6 of a much needed > vacation. So far our Yanmar GM30F and 3-bladed max-prop have been > performing brilliantly, sipping diesel and pushing the boat through the > less-windy sections of Strait of Juan De Fuca and up and over some large > ocean swells on our way up to Tofino. > > Yesterday on the way up from Ucluelet I felt a shudder/vibration as the > boat crested a swell. It was short but pronounced. The motor didn’t change > RPM at all or seem under load. About 10 minutes later it happened again, > also over a swell. This time we had to lower the RPM of the engine and let > it idle - when we brought it back up it was smooth again. This happened > maybe 6 times over the course of the passage, always starting as we were at > the top of a swell. > > We’d been going through swells at the same angle under power the day > before with no trouble, the only difference this time was that the little > wind there was was behind us. > > The only thing I can think of is that one of the blades of the max prop is > feathering as we go over these swells. I have no idea how one would fix > that - or if there’s any way to do so without hauling the boat out (hoping > to avoid that mid-trip…) > > Any ideas? > > -- > Andrew Means > S.V. Safari - 1977 C&C 34 Mk I > Seattle, WA > > ___ > > This list is supported by the generous donations of our members. If you > like what we do, please help us pay for our costs by donating. All > Contributions are greatly appreciated! > > ___ This list is supported by the generous donations of our members. If you like what we do, please help us pay for our costs by donating. All Contributions are greatly appreciated!
Re: Stus-List intermitent vibration/shudder in ocean swells
The Max-Prop may be worn and need to be rebuilt. Check for looseness in the blades when it is hauled. I had something similar happen when motor sailing when my prop was worn. When the wind would puff and accelerate the boat taking the load off the prop, it would shudder. Eric C&C 34/36 On Thu, Jun 16, 2016 at 2:59 PM, Tom Buscaglia via CnC-List < cnc-list@cnc-list.com> wrote: > Check your motor mounts. > > Tom Buscaglia > S/V Alera > 1990 C&C 37+/40 > Vashon WA > P 206.463.9200 > > > > On Jun 16, 2016, at 10:36 AM, cnc-list-requ...@cnc-list.com wrote: > > > > Message: 1 > > Date: Thu, 16 Jun 2016 09:25:00 -0700 > > From: Andrew Means > > To: cnc-list@cnc-list.com > > Subject: Stus-List intermitent vibration/shudder in ocean swells > > Message-ID: > > > > Content-Type: text/plain; charset="utf-8" > > > > Hey all - > > > > My friends and I are currently in Tofino, BC on day 6 of a much needed > > vacation. So far our Yanmar GM30F and 3-bladed max-prop have been > > performing brilliantly, sipping diesel and pushing the boat through the > > less-windy sections of Strait of Juan De Fuca and up and over some large > > ocean swells on our way up to Tofino. > > > > Yesterday on the way up from Ucluelet I felt a shudder/vibration as the > > boat crested a swell. It was short but pronounced. The motor didn?t > change > > RPM at all or seem under load. About 10 minutes later it happened again, > > also over a swell. This time we had to lower the RPM of the engine and > let > > it idle - when we brought it back up it was smooth again. This happened > > maybe 6 times over the course of the passage, always starting as we were > at > > the top of a swell. > > > > We?d been going through swells at the same angle under power the day > before > > with no trouble, the only difference this time was that the little wind > > there was was behind us. > > > > The only thing I can think of is that one of the blades of the max prop > is > > feathering as we go over these swells. I have no idea how one would fix > > that - or if there?s any way to do so without hauling the boat out > (hoping > > to avoid that mid-trip?) > > > > Any ideas? > > > > -- > > Andrew Means > > S.V. Safari - 1977 C&C 34 Mk I > > Seattle, WA > > ___ > > This list is supported by the generous donations of our members. If you > like what we do, please help us pay for our costs by donating. All > Contributions are greatly appreciated! > ___ This list is supported by the generous donations of our members. If you like what we do, please help us pay for our costs by donating. All Contributions are greatly appreciated!
Stus-List intermitent vibration/shudder in ocean swells
Check your motor mounts. Tom Buscaglia S/V Alera 1990 C&C 37+/40 Vashon WA P 206.463.9200 > On Jun 16, 2016, at 10:36 AM, cnc-list-requ...@cnc-list.com wrote: > > Message: 1 > Date: Thu, 16 Jun 2016 09:25:00 -0700 > From: Andrew Means > To: cnc-list@cnc-list.com > Subject: Stus-List intermitent vibration/shudder in ocean swells > Message-ID: > > Content-Type: text/plain; charset="utf-8" > > Hey all - > > My friends and I are currently in Tofino, BC on day 6 of a much needed > vacation. So far our Yanmar GM30F and 3-bladed max-prop have been > performing brilliantly, sipping diesel and pushing the boat through the > less-windy sections of Strait of Juan De Fuca and up and over some large > ocean swells on our way up to Tofino. > > Yesterday on the way up from Ucluelet I felt a shudder/vibration as the > boat crested a swell. It was short but pronounced. The motor didn?t change > RPM at all or seem under load. About 10 minutes later it happened again, > also over a swell. This time we had to lower the RPM of the engine and let > it idle - when we brought it back up it was smooth again. This happened > maybe 6 times over the course of the passage, always starting as we were at > the top of a swell. > > We?d been going through swells at the same angle under power the day before > with no trouble, the only difference this time was that the little wind > there was was behind us. > > The only thing I can think of is that one of the blades of the max prop is > feathering as we go over these swells. I have no idea how one would fix > that - or if there?s any way to do so without hauling the boat out (hoping > to avoid that mid-trip?) > > Any ideas? > > -- > Andrew Means > S.V. Safari - 1977 C&C 34 Mk I > Seattle, WA ___ This list is supported by the generous donations of our members. If you like what we do, please help us pay for our costs by donating. All Contributions are greatly appreciated!
Re: Stus-List intermitent vibration/shudder in ocean swells
One blade can't feather without the others feathering. Alan Bergen On Thu, Jun 16, 2016 at 9:25 AM, Andrew Means via CnC-List < cnc-list@cnc-list.com> wrote: > Hey all - > > My friends and I are currently in Tofino, BC on day 6 of a much needed > vacation. So far our Yanmar GM30F and 3-bladed max-prop have been > performing brilliantly, sipping diesel and pushing the boat through the > less-windy sections of Strait of Juan De Fuca and up and over some large > ocean swells on our way up to Tofino. > > Yesterday on the way up from Ucluelet I felt a shudder/vibration as the > boat crested a swell. It was short but pronounced. The motor didn’t change > RPM at all or seem under load. About 10 minutes later it happened again, > also over a swell. This time we had to lower the RPM of the engine and let > it idle - when we brought it back up it was smooth again. This happened > maybe 6 times over the course of the passage, always starting as we were at > the top of a swell. > > We’d been going through swells at the same angle under power the day > before with no trouble, the only difference this time was that the little > wind there was was behind us. > > The only thing I can think of is that one of the blades of the max prop is > feathering as we go over these swells. I have no idea how one would fix > that - or if there’s any way to do so without hauling the boat out (hoping > to avoid that mid-trip…) > > Any ideas? > > -- > Andrew Means > S.V. Safari - 1977 C&C 34 Mk I > Seattle, WA > > ___ > > This list is supported by the generous donations of our members. If you > like what we do, please help us pay for our costs by donating. All > Contributions are greatly appreciated! > > ___ This list is supported by the generous donations of our members. If you like what we do, please help us pay for our costs by donating. All Contributions are greatly appreciated!
Re: Stus-List intermitent vibration/shudder in ocean swells
A friend had the same issue, the problem was apparently that the water flow over the prop was neutral/reversing when the boat surfed momentarily. His solution, after much dollar spendage and mechanic guessing, was to motor at a speed that didn't produce the problem. Jim Watts Paradigm Shift C&C 35 Mk III Victoria, BC On 16 June 2016 at 09:50, S Thomas via CnC-List wrote: > I wonder if that little bit of wind was just enough to tilt the boat > forward so that the prop was sucking air momentarily as the bow tipped down > over the top. Could that cause the prop to feather? Power boat racers have > a person assigned to the throttle in swells. I don't have a feathering > prop, just speculating out loud. > > Steve Thomas > C&C27 MKIII > Port Stanley, ON > - Geared Gori prop > > - Original Message - > *From:* Andrew Means via CnC-List > *To:* cnc-list@cnc-list.com > *Cc:* Andrew Means > *Sent:* Thursday, June 16, 2016 12:25 > *Subject:* Stus-List intermitent vibration/shudder in ocean swells > > Hey all - > > My friends and I are currently in Tofino, BC on day 6 of a much needed > vacation. So far our Yanmar GM30F and 3-bladed max-prop have been > performing brilliantly, sipping diesel and pushing the boat through the > less-windy sections of Strait of Juan De Fuca and up and over some large > ocean swells on our way up to Tofino. > > Yesterday on the way up from Ucluelet I felt a shudder/vibration as the > boat crested a swell. It was short but pronounced. The motor didn’t change > RPM at all or seem under load. About 10 minutes later it happened again, > also over a swell. This time we had to lower the RPM of the engine and let > it idle - when we brought it back up it was smooth again. This happened > maybe 6 times over the course of the passage, always starting as we were at > the top of a swell. > > We’d been going through swells at the same angle under power the day > before with no trouble, the only difference this time was that the little > wind there was was behind us. > > The only thing I can think of is that one of the blades of the max prop is > feathering as we go over these swells. I have no idea how one would fix > that - or if there’s any way to do so without hauling the boat out (hoping > to avoid that mid-trip…) > > Any ideas? > > -- > Andrew Means > S.V. Safari - 1977 C&C 34 Mk I > Seattle, WA > > -- > > ___ > > This list is supported by the generous donations of our members. If you > like what we do, please help us pay for our costs by donating. All > Contributions are greatly appreciated! > > > ___ > > This list is supported by the generous donations of our members. If you > like what we do, please help us pay for our costs by donating. All > Contributions are greatly appreciated! > > ___ This list is supported by the generous donations of our members. If you like what we do, please help us pay for our costs by donating. All Contributions are greatly appreciated!
Re: Stus-List intermitent vibration/shudder in ocean swells
I wonder if that little bit of wind was just enough to tilt the boat forward so that the prop was sucking air momentarily as the bow tipped down over the top. Could that cause the prop to feather? Power boat racers have a person assigned to the throttle in swells. I don't have a feathering prop, just speculating out loud. Steve Thomas C&C27 MKIII Port Stanley, ON - Geared Gori prop - Original Message - From: Andrew Means via CnC-List To: cnc-list@cnc-list.com Cc: Andrew Means Sent: Thursday, June 16, 2016 12:25 Subject: Stus-List intermitent vibration/shudder in ocean swells Hey all - My friends and I are currently in Tofino, BC on day 6 of a much needed vacation. So far our Yanmar GM30F and 3-bladed max-prop have been performing brilliantly, sipping diesel and pushing the boat through the less-windy sections of Strait of Juan De Fuca and up and over some large ocean swells on our way up to Tofino. Yesterday on the way up from Ucluelet I felt a shudder/vibration as the boat crested a swell. It was short but pronounced. The motor didn’t change RPM at all or seem under load. About 10 minutes later it happened again, also over a swell. This time we had to lower the RPM of the engine and let it idle - when we brought it back up it was smooth again. This happened maybe 6 times over the course of the passage, always starting as we were at the top of a swell. We’d been going through swells at the same angle under power the day before with no trouble, the only difference this time was that the little wind there was was behind us. The only thing I can think of is that one of the blades of the max prop is feathering as we go over these swells. I have no idea how one would fix that - or if there’s any way to do so without hauling the boat out (hoping to avoid that mid-trip…) Any ideas? -- Andrew Means S.V. Safari - 1977 C&C 34 Mk I Seattle, WA -- ___ This list is supported by the generous donations of our members. If you like what we do, please help us pay for our costs by donating. All Contributions are greatly appreciated! ___ This list is supported by the generous donations of our members. If you like what we do, please help us pay for our costs by donating. All Contributions are greatly appreciated!
Stus-List intermitent vibration/shudder in ocean swells
Hey all - My friends and I are currently in Tofino, BC on day 6 of a much needed vacation. So far our Yanmar GM30F and 3-bladed max-prop have been performing brilliantly, sipping diesel and pushing the boat through the less-windy sections of Strait of Juan De Fuca and up and over some large ocean swells on our way up to Tofino. Yesterday on the way up from Ucluelet I felt a shudder/vibration as the boat crested a swell. It was short but pronounced. The motor didn’t change RPM at all or seem under load. About 10 minutes later it happened again, also over a swell. This time we had to lower the RPM of the engine and let it idle - when we brought it back up it was smooth again. This happened maybe 6 times over the course of the passage, always starting as we were at the top of a swell. We’d been going through swells at the same angle under power the day before with no trouble, the only difference this time was that the little wind there was was behind us. The only thing I can think of is that one of the blades of the max prop is feathering as we go over these swells. I have no idea how one would fix that - or if there’s any way to do so without hauling the boat out (hoping to avoid that mid-trip…) Any ideas? -- Andrew Means S.V. Safari - 1977 C&C 34 Mk I Seattle, WA ___ This list is supported by the generous donations of our members. If you like what we do, please help us pay for our costs by donating. All Contributions are greatly appreciated!
