Re: Stus-List The stern squats at high speed
Someone correct me if I'm wrong on this... The stern of a displacement hull vessel will begin to submerge as you approach hull speed. It's settling into the trough of its own wake(s). Even kayaks do it. Someone told me a long time ago that a displacement vessel could theoretically sink itself if it had enough power. YMMV Rob ___ This List is provided by the CC Photo Album. Please donate to the CC Photo Album to keep this list free for all subscribers. Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
Re: Stus-List The stern squats at high speed
Yes – it is simple physics. At 11-12 knots my stern is nearly under. A modern boat won’t sink, more like half-plane like those monster “motor yachts” from the 60s-70s with the huge V-12 Detroit Diesels that go up the river leaving a 6 foot wake. An old narrow clipper ship could potentially be sailed under. I have heard of it, not sure if it ever happened. Joe Della Barba Coquina CC 35 MK I From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Robert Gallagher via CnC-List Sent: Wednesday, January 14, 2015 3:11 PM To: cnc-list@cnc-list.com Subject: Re: Stus-List The stern squats at high speed Someone correct me if I'm wrong on this... The stern of a displacement hull vessel will begin to submerge as you approach hull speed. It's settling into the trough of its own wake(s). Even kayaks do it. Someone told me a long time ago that a displacement vessel could theoretically sink itself if it had enough power. YMMV Rob ___ This List is provided by the CC Photo Album. Please donate to the CC Photo Album to keep this list free for all subscribers. Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
Re: Stus-List The stern squats at high speed
Tom, My 36 does the same thing. It did with a fixed prop and it does it with a two blade Max Prop. I believe I also have an 18 prop but am not sure off the top of my head. If its fairly flat I can get 7 knots.It bothered me when I first got the boat but I'm rather used to it now and just accept it as normal squat. Mike Virginia Lee, 93295, 1978 CC 36 CB Sent from my iPad Mini On Jan 11, 2015, at 11:54, TOM VINCENT via CnC-List cnc-list@cnc-list.com wrote: I was wondering if anyone else has the same problem that I have with my 36' that has the 3 cylinder Yanmar 30 HP. While motoring if I increase the speed the stern starts squatting the faster I go. I top out at 6.5 knots of speed and the stern is way down. I have a martec 18'' folding prop and I do not know the pitch. Tom Vincent Frolic II 1979 36' CC ___ This List is provided by the CC Photo Album. Please donate to the CC Photo Album to keep this list free for all subscribers. Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com ___ This List is provided by the CC Photo Album. Please donate to the CC Photo Album to keep this list free for all subscribers. Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
Re: Stus-List The stern squats at high speed
Tom, That’s hull speed. Basically, your stern is in the trough of your bow wave. See the figures in the link below: http://www.boatdesign.net/forums/attachments/boat-design/5014d1137160350-displacement-hull-speed-calculation-rvaluepf.jpg http://www.boatdesign.net/forums/attachments/boat-design/5014d1137160350-displacement-hull-speed-calculation-rvaluepf.jpg - Paul E. 1981 CC 38 Landfall S/V Johanna Rose Carrabelle, FL On Jan 11, 2015, at 12:00 PM, cnc-list-requ...@cnc-list.com wrote: Date: Sun, 11 Jan 2015 11:54:00 -0500 From: TOM VINCENT tvince...@msn.com mailto:tvince...@msn.com To: CC Forum cnc-list@cnc-list.com mailto:cnc-list@cnc-list.com Subject: Stus-List The stern squats at high speed Message-ID: bay168-w12245ac078651d15ee5bd5eed...@phx.gbl mailto:bay168-w12245ac078651d15ee5bd5eed...@phx.gbl Content-Type: text/plain; charset=iso-8859-1 I was wondering if anyone else has the same problem that I have with my 36' that has the 3 cylinder Yanmar 30 HP. While motoring if I increase the speed the stern starts squatting the faster I go. I top out at 6.5 knots of speed and the stern is way down. I have a martec 18'' folding prop and I do not know the pitch. Tom Vincent Frolic II 1979 36' CC ___ This List is provided by the CC Photo Album. Please donate to the CC Photo Album to keep this list free for all subscribers. Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
Stus-List The stern squats at high speed
I was wondering if anyone else has the same problem that I have with my 36' that has the 3 cylinder Yanmar 30 HP. While motoring if I increase the speed the stern starts squatting the faster I go. I top out at 6.5 knots of speed and the stern is way down. I have a martec 18'' folding prop and I do not know the pitch. Tom Vincent Frolic II 1979 36' CC ___ This List is provided by the CC Photo Album. Please donate to the CC Photo Album to keep this list free for all subscribers. Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
Stus-List The stern squats at high speed
Hi Tom - I notice the same thing on my 30-1 - as I increase revs the stern squats. I have a two blade fixed prop on an Atomic 4. I sometimes adjust the throttle by looking over the stern rather than the speedo - kinda handy. At high revs my exhaust is completely underwater while it is a few inches above water at rest. I don't know if it is really a problem or just a matter of physics - my power boat does the same thing, albeit more drastically. Joe Boyle Zia, 1975 30-1 Annapolis Message: 5 Date: Sun, 11 Jan 2015 11:54:00 -0500 From: TOM VINCENT tvince...@msn.com To: CC Forum cnc-list@cnc-list.com Subject: Stus-List The stern squats at high speed Message-ID: bay168-w12245ac078651d15ee5bd5eed...@phx.gbl Content-Type: text/plain; charset=iso-8859-1 I was wondering if anyone else has the same problem that I have with my 36' that has the 3 cylinder Yanmar 30 HP. While motoring if I increase the speed the stern starts squatting the faster I go. I top out at 6.5 knots of speed and the stern is way down. I have a martec 18'' folding prop and I do not know the pitch. Tom Vincent Frolic II 1979 36' CC ___ This List is provided by the CC Photo Album. Please donate to the CC Photo Album to keep this list free for all subscribers. Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
Re: Stus-List The stern squats at high speed
Hi Tom - I 1981 30-1 675M81E, My boat has the Mertec 18 R 2 blade folding prop. It squats under 3/4 throttle as well. While it will not hurt a thing, you will get better traction and economy if you move some ballast forward The boat will have more waterline and moving more efficiently threw the water.Sometime it don't take much, With my boat I put a secondary water tank under the v-birth 12 gallon. Now I get her up to speed and back down to around 2200 rpm's and she catches hull speed.Well, When she has a clean dottom. Peace On Sun, Jan 11, 2015 at 12:13 PM, Joe at Zialater via CnC-List cnc-list@cnc-list.com wrote: Hi Tom - I notice the same thing on my 30-1 - as I increase revs the stern squats. I have a two blade fixed prop on an Atomic 4. I sometimes adjust the throttle by looking over the stern rather than the speedo - kinda handy. At high revs my exhaust is completely underwater while it is a few inches above water at rest. I don't know if it is really a problem or just a matter of physics - my power boat does the same thing, albeit more drastically. Joe Boyle Zia, 1975 30-1 Annapolis Message: 5 Date: Sun, 11 Jan 2015 11:54:00 -0500 From: TOM VINCENT tvince...@msn.com To: CC Forum cnc-list@cnc-list.com Subject: Stus-List The stern squats at high speed Message-ID: bay168-w12245ac078651d15ee5bd5eed...@phx.gbl Content-Type: text/plain; charset=iso-8859-1 I was wondering if anyone else has the same problem that I have with my 36' that has the 3 cylinder Yanmar 30 HP. While motoring if I increase the speed the stern starts squatting the faster I go. I top out at 6.5 knots of speed and the stern is way down. I have a martec 18'' folding prop and I do not know the pitch. Tom Vincent Frolic II 1979 36' CC ___ This List is provided by the CC Photo Album. Please donate to the CC Photo Album to keep this list free for all subscribers. Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com -- *Best regards,* *Curtis McDaniel, * *CC 30-MK1 East Coast Lady* Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover. -Mark Twain *cpt.b...@gmail.com bobhick...@rogers.com* * __/) * . ___ This List is provided by the CC Photo Album. Please donate to the CC Photo Album to keep this list free for all subscribers. Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
Re: Stus-List The stern squats at high speed
Join the club. We (and Curtis comments later) have a boat with a flat transom. Thus, we can notice the squat more than those with boats with extended sterns and reverse transoms. Mine (30-1) splatters diesel crud all over the bottom half of the transom as I am motoring at any speed at all. I used to put a hose on the exhaust, but that looked so bad that I decided I should just wash off the crud after a vigorous motor. Comments below on hull speed are relevant. I cruised on a friends motorsailor - at 7 knots (big motor) the boat was pretty level, at 8, the bow came up a foot and the stern dropped a foot, at 9, more of the same. Think about a power boat coming up on plane.. Physics rules. Gary - Original Message - From: Joe at Zialater via CnC-List cnc-list@cnc-list.com To: cnc-list@cnc-list.com Sent: Sunday, January 11, 2015 12:13 PM Subject: Stus-List The stern squats at high speed Hi Tom - I notice the same thing on my 30-1 - as I increase revs the stern squats. I have a two blade fixed prop on an Atomic 4. I sometimes adjust the throttle by looking over the stern rather than the speedo - kinda handy. At high revs my exhaust is completely underwater while it is a few inches above water at rest. I don't know if it is really a problem or just a matter of physics - my power boat does the same thing, albeit more drastically. Joe Boyle Zia, 1975 30-1 Annapolis Message: 5 Date: Sun, 11 Jan 2015 11:54:00 -0500 From: TOM VINCENT tvince...@msn.com To: CC Forum cnc-list@cnc-list.com Subject: Stus-List The stern squats at high speed Message-ID: bay168-w12245ac078651d15ee5bd5eed...@phx.gbl Content-Type: text/plain; charset=iso-8859-1 I was wondering if anyone else has the same problem that I have with my 36' that has the 3 cylinder Yanmar 30 HP. While motoring if I increase the speed the stern starts squatting the faster I go. I top out at 6.5 knots of speed and the stern is way down. I have a martec 18'' folding prop and I do not know the pitch. Tom Vincent Frolic II 1979 36' CC ___ This List is provided by the CC Photo Album. Please donate to the CC Photo Album to keep this list free for all subscribers. Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com ___ This List is provided by the CC Photo Album. Please donate to the CC Photo Album to keep this list free for all subscribers. Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
