I just remembered another factor separting the bigger boat experience from yours. Do you have a 3 blade prop? The 3 blades make a big difference converting the engine power to boat speed.
Josh On Jan 12, 2015 10:45 AM, "Josh Muckley" <[email protected]> wrote: > When you are experiencing heavy currents and can only go 3 kts to round > the mark. Is that 3 kts being measured by the gps or is it 3 kts measured > by the speed log? It sounds to me like it is 3kts by gps and if so then > from all of the other listers comments and my own experience a larger > engine would only allow you to proceed at 4kts. > > When people experience a mismatch between boat size and drive train > performance it is most often experienced in heavy chop. I believe there > are two main factors at work in these "under powered" cases. > > The first is the diameter of the prop. Smaller engines = smaller props = > less bite in the water and when things get sloppy the prop slips and > cavitates more. > > The second part is prop speed. In order to use a smaller engine to do the > same job the designers will gear it to gain mechanical advantage. The prop > will have to spin faster than its higher powered counterparts. Faster > prop=less bite and closer to cavitation. > > When these two factors are at play the speed log will slow > disproportionately to the gps speed. Everyone has probably experienced > plunging the bow into a breaker and seeing the boat speed come down. The > question is how long does it take go recover. These smaller props spinning > at higher rpm slip and cavitate more so speed recovery is longer. If the > next breaker gets to you before the speed recovers.... > > Remind me, your boat, Lolita?, has an A4 right? Is it direct drive? If > my recollections are correct then you have a couple of things that set your > experiences apart from what you could expect from a larger diesel powered > boat such as a 37+, 38LF, or a 40. Forgive me if my recollections are > incorrect. > > First is that the gas engines don't have as much low end torque so when > those breakers come and the boat needs to make up, the engine has a harder > time coming back up to speed. > > Second, the direct drive (1:1) means that right from the start the prop > has to spin much faster and an increase in load at the prop is directly > felt as an increase in load at the engine. There are no gears to help in > having less low end torque so the prop pitch is much less as well, again > meaning more cavitation. > > Third, being a shorter and lighter boat means that the breakers will cause > the boat to hobby-horse around a lot more and also push the bow off > requiring more helm. > > All of these factors make for a less comfortable ride and slower progress > in the thick stuff. > > Good Luck, > > Josh Muckley > S/V Sea Hawk > 1989 C&C 37+ > Solomons, MD > On Jan 12, 2015 7:10 AM, "Danny Haughey via CnC-List" < > [email protected]> wrote: > >> I think my point is; >> >> Where we sail there are some pretty good currents and the chop picks up >> quite often. Sometimes, you have to make it home heading into both. >> That's when you want the extra hp. We sometimes have guests that get a >> little nervous when the conditions get exciting and we try to get them in >> as quickly as possible. Sure, you can move along at hull speed in >> favorable conditions but, the only time I'd be able to notice that the >> stern dug in a few inches would be in the harbour, sometimes. We almost >> never experience flat water and are typically dealing with a 3 to 4 knot >> current. Sometimes it is our favor and usually try to time our trips so it >> is. But day sailing, I don't really care as much. I sometimes could only >> get 3 knots under full power trying to round a mark to get into a harbour. >> That can be a little unnerving. >> >> Danny >> >> >> From my Android phone >> >> >> -------- Original message -------- >> From: Chuck S <[email protected]> >> Date: 01/11/2015 11:45 PM (GMT-05:00) >> To: Danny Haughey <[email protected]>,"CNC boat owners, cnc-list" < >> [email protected]> >> Subject: Re: Stus-List C&C 37+ engine size >> >> >> ". . . bigger is better. . . "? Is a bigger booty better? Will a bigger >> anchor make my sailboat go faster? >> What helps sailing is "no engine". Light means flight. >> Research the brochures and look to buy a boat with the "designed right >> size engine", not bigger. An upgrade would be a smaller diesel w a turbo. >> Just sayin. >> >> Chuck >> >> >> ------------------------------ >> *From: *"Danny Haughey via CnC-List" <[email protected]> >> *To: *[email protected] >> *Sent: *Sunday, January 11, 2015 7:54:45 AM >> *Subject: *Re: Stus-List C&C 37+ engine size >> >> Ok well, I guess it is adequate then. I just tend to see 40 hp engines >> in most 40 footers. >> >> Maybe not be the ideal and will be a bargaining point if it comes to that. >> >> Bigger is better in this instance I think... >> >> Thanks for the insights guys! >> >> Danny >> >> >> From my Android phone >> >> >> -------- Original message -------- >> From: allen via CnC-List <[email protected]> >> Date: 01/10/2015 3:53 PM (GMT-05:00) >> To: Robert Abbott <[email protected]>,[email protected] >> Subject: Re: Stus-List C&C 37+ engine size >> >> >> Our 30-2 has 20 hp Universal and easily reaches hull speed in light to >> calm conditions. Originally it was powered by an 18 hp Universal that >> netted 16. >> >> Allen Miles >> s/v Septima >> >> *From:* Robert Abbott via CnC-List <[email protected]> >> *Sent:* Saturday, January 10, 2015 3:41 PM >> *To:* Danny Haughey <[email protected]> ; [email protected] >> *Subject:* Re: Stus-List C&C 37+ engine size >> >> Danny: >> Some say if you have one hp per foot of boat, you are adequately powered >> for a sailboat. A 35 hp diesel in a 37+ seems adequate to me. >> >> Rob Abbott >> AZURA >> C&C 32 - 84 >> Halifax, N.S. >> >> >> On 2015/01/10 12:30 PM, Danny Haughey via CnC-List wrote: >> >> Hi Guys, >> >> I'm eyeing a 1989 37+ but it has a 35 HP universal diesel. That, seems >> kind of small for a nearly 40' boat. doesn't it? >> >> Danny >> >> >> >> ------------------------------ >> >> _______________________________________________ >> This List is provided by the C&C Photo Album. >> >> Please donate to the C&C Photo Album to keep this list free for all >> subscribers. >> >> Email address: >> [email protected] >> 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 C&C Photo Album. >> >> Please donate to the C&C Photo Album to keep this list free for all >> subscribers. >> >> Email address: >> [email protected] >> 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 C&C Photo Album. >> >> Please donate to the C&C Photo Album to keep this list free for all >> subscribers. >> >> Email address: >> [email protected] >> To change your list preferences, including unsubscribing -- go bottom of >> page at: >> http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com >> >> >>
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