Yes the atomic 4 is rated at 30 HP but no one uses it near its HP peak level of RPM. So most people in sailboats use about 18-20 HP of the usable 30. Some of the older power boats may have revved that engine up to the HP peak level. I don't think I ever pushed mine over about 2200 rpm so that was around 18 HP to move my C&C 33. Great engines, last a LONG time. But they are all getting long in the tooth now.
On Mon, Aug 24, 2020 at 3:53 PM Rick Brass via CnC-List < cnc-list@cnc-list.com> wrote: > I believe the difference is between rated HP and shaft HP, which is > generally lower after things like transmission loss, accessory loads, and > friction. > > > > IIRC, an A4 was rated as 30HP, but the shaft HP was something like 17or > 18. Which is why an2 cylinder Yanmar is a suitable replacement foe an A4. > > > > Rick Brass > > Washington, NC > > > > > > *From:* CnC-List [mailto:cnc-list-boun...@cnc-list.com] *On Behalf Of *Joe > Della Barba via CnC-List > *Sent:* Monday, August 24, 2020 2:15 PM > *To:* cnc-list@cnc-list.com > *Cc:* Joe Della Barba <j...@dellabarba.com> > *Subject:* Re: Stus-List 37+ Cruise Speed > > > > What the heck is a 13hp Atomic 4? Mine is 30 HP. > > Joe > > Coquina > > On 8/24/2020 1:26 PM, Daniel A. Willis via CnC-List wrote: > > My 1973 30' Mk 1 had a 13hp atomic four but was re-engine 12 years ago > with a 20 hp Universal. She stops on a dime and handles very well with all > that power. I suspect some might simply have been re-powered over the years > as our Santiago was. > > > ------------------------------ > > > > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > >
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