mvweebles
Guru
- Joined
- Mar 21, 2019
- Messages
- 7,733
- Location
- United States
- Vessel Name
- Weebles
- Vessel Make
- 1970 Willard 36 Trawler
mvw
Yup, the bulbous bow concept and actual use can get confusing. A very smart friend had a bulbous bow added to his DeFever recently. He is ecstatic, not necessarily for any gains in fuel or flat water speed but for lesser pitching in big seas which allow him to then run faster. Commercial guys I've talked with say similar things on their 50 to 80 foot fishing vessels, big weather pluses.
Modeling and flat water sea trials may not tell the full tale. Lest I digress though, the 57 is as you note and others have found, a faster globe girdling Nordhavn than other Ns in the same size range.
I suspect prismatic coefficient has something to do with the speed of this boat. I don't remember about pitching - I know the N46 was pretty bad for pitching, especially the early ones before they moved the fuel tanks forward a tad. If you read Jim Leishman's re-write of VUP carefully, he basically says the bow on the N46 was too fine with too much reserve bouyancy and would benefit from a bit more waterline forward (recall, this was NA Jeff Lieshman's graduate thesis, so he wasn't an accomplished navel architect....yet). Having delivered several N46's north into prevailing weather, I can tell you that the boat rides much, much better without full tanks. After my first N46 delivery, I'd try to depart with about half-full tanks. More than enough to do the nearly 1000 nms to turn the corner at Juan de Fuca.
But I digress. Regardless, the N57 is a damn fine boat. I really like the 'chariot' flybridge which keeps the lines very low. The ability to reliably do 230+ nm days on-end is incredible - it really expands horizons and, in my opinion, increases safety as you can make some decent weather decisions. The Dashew FPB is quite a bit faster - gotta love that.
As Bill Lee, the great designer/builder of the Santa Cruz 50 sailboat said: "Fast is fun!" It's also safe.