Speed of the 37c

M

Morrie

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Jun 3, 2004
86
Hunter 37-cutter Hilo, Hawaii
Hi, My name is Morrie. I haven't been on this site for 3 to 4 years. I still own my 37c. It is moored in Honolulu. HI. I had to get a liver transplant a few years ago then came to Ohio to help aging parents. Lately, my main involvement with my baby, "Dreamer," is writing about my adventures sailing in the Hawaiian Islands. At this point I have no Idea when I'll be able to get back to Hawaii but I wonder if any of you 37c owners can answer a couple of questions for me? What speed is the fastest you have ever had your 37c going under sail? I would even appreciate estimates if no one knows for sure. And, does anyone know the hull speed for our boats?

I anyone is still participating in this forum that I know, greetings. I hope you have had good sailing since I last heard from you and had success at any repairs and modifications you have made.

Any help with my questions will be greatly appreciated.

Thanks in advance,
Morrie
 
justsomeguy

justsomeguy

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Feb 20, 2011
7,993
Island Packet 35 Tucson, AZ/San Carlos, MX
I can answer one of your questions.

Your theoretical hull speed is 1.34 times the square root of the length of your waterline, measured in feet.
 
M

Morrie

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Jun 3, 2004
86
Hunter 37-cutter Hilo, Hawaii
Thanks, justsomeguy. I'll have to get my calculator out There uded to be a place on this website that had the different models specs. Anyone know if it's still here? Or, anyone know the waterline measurement of the 37c?
 
M

Morrie

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Jun 3, 2004
86
Hunter 37-cutter Hilo, Hawaii
Oops. I found the specs page. Water line length is not listed, but hull speed is listed at 7.3. It seems like I remember going faster than that, but my memory's not so great these days.
 
justsomeguy

justsomeguy

.
Feb 20, 2011
7,993
Island Packet 35 Tucson, AZ/San Carlos, MX
Morrie said:
Oops. I found the specs page. Water line length is not listed, but hull speed is listed at 7.3. It seems like I remember going faster than that, but my memory's not so great these days.
Click to expand
You're very welcome!
Well, you now have the necessary tools to figure your waterline length. :D
 
M

Morrie

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Jun 3, 2004
86
Hunter 37-cutter Hilo, Hawaii
Oops again! lwl must mean length at water line and is listed at 30 feet. All I have to do is hang around here for a while and I can find answers to many questions.
 
Jackdaw

Jackdaw

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Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
Morrie said:
Oops again! lwl must mean length at water line and is listed at 30 feet. All I have to do is hang around here for a while and I can find answers to many questions.
Click to expand
LWL stands for Load Waterline Length. It is the waterline length when the boat is loaded to a defined displacement. It typically changes a few inches between totally empty and fully loaded as the boat lowers in the water.
 
Jim Legere

Jim Legere

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Jun 8, 2004
1,004
C&C Frigate 36 St. Margarets Bay, Nova Scotia
Morrie,

Tales of boat speed can be a little like fishing stories. However, anyone who has been out in big seas and big winds will tell you that our boats can go faster than our calculated hull speed. I will say this: I have never seen my knot log go above 10 knots, but I have seen it over 9 knots quite a few times, reaching along in 30+ kt. wind. (its an old Datamarine paddlewheel-type knot log that usually tracks the GPS SOG) :eek:
 
M

Morrie

.
Jun 3, 2004
86
Hunter 37-cutter Hilo, Hawaii
That's what I thought, I seems like I have seen mine up over 8 knots. Thanks again.
 
chuckwayne

chuckwayne

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Mar 20, 2004
1,729
Hunter 356 and 216 Portland, ME
keep in mind that that 1.34 factor is an empirical number based on studies of a lot of "old" - including sailing cargo ships - sailboats. Modern hulls often exceed that calculated number
 
A

Angus Fleming

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Dec 5, 2011
30
Hunter 37c Scotland
Speed fiend

When I let my mother helm last summer she managed to get 8.7kts on the log display but I am embarrassed to say I have yet to acheive this myself
 
Ed Schenck

Ed Schenck

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Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
Been a long time Morrie. Hope you get to see the boat soon. And at least 6 knots. :)
 
B

Blaise

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Jan 22, 2008
359
Hunter 37-cutter Bradenton
One more thing to consider. As the boat heels, the waterline length increases. As the LWL increases, so does the MTHS. The basis of the maximun theoretical hull speed equation is that when a displacement hull moves through the water, it creates a bow wave. Wave lengths are measured crest to crest or trough to trough. The number is the same. The faster the hull moves, the longer the wave that is formed. When the length of the wave equals the length of the boat on the water (LWL), the boat is at MTHS. To increase past this, the boat has to climb over the wave of her own making. Powerboaters refer to this as coming up on a plane.

The fastest we have ever seen Midnight Sun was 14.7 kts. We were wing and wing in 45kts of breeze during Tampa Bay Race Week in 1996. That was just while surfing down 8 ft waves.
 
Jackdaw

Jackdaw

.
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
chuckwayne said:
keep in mind that that 1.34 factor is an empirical number based on studies of a lot of "old" - including sailing cargo ships - sailboats. Modern hulls often exceed that calculated number
Click to expand
Its not quite empirical as you might think. The 1.34 is the froude number that when plugged into that calculation, gives a bow wave period that exactly equals the boats water line length. That's straight math and well understood.

This matters because when a boat gets 'trapped' inside its trough between the two waves, it can go no faster without external influence. What is less understood is what that influence is and how displacement boats can sometimes go faster. It partially depends on displacement; the lighter the more likely they are to slightly exceed it.

But in the end its all just a numbers game. Robert Perry calls the Hull Speed Number 'the most worthless number in yacht design.'
 
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