[C38] Boat Speed

[Rich West]

The hull speed formula is 1.34 times the square root of the waterline
length.  In the case of our boats with a LWL of 30.25 feet, that comes out
to 7.37 knots.
 
The problem with speed reports is that you have no idea how accurate the
data is.  Is it from a GPS?  Was there a current with the boat when the
reading was taken?  Or is it someone looking at the peaks in speed on their
knot log?
 
On a trip to Hawaii, we left at the same time as  a Lapworth 40.  We had set
up a radio schedule to stay in contact through the trip.  He told us that
we'd have to go to a higher frequency as the trip progressed as he had a
much faster boat than ours and would get way ahead.  We were in no hurry and
figured he was right.  During the trip, we talked every day and reported our
position and boat speed.  While we were reporting an average speed over 24
hours in the 5 to 6 knot range, he'd consistently tell us he was doing 7 or
8 knots.  Position reports showed us gaining 20 or 30 miles a day the
Lapworth.  
 
I guess he didn't plot our position relative to his, or he didn't believe
our reports, but there was dead silence on the radio when we reported that
we were hook-down in Radio Bay, Hawaii and he still had well over two days
to go.  Yea, I'd say our boats are fast, even when you don't try.
 
Rich, Legacy, #360, San Diego
 

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From: listserve-bounces at catalina38.org
[mailto:listserve-bounces at catalina38.org] On Behalf Of Patrick Harpole
Sent: Thursday, July 09, 2009 8:49 AM
To: drstrong at ucdavis.edu; 'Catalina 38 Listserve'
Subject: Re: [C38] Boat Speed



What is the formula for hull speed?  Square root of length at water line
divided by something?

That's as fast as displacement boat will go

Patrick

Blue Eyes

S.F. Bay

 

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From: listserve-bounces at catalina38.org
[mailto:listserve-bounces at catalina38.org] On Behalf Of D. R. Strong
Sent: Thursday, July 09, 2009 8:37 AM
To: Catalina 38 Listserve
Subject: Re: [C38] Boat Speed

 

Paul:  
    Fast with sailboats is relative. The C38 is lots faster than the C34,
which means that in a mile and decent wind, the C38 can go about 50 yds
farther than a C34. I am sceptical of the claim for any 38' cruising
monohull of "8-9 knots consistently in moderate winds." Discreet Charm, C38
#50, will do 7.5 to windward (GPS) in 18-20 knts wind, no currents, under a
110% jib. Same wind on a beam reach gives 8 to 9 kts, on a good day. We have
clocked 15 kts downwind in 25 kts wind with our asymm spinnaker.  These were
white knuckle experiences, crazy, and scary; we aren't racing people.
Spinnaker on a pole with several skilled crew would probably do better. 
    Listen to the racers for max speeds.
Regards, Don

PAUL NOTTE wrote: 

Perhaps Kerry of littlebreeze will send you some picts of his cat 38 in
moderate wind .. How bout it Kerry?

----- Original Message -----
From: w humphrey  <mailto:hump5776 at yahoo.com> <hump5776 at yahoo.com>
Date: Thursday, July 9, 2009 6:12 am
Subject: [C38] Boat Speed
To: listserve at catalina38.org

> Hello, I am a new user of the listserver and an owner of a 34 
> Catalina. I have heard that the 38 is a fast boat and there may 
> be a possibility that I may purchase one in the near future. My 
> question is: how fast do these boats sail normally. Do owners 
> really see 8-9knts consistently in moderate winds. I am in the 
> great lakes and see 5-6.5 boat speed as an average with winds 10-
> 20 and sometimes 7 or a bit more in 20+. The reason I am 
> considering a 38 is for more speed so any realistic real 
> world experience would be appreciated, including performance in 
> lighter winds.
> Thanks, Bill 
> 
> 
>       

 





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-- 
Donald R. Strong
Professor
Section of Evolution and Ecology
University of California Davis
95616
530 752 7886

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