CD 27 Working Load on Genoa Blocks?

Bob Owens · Post by **Bob Owens** » Apr 3rd, '08, 20:51

Can anybody give me an approximate minimum safe working load I should have in mind in shopping for new blocks for my 140% genoa sheets. Believe it or not, I have still been using what I think must be the original CD snatch blocks, which have 2" dia. sheeves. They carry no name or number code. The manual says original 27 and 28 genoa blocks were Schaefer 07-83, but I can't correlate that to model numbers on Schaefer's current products. These blocks get very expensive fast as one moves up the size scale, so I want to avoid overkill. Thanks.
Bob

Kurt · Post by **Kurt** » Apr 3rd, '08, 22:03

As I recall, the CD27 has 1" t-track...take a look at the following URL...or maybe you could be patient and watch eBay for a better deal?
http://schaeferhardware.com//detail.aspx?ID=1281

marilou · Post by **marilou** » Apr 4th, '08, 06:49

I believe Garhauer Marine has one for less than $50.00. You might, also, consider car with snatch block.

Stan W. · Post by **Stan W.** » Apr 4th, '08, 08:36

MY CD 28 is a '79 and it still has its original genoa sheet blocks. They are Schaefer 5 series, not 7 series, and they work fine. If Cape Dory started specifying 7 series blocks, I think it must have happened sometime after my boat was shipped.

Wichard has published load charts for most Cape Dorys, including the 27.

http://www.wichard-usa.com/Boat%20pages ... 20page.pdf

Bob Owens · Post by **Bob Owens** » Apr 4th, '08, 11:38

Just what I needed, Stan. Thanks very much.
Bob

Warren Kaplan · Post by **Warren Kaplan** » Apr 4th, '08, 17:17

Here is something that I found quite useful when picking new hardware that would be under load. Scroll down and look at it all. You may be able to calculate the loads on your blocks depending on the sails you are using.

http://www.mauriprosailing.com/Harken/h ... rmulas.htm

mgphl52 · Post by **mgphl52** » Apr 5th, '08, 08:56

Here's a spreadsheet I built from scrounging PHRF info & Harken's formulas with data set for a "cruising-mode" CD28.
http://sv-kayla.org/KAYLA/misc/Raw_PHRF ... s_CD28.xls

Just adjust the BLACK numbers as needed and the BLUE numbers will calculate for you. If you do not have a excel or OpenOffice (which is FREE!), you can upload this into a Google account (also FREE!).

Hope it helps!

The Cape Dory Board

CD 27 Working Load on Genoa Blocks?

CD 27 Working Load on Genoa Blocks?

This be the one...and yes, inflation has taken it's toll

Possible Alternative

Immensely Helpful

Harken Load calculations

Raw PHRF calculation (approx...) & sheetload spreadsheet