Measurers Corner

Measurer’s Interpretations and Recommendations

Topic:Deck
Question:May the backstay sheave be a Harken 310?
ID Number:000008
Date:2007-12-19
Short Answer:Yes 
Answer:A sheave to turn the backstay pennant is permitted. Sheave must be gasketed to be as watertight as practical. The fitting from the builder seems a better match for bulkhead water integrity then the Harken part. It is also important to use a "keeper pin" (see image). The Shields backstay casting is installed with four bolts as opposed to the Harken 310 which only accepts two fastenings and therefore cuts the load spread on the deck in half. See 1996 letter on this topic at (Class Rules - Appendix V) http://www.shieldsclass.com/bluebook/section.php?Section=A#A5 
Section:§IV-2.8 
Image:
Status:Affirmed
Action Date:2008-07-29
Sat Oct 19 10:48:03 2019
DateNameComment
2008-04-03Richard RobbinsThis was discussed by the Technical Committee (3/12/2008) and agreed that best fitting is the current design from Cape Cod Shipbuilding but other designs have been implemented and other designs should be allowed. The following is the proposed interpretation: The preferred and recommended fitting for the backstay turning block is the part manufactured by Cape Cod Shipbuilding called 'Backstay Deck Casting chrome plated bronze w/ sheave (B23)'. This current design includes 4 mounting holes, a turning sheave, keeper pin and a gasket nut. Other combinations of parts may be used as long as they are of equivalent strength and are gasketed to be as watertight as practical.
2008-07-30Richard RobbinsAdopted by Governing Board July 29, 2008. See July, 2008 Version of Rules.
2010-10-22Richard RobbinsFrom Webmaster: Please don't use this site for unrelated links. We have no desire to exchange links. Any post that is not related to Shields sailing will be discarded. PLEASE DON'T WASTE MY TIME (or yours) TRYING TO POST UNRELATED ITEMS.