Josh, Good to know!
Joel <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Virus-free. www.avg.com <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> On Thu, Jan 25, 2018 at 10:51 AM, Josh Muckley via CnC-List < cnc-list@cnc-list.com> wrote: > I reached out to the internet for some more info on sheave and rope > sizes. I stumbled upon a Marlow website which was loaded with technical > details. They had a FAQ section and then a submit your own question > section. Here is their answer. > > We normally say the ideal groove is one that has a width around 10-15% > bigger than the rope diameter and has a semicircle profile. The reason for > this is that it supports the rope's shape without causing abrasion or > distortion. If the groove is too small then the rope rubs against the > sides when entering and leaving the sheave and is squeezed, this causes > abrasion and can accelerate rope wear. If the groove is too big it allows > the rope to distort and flatten as it enters the sheave, this will cause > more internal abrasion and so accelerate fatigue. > > V grooves are normally used where the rope, or wire, is driving the sheave > (or vice versa). In this case the 'V' serves to increase the friction > between the rope and the sheave at the expense of rope life. > > I hope this explains things. > > Regards, > Paul Dyer | Technical Manager > WWW.MARLOWROPES.COM > > > So there you have it. As previously discussed I'll be having the sheaves > made with a 1/2" groove. I'm willing to trade off slightly reduced service > life for the versatility of a larger groove. Hopefully this helps someone > else. > > Josh Muckley > S/V Sea Hawk > 1989 C&C 37+ > Solomons, MD > > > > On Jan 23, 2018 7:41 PM, <captain_j...@cox.net> wrote: > >> Josh, >> >> >> >> I use the term stopper as a generic for sheet stoppers, halyard stoppers, >> jammers, rope clutches, or almost any kind of mechanical cleat (except a >> cam cleat. I call those cam cleats). I have some really old Schaefer rope >> clutches that work just fine. They hold 3/8” or 10mm line well, 7/16” most >> of the time too. >> >> >> >> I don’t think there is any serious concern if the sheave is slightly too >> large. Yes, the halyard will be slightly flattened, as it will not be >> supported quite as well, but as long as the difference is only 1/8” or so, >> it’s not an issue. A serious mismatch (1/4” or more) might be cause for >> some concern, but it would be the long term damage from being repeatedly >> flattened and reshaped as the line runs over the sheave. >> >> >> >> Jake >> >> >> >> *Jake Brodersen* >> >> *C&C 35 Mk-III “Midnight Mistress”* >> >> *Hampton VA* >> >> [image: cid:image001.png@01D2F43E.567E4070] >> >> >> >> >> >> >> >> *From:* CnC-List [mailto:cnc-list-boun...@cnc-list.com] *On Behalf Of *Josh >> Muckley via CnC-List >> *Sent:* Monday, January 22, 2018 21:42 >> *To:* C&C List <cnc-list@cnc-list.com> >> *Cc:* Josh Muckley <muckl...@gmail.com> >> *Subject:* Re: Stus-List Masthead sheaves C&C 37+ >> >> >> >> Halyard stopper? What's that? Haha, no really what's that? Stopper >> balls? Or jammers? >> >> >> >> You're right though 3/8ths is almost too small for my winches. So >> smaller is pretty unlikely. But bigger might be nice, particularly if it >> becomes necessary to run the taper of a core to core eye splice. >> >> >> >> The 3/8ths sta-set I have for my spin halyard is almost too small at >> ~5000 lbs break strength. I really like to make sure my lifting rigging is >> sufficient for climbing standards. >> >> >> >> I guess my question is, is there any disadvantage to running smaller line >> in a big sheave. >> >> >> >> Josh >> > > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > > -- Joel 301 541 8551
_______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
