Mast base blocks SWL 850 kg and 6 mm clevis pin

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   I have read with great interest a number of old threads about the need to replace the original Lewmar Synchro 60 blocks at the mast base. 
Power from our winch would be ~25 x 40 = 1 000 kg, block changing line direction of 90 degrees x 1,41. Total theoretical max load on the mast base block roughly 1400 kg then tension is coming from the winch with the strong captain at the handle.

Wait a second, on our yacht do we have Spinlock XAS clutches, I do assume it is the model supporting 6-12 mm ropes. According to Spinlock specification does it support load 280-575 kg and I have never noticed that the clutches has lost the grip so the peak load should have been lower than say 600 kg at all time. The load on the block might not be as high as the theoretical max load from the winch.
Most likely that the mast base block would have managed at max 600 x 1,41 ~ 850 kg load.

I don't want to drill through the mastcollar pin to increase the diameter to support larger clevis pins, another options is to during winter to swap mastcollar pins supporting 8 mm clevis pin.....
So I scanned through technical specification of blocks from:

Ronstan, could not find any with 6 mm clevis pin (only 8 mm) 
Barton, could not find any with clevis pin
One possible workaround could be to use a clevis adapter but that add extra height so if the line is hidden by GRP on route to the cockpit that could be a showstopper 
Lewmar Synchro 60, SWL/BL 800 kg/1600 kg skipped due to suspected low quality not fulfilling vendors specification 
and Synchro 72 SWL/BL 1200/2400 kg do not by default have 6 mm pin (and same unexisting trust that the block can cope with the load in the specification) 
Wichard block Sheave Dia 55, fixed head with clevis SWL/BL 720/1200 kg (Wichard have clevis adapters 5-8 and 6-10) 
Harken 6095 max line 16 mm / SWL 750 kg,  6096 max line 10 mm / SWL 748 kg, 6105 max line 10 mm / SWL 748. ESP blocks with sleeve bearings.
3042 max line 10 mm / SWL 750 kg (strange for a Black Magic block) 
Schaefer M66-20, fork width 12 mm, 6 mm clevis pin, SWL 770 kg 
Rutgerson B300601BF12, weight 183 gr, did I have problem to locate technical specification regarding support of 6 mm clevis so I contacted the vendor. After my verification question due to difference between emailed info and there web page did I get the SWL value of 850 kg . Sleeve bearings.
Price ~25 euro .
Rutgerson stand-up spring for 500 series cost 5 euro 
Garhauer 30-LSUS SWL 900 kg, weight 255gr. 
Price ~55 Euro Delrin ball bearings 
Garhauer 40-LSUS SWL 1270 kg, weight 313 gr
Price ~80 Euro Torlon ball bearings
SUMMARY of blocks designed for 6 mm clevis pin

SWL of 850 kg for 25 euro
SWL of 900 kg for 55 euro
SWL of 1270 kg for 80 euro

Rutgerson table below is the correct one, B300601BF12 would fit to our 342, mast collar pin diameter 12 mm and 6,35 mm holes for the clevis pin.
If someone prefer a swivel block there is another version called B300601BT ( I do recommend a fixed one due to that the mast and the organizer are fixed so there is no need of a swivel as I see it).
Diameter of mast collar pin is related to the mast profile, we have I330
http://www.sparcraft-us.com/us/technical_support/technical_brochures/ocean_range/fichiers/deck_collar.pdf

Below is the table from Garhauer

Clevis 6,3 mm
Fork width 15-16 mm
Order from the Scandinavian retailer needs to be done via email due to that 40-LS US is not listed in the web-shop.

Edited by skipper - 28 May 2012 at 13:40

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skipper Members Profile Send Private Message Find Members Posts Add to Buddy List Vice Admiral Joined: 16 February 2008 Location: Sweden Status: Offline Points: 825	Post Options Post Reply Quote skipper Report Post Thanks(0) Quote Reply Topic: Mast base blocks SWL 850 kg and 6 mm clevis pin Posted: 14 June 2011 at 17:03
	I have read with great interest a number of old threads about the need to replace the original Lewmar Synchro 60 blocks at the mast base. Power from our winch would be ~25 x 40 = 1 000 kg, block changing line direction of 90 degrees x 1,41. Total theoretical max load on the mast base block roughly 1400 kg then tension is coming from the winch with the strong captain at the handle. Wait a second, on our yacht do we have Spinlock XAS clutches, I do assume it is the model supporting 6-12 mm ropes. According to Spinlock specification does it support load 280-575 kg and I have never noticed that the clutches has lost the grip so the peak load should have been lower than say 600 kg at all time. The load on the block might not be as high as the theoretical max load from the winch. Most likely that the mast base block would have managed at max 600 x 1,41 ~ 850 kg load. I don't want to drill through the mastcollar pin to increase the diameter to support larger clevis pins, another options is to during winter to swap mastcollar pins supporting 8 mm clevis pin..... So I scanned through technical specification of blocks from: Ronstan, could not find any with 6 mm clevis pin (only 8 mm) Barton, could not find any with clevis pin One possible workaround could be to use a clevis adapter but that add extra height so if the line is hidden by GRP on route to the cockpit that could be a showstopper Lewmar Synchro 60, SWL/BL 800 kg/1600 kg skipped due to suspected low quality not fulfilling vendors specification and Synchro 72 SWL/BL 1200/2400 kg do not by default have 6 mm pin (and same unexisting trust that the block can cope with the load in the specification) Wichard block Sheave Dia 55, fixed head with clevis SWL/BL 720/1200 kg (Wichard have clevis adapters 5-8 and 6-10) Harken 6095 max line 16 mm / SWL 750 kg, 6096 max line 10 mm / SWL 748 kg, 6105 max line 10 mm / SWL 748. ESP blocks with sleeve bearings. 3042 max line 10 mm / SWL 750 kg (strange for a Black Magic block) Schaefer M66-20, fork width 12 mm, 6 mm clevis pin, SWL 770 kg Rutgerson B300601BF12, weight 183 gr, did I have problem to locate technical specification regarding support of 6 mm clevis so I contacted the vendor. After my verification question due to difference between emailed info and there web page did I get the SWL value of 850 kg . Sleeve bearings. Price ~25 euro . Rutgerson stand-up spring for 500 series cost 5 euro Garhauer 30-LSUS SWL 900 kg, weight 255gr. Price ~55 Euro Delrin ball bearings Garhauer 40-LSUS SWL 1270 kg, weight 313 gr Price ~80 Euro Torlon ball bearings SUMMARY of blocks designed for 6 mm clevis pin SWL of 850 kg for 25 euro SWL of 900 kg for 55 euro SWL of 1270 kg for 80 euro Rutgerson table below is the correct one, B300601BF12 would fit to our 342, mast collar pin diameter 12 mm and 6,35 mm holes for the clevis pin. If someone prefer a swivel block there is another version called B300601BT ( I do recommend a fixed one due to that the mast and the organizer are fixed so there is no need of a swivel as I see it). Diameter of mast collar pin is related to the mast profile, we have I330 http://www.sparcraft-us.com/us/technical_support/technical_brochures/ocean_range/fichiers/deck_collar.pdf Below is the table from Garhauer Clevis 6,3 mm Fork width 15-16 mm Order from the Scandinavian retailer needs to be done via email due to that 40-LS US is not listed in the web-shop. Edited by skipper - 28 May 2012 at 13:40
	Cheers, Skipper Former owner of Hanse 342 2005 (Sparcraft mast, white hull, wheel steering, deep draft keel, short rudder)

Peter-Blake Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral of the Fleet Joined: 04 March 2008 Status: Offline Points: 2471	Post Options Post Reply Quote Peter-Blake Report Post Thanks(0) Quote Reply Posted: 14 June 2011 at 17:09
	most of my lewmar synchro blocks broke in the first season. Now i have the ones from Harken (2 Years now) and no problem so far. Interesting is that the Harken do have a lower SWL. But i am sure the synchro never reach the SWL as mentiones from Lewmar! Edited by Peter-Blake - 14 June 2011 at 17:19
	Blake 370

greyghost Members Profile Send Private Message Find Members Posts Add to Buddy List Captain Joined: 02 November 2005 Location: United States Status: Offline Points: 151	Post Options Post Reply Quote greyghost Report Post Thanks(0) Quote Reply Posted: 14 June 2011 at 17:38
	It may well be that these Lewmar blocks can reach their rated loads in a controlled test situation. However, in the real world, they clearly do not hold up. In the real world, these blocks can come under load before they are optimally aligned with it, resulting in damage or complete destruction.. I have found that all too often the line can jump the sheave and, with the soft stainless cheeks of these blocks, the line can get jammed between the sheave and the cheek of the block. When this happens under high loads, the block simply explodes. Cheers, Doug
	Cheers, Doug Grey Ghost 342 #405

Yeoman Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Joined: 31 May 2007 Location: Hamble Status: Offline Points: 384	Post Options Post Reply Quote Yeoman Report Post Thanks(0) Quote Reply Posted: 14 June 2011 at 18:02
	Hi Folks, Lewmar have helped the problem by offering their 72mm block with the smaller pin now. You can ask a lewmar dealer for it specially for Hanse. Seems a good solution Cheers Phil

Peter-Blake Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral of the Fleet Joined: 04 March 2008 Status: Offline Points: 2471	Post Options Post Reply Quote Peter-Blake Report Post Thanks(0) Quote Reply Posted: 14 June 2011 at 18:12
	Do you have a part number Yeoman?
	Blake 370

Brufan Members Profile Send Private Message Find Members Posts Add to Buddy List Rear Admiral Joined: 16 December 2010 Location: Belgium Status: Offline Points: 672	Post Options Post Reply Quote Brufan Report Post Thanks(0) Quote Reply Posted: 14 June 2011 at 18:14
	Things are changing. Now masts & booms are provided by Selden as well as the footblocks. But mainsail sheetblocks are still from Lewmar synchrorange. See photo of freshly delivered H 355 (mastfoot starboard side)
	Bruno hanse 355 - 57 S/Y Spicy Ginger White hull, 2 cabins, Volvo D1-30, Selden rig, removable mainsheet track system, Simrad (now B&G)-Jefa autopilot.

samuel Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral of the Fleet Joined: 26 December 2004 Location: United Kingdom Status: Offline Points: 2770	Post Options Post Reply Quote samuel Report Post Thanks(0) Quote Reply Posted: 14 June 2011 at 18:23
	I have Barton blocks on some of my rigging have you tried them for detailed specs? Cheap & fairly strong Daydream Believer
	Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex

skipper Members Profile Send Private Message Find Members Posts Add to Buddy List Vice Admiral Joined: 16 February 2008 Location: Sweden Status: Offline Points: 825	Post Options Post Reply Quote skipper Report Post Thanks(0) Quote Reply Posted: 14 June 2011 at 20:16
	Car manufactures do from time to time recall sold cars to fix a common important function even if the car is over 2-3 years old. My expectation is that "Quality people in yachting" realize that they have done a design fault and therefore do they send out new blocks aimed for the size of the sold yacht as part of there after-sale support, free of charge! According to MarcoC web page for a Swedish H 370 called S/ Älva http://www.wesailhanse.se/370_mastfootblocks_en.htm is the Lewmar order number L29927222. Edited by skipper - 19 June 2011 at 11:55
	Cheers, Skipper Former owner of Hanse 342 2005 (Sparcraft mast, white hull, wheel steering, deep draft keel, short rudder)

Yeoman Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Joined: 31 May 2007 Location: Hamble Status: Offline Points: 384	Post Options Post Reply Quote Yeoman Report Post Thanks(0) Quote Reply Posted: 15 June 2011 at 08:57
	Hi Peter, I am afraid I don't sorry Kind regards Phil

MarcoC Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral Joined: 23 April 2009 Location: Sweden, Stockh. Status: Offline Points: 1617	Post Options Post Reply Quote MarcoC Report Post Thanks(0) Quote Reply Posted: 15 June 2011 at 15:03
	You can find everything about the masfootblocks including the part number here http://www.wesailhanse.se/370_mastfootblocks_en.htm I appologize that I have hadnt time to translate it to english yet but the pictures will tell the story. Otherwise contact me and I tell you more. Edited by MarcoC - 15 June 2011 at 15:06
	"Älva" Hanse 370#671 Stockholm, Sweden www.wesailhanse.se big wheel, deep draught iron keel, 3 cabins,Yanmar 3JH4E, Sparcraft rig.



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