Mast Block Replacement

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   I read the old posts about replacing the Lewmar mast base blocks but didn’t find my answer. The posts coming up from my mast collar seem to accommodate 8 mm pins and most of the Harken blocks I’m interested in are 5/16”. I tried and they didn’t fit. I’m wondering if I can ream out the opening? It seems to me that I only need to remove 3/1000”. Anybody do this? Wondering if this can materially affect the strength of the post?

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
Issywa Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 13 April 2022 Location: Seattle Status: Offline Points: 143	Post Options Post Reply Quote Issywa Report Post Thanks(0) Quote Reply Topic: Mast Block Replacement Posted: 02 March 2023 at 23:27
	I read the old posts about replacing the Lewmar mast base blocks but didn’t find my answer. The posts coming up from my mast collar seem to accommodate 8 mm pins and most of the Harken blocks I’m interested in are 5/16”. I tried and they didn’t fit. I’m wondering if I can ream out the opening? It seems to me that I only need to remove 3/1000”. Anybody do this? Wondering if this can materially affect the strength of the post?

Dogscout Members Profile Send Private Message Find Members Posts Add to Buddy List Captain Joined: 10 July 2017 Location: Wandering About Status: Offline Points: 207	Post Options Post Reply Quote Dogscout Report Post Thanks(0) Quote Reply Posted: 02 March 2023 at 23:55
	So I replaced the ones on my 430 with Rutgerson blocks. I dont imagine that taking .003 off of the pin would weaken it too much.
	Adventure awaits

Issywa Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 13 April 2022 Location: Seattle Status: Offline Points: 143	Post Options Post Reply Quote Issywa Report Post Thanks(0) Quote Reply Posted: 03 March 2023 at 05:45
	Well I like the idea of not having to modify the posts. After checking the Rutgerson website, it looks like there are two viable options - either the 60 mm or the 80 mm sheave with working loads of 1150 and 2000 kg respectively. I'm inclined to upsize and go with the larger block but wondering what you did?

Dogscout Members Profile Send Private Message Find Members Posts Add to Buddy List Captain Joined: 10 July 2017 Location: Wandering About Status: Offline Points: 207	Post Options Post Reply Quote Dogscout Report Post Thanks(0) Quote Reply Posted: 04 March 2023 at 14:28
	Im using the 60 mm blocks at the mast base. A few of the original Lewmar blocks on my 2007 430e have failed and so far I have replaced all of the mast base blocks. I have bought new 80mm blocks for the mainsheet and will replace them next. On my Atlantic crossing one of the mainsheet blocks came apart and so did a sheeve from the port side line organizer. Lots of sheeves/blocks getting replaced now. Mast top sheeves were replaced last September when I had the rigging done. The Lewmar blocks have spent 15 years in the sun so I suppose that was long enough.
	Adventure awaits

Issywa Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 13 April 2022 Location: Seattle Status: Offline Points: 143	Post Options Post Reply Quote Issywa Report Post Thanks(0) Quote Reply Posted: 04 March 2023 at 15:39
	Was it a new Rutgerson block that failed during your Atlantic crossing, or one of the older Lewmars? Wondering if you damaged your main halyard like mine? In the photo, you can also see the block on the reefing line has failed. Definitely time to replace all the blocks. I figure I'm about a year or so behind you in the various replacements.

Dogscout Members Profile Send Private Message Find Members Posts Add to Buddy List Captain Joined: 10 July 2017 Location: Wandering About Status: Offline Points: 207	Post Options Post Reply Quote Dogscout Report Post Thanks(0) Quote Reply Posted: 04 March 2023 at 20:55
	It was one of the Lewmars that broke during the crossing. Port side mainsheet block attached to the cabintop. Most of my Lewmars had pieces of that plastic side flange broken off although a few look fine, I am certain that the plastic is weak. So what is attached to the bottom of the pin for the vang?
	Adventure awaits

Issywa Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 13 April 2022 Location: Seattle Status: Offline Points: 143	Post Options Post Reply Quote Issywa Report Post Thanks(0) Quote Reply Posted: 05 March 2023 at 05:04
	I couldn't find a good photo but I think its the block that turns the vang line back towards the cockpit. When I get back home from my ski trip, I'll take a pic. Any other shots you might be interested in?

Issywa Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 13 April 2022 Location: Seattle Status: Offline Points: 143	Post Options Post Reply Quote Issywa Report Post Thanks(0) Quote Reply Posted: 22 March 2023 at 01:53
	Sorry for the delay. Shot of my vang at the base of the mast. Also, I finally figured out why I was having issues fitting Harken blocks in the 8 mm post sticking up from the mast collar - the chandlery gave me a block with a 3/8" pin but told me it was 5/16". Anyway, I'm replacing the Lewmar blocks with the narrow collar style from Harken with a 75mm sheave and 5/16" pin.



Welcome to myHanse.com the forum for Hanse Yachts owners throughout the world.