standup blocks on 23.5

[PSquirrel]

Has anyone replaced just the sheaves in the standup blocks. If so, could you post a description of or photo. One of mine just bit the dust.

I'm thinking of drilling the old one and bolting a new sheave in place. my concern is not having a "flush" side. If it gets whipped around on the deck a bolt head and nut could damage deck.

 

[Ralph Johnstone]

C'mon now.

We here at SBO all love a challenge but give us just a little bit of a hint here and include a picture.

Between when your boat was manufactured (when was that again ?) and now, hunter has changed the blocks they used by half a dozen times.

 

[PSquirrel]

this is the current H23.5 replacement for my boat. The sheave (nylon) has failed. My boat is a 97 H23.5.

I would like to salvage the unit by replacing the sheeve if possible. my boat has a 4-screw mount. I want to avoid drilling and taping. Been there, done that, nervous as hell, got lucky on another repair.

 

[Ralph Johnstone]

At those prices, I see why you're trying to repair rather than replace.

Unfortunately, it looks like any repair job will greatly reduce the strength of the block unless it's only to be used for a flag halyard.

Sorry I can't offer anything more optimistic.

 

[kloudie1]

These guys have shelves for replacement.i have done a few successfully. Measure carefully after drilling the axle pin. Some have a bushing, some don't. Use an acorn nut and cut the bolt flush with the nut when replacing. Once the pin is tapped out, the side plates can be rotated a little if necessary.

Delrin Sheaves

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[Ralph Johnstone]

I have eight of these little buggers of differing brands on the base of the mast and I'm not really coming up with anything worth writing home about. And the sheaves are not lasting forever.

Once the original pin is cut out, either by drilling or Dremel, I'm still stuck with looking for something smooth to go inside the the Derlin sheave ID. A threaded machine screw will rip up the ID of the sheaves quite nicely.

Measure carefully after drilling the axle pin. Some have a bushing, some don't. Use an acorn nut and cut the bolt flush with the nut when replacing.

Not clear what you are using for a pin here ? Is it a machine
screw ?

The only thing that's satisfying the mechanical requirements of the block, but will look like hell, is a long hex head bolt bolt with the OD of the SS bolt = the ID of the Derlin sheave and no threads under the head.

Cut the unthreaded section of the bolt 1/4" beyond the opposing cheek and drill and insert a cotter pin close to the cheek so the pin doesn't wander.

Looks like hell but it's mechanically sound and won't seize the sheave between the two cheeks when the nut is tightened.

Gotta go see the buddy with the lathe and see if we can come up with something better looking.

 

[PSquirrel]

well it looks like we have been slapped with the glove. A human designed these things, ergo! a human should be able to reverse engineer and replace a little wheel inside a metal frame.

My name is Inigo Montoya. They made something that can't be repaired. Aww shit.”

 

[Ralph Johnstone]

A human designed these things, ergo! a human should be able to reverse engineer and replace a little wheel inside a metal frame.

Easy, but at a considerable cost with a lathe to make the machined pins and a hydraulic press to compress the pins and form a retaining ring on the end of the pin.

Far cheaper to buy a new standup block.

 

[kloudie1]

Here is a picture of replacing the sheaves on the traveler end block. This shows the bushing that the sheave rides on This is a Schaefer unit as I suspect the stand-up block in question is. The replacement pin is a smooth sides one with threads at the end and not under the bushing although in this case, a fully threaded one would not make much difference in this application. Pin was removed by carefully drilling the flared end and driving out with a punch.. I did both ends of the traveler for around $25 and a couple of hours versus the 1.5 gazillion that Schaefer would have charged to rebuild or replace. Semi advanced DIY for sure but not a bad job ..

 

[caverun]

Just did this on my '98 Hunter 260. Schaefer block used for the centerboard uphaul. Purchased correct Schaefer Delrin sheave from West Marine ($$). Drilled out rivet on center pin. Sheave has a stainless bushing. Used a #10 SS pan-head bolt with nyloc nut- fit perfect. If you can find the right size clevis pin with cotter ring that works too.
SCHAEFER Delrin Sheave, 1/2" Max. Line Dia., 1-7/16" OD, 3/8" ID, 5/8" Width

 

[rgranger]

You can buy sheaves....

Just do a search for Schaefer sailboat block Sheaves and you will get a dozen pages similar to this one...



Then you need to size the bolt that goes through the block an scheave... and cap the threads with one of these.

to avoid a spot for your lines to snag.

To search for the cap, try using "nut cap" or "acron cap".

 

[Ralph Johnstone]

This shows the bushing that the sheave rides on

with threads at the end and not under the bushing although in this case, a fully threaded one would not make much difference in this application.

Beautiful. The bushing is what saves the day.

I wonder if mine would be so forgiving if/when a sheave should need to be replaced. Eventually I will get to see what the inside of a Rutgerson Sweden block looks like.

Hey, maybe they'll even have a selection of repair parts for their blocks as well. Just about the same time that pigs learn to fly.

Thanks for the explanation of how to repair a Schaefer .

.

 

[PSquirrel]

Thank you all for the input on this. Kloudie, I appreciate the photo. Seeing the bushing makes a threaded bolt a possibility. My reluctance is the bolt / machine screw head acorn nut. I can see scuffing and some minor chipping in the area where my standup block gets whipped about and contacts the deck. I fear an acorn nut slamming into it could cause greater damage.

 

[Ralph Johnstone]

I can see scuffing and some minor chipping in the area where my standup block gets whipped about and contacts the deck.

Do you mean when/if the line in the block fails. Normally, when the line is tight and in one piece, he block is motionless due to the tension and regardless of the sea state.

 

[kloudie1]

A dab of 5200 on the bolt head/end and a soft cap?
Amazon.com : rubber cap for bolt end
Less expensive than a new stand-up for sure..

 

[PSquirrel]

Ralph Johnson,

I'm a single hander. Things get a bit wild in stiff winds, hoisting and tacking.

 

[Stu Jackson]

Ralph Johnson,

I'm a single hander. Things get a bit wild in stiff winds, hoisting and tacking.

I'm NOT Mr. Johnstone, but I can spell his name correctly.

I, too, singlehanded my Catalina 22 and C 25 for 15 years. Stiff winds on SF Bay. I ran the halyards both back to the cockpit via standup blocks. Halyards should be under load so, as Ralph says, the blocks shouldn't be flopping about. Ever.
I have no idea what tacking could possibly have to do with standup blocks. Could you perhaps explain, please?

 

[PSquirrel]

Stu,
Sorry for the faux pas on the name.

I'm not sure how halyard got introduced to the thread. Let me clarify the location and use.

My SUB's are located on both sides of the cabin top. The jib sheets are lead through them. When hoisting the jib in windy conditions both sheets are slack. If the boat moves off from nose to wind and jib starts flapping the sheets have a tendency to whip the SUB's until I get them under control. Same thing when tacking. I try to keep tension on the leeward sheet until it backwinds against the mast pushing the nose through the turn then control the shift to other side. Sometimes it doesn't go smoothly.