SailNet Community banner
  • SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

Adding a topping lift, or the heck with sheaves

8K views 32 replies 11 participants last post by  blutoyz 
#1 · (Edited)
Hey all! Any help on this one would be much appreciated and it really is a two part sort of thing where one answer may solve both issues.

We have the mast down on our M25 1981 and are doing some mantainance and additions. We want to add a topping lift and were looking at the mast head (right name?) where the lines, in this case just a main halyard, come up run through sheaves and back down. Here is ours.
Aft


Forward


First off, I think the sheaves that are already there need replacing. Can these just be purchased somewhere like Mcmaster Carr? How do you pull it apart to replace them? Sorry for the green question but I have never seen a connection quite like these. Look like giant rivets.

Also, if I want to add a topping lift, can I add additional ones or do I need to change out the whole top to add a space. How do folks handle that one? Could you just hang a block for the purpose? Where would you hang it that wouldn't mess with the sail. Sorry. I am gabby.

Any suggestions? Gotta add an outhaul too for our new fancy sail sitting in the box while my lakes are still frozen. But the work can really begin. Keel cable and bolts inspected today, battery back in and charged, connected back to solar, everything removed for an internal scrubbing, etc.

Here to show you we are in this for real, this is what is behind me right now. Two down, 5 to go plus the cockpit if we are inspired after the interior.


Thanks for any help. This is my first real project that I can talk about on here. I promise to take pics :D
 
See less See more
3
#2 ·
I can't tell from the pics how the sheave pins are attached. Pics from each side would help.

You don't need a block at the masthead for a topping lift. You can dead-end it at the top and put a block above the end of the boom. A line runs from the boom end through the block and back down to the boom, through a small cheek block and to a clamcleat if you want. The clamcleat can be anywhere on the boom - near the mast or at the aft end.
 
#7 ·
I will grab some pics of the sheaves from the side today. It doesn't appear obvious how they were attached. Great idea on running it the other way and dead ending at the mast instead. That would be easy comparatively.

Hi AlaskaMc
Just took a quick run outside to check my mast head and as I thought it is the same as yours. (I too have a Mac 25) My sheave blocks are just through bolted so just undo them and replace the sheaves and bolt them back in.
As for a topping , just forward of the backstay I have another bolt that goes through the masthead to which I added a block, ran a line through the block and down to the mast. After lifting the mast up I run one end of the line to the boom and the other end down the mast to a turning block to a deck organiser and then to a cleat on the cabin top. This works for me as I can raise or lower the boom from the cockpit. Hope this helps.
Anthony
Thanks for going and taking a look. I will need to go and check that when I take my pics. I don't think these are bolted but I will look again. If so, then this was the silliest question ever and should be easy to fix! My plan for the lift was exactly as you describe though as we wanted to have it for an extra halyard should we lose it up the mast. Great description! You don't have pics online anywhere do you?

Yes, absolutely replace those sheaves. Measure them, then look around for replacement sources. We replaced the sheaves from our Catalina 25 using the sheaves sold by Catalina Direct:. Their sheaves may work for you, too.

Regarding Brian's suggestion for the topping lift, if his description didn't make sense, check out the description and drawing here:
Topping Lift Kits from Sailcare
Makes perfect sense and thanks for the link. Diagrams are nice to see and part lists are handy to say the least. Thanks! I will check with Catalina as well on the replacement sheaves. I was thinking of delrin sheaves from Mcmaster-Carr and thought those would work.

Al,

consider a Boomkicker instead of a topping lift. Works along with your vang and about the same price as a topping lift kit. We love ours and we trailer every sail.

Don
My wife likes the idea of the book kicker too but can it be used to lift the boom out of the cockpit when at anchor? Looks like you would still have the boom at face level when at anchor. We spend many nights out on the boat so that was one of the goals of the lift.

Thanks everyone! I knew I could count on sailnet.
 
#3 ·
Hi AlaskaMc
Just took a quick run outside to check my mast head and as I thought it is the same as yours. (I too have a Mac 25) My sheave blocks are just through bolted so just undo them and replace the sheaves and bolt them back in.
As for a topping , just forward of the backstay I have another bolt that goes through the masthead to which I added a block, ran a line through the block and down to the mast. After lifting the mast up I run one end of the line to the boom and the other end down the mast to a turning block to a deck organiser and then to a cleat on the cabin top. This works for me as I can raise or lower the boom from the cockpit. Hope this helps.
Anthony
 
#4 ·
Yes, absolutely replace those sheaves. Measure them, then look around for replacement sources. We replaced the sheaves from our Catalina 25 using the sheaves sold by Catalina Direct:. Their sheaves may work for you, too.

Regarding Brian's suggestion for the topping lift, if his description didn't make sense, check out the description and drawing here:
Topping Lift Kits from Sailcare
 
#6 ·
You can make a topping lift kit for well under $100. Use dyneema (Amsteel) instead of wire for the fixed portion of the topping lift, it is much lighter and will blow out of the way of the sail when sailing. Even the smallest dyneema will be plenty strong.

A basic topping lift on a 25' boat is about 30' of 7/64" dyneema ($10) with a brummel splice on each end, a Harken 2698 T18 block at the bottom splice ($17), and 10' of 1/4" double braid running from the end of the boom ($7), up to the block, and back to a cleat on the boom. If you don't already have a cheek block and cleat on the boom you'll need to add them, but you can still do the whole project for well under $100. It makes a much better topping lift then the kit from Sailcare.

This is what I mean by the dyneema topping lift flies out of the way of the sail:


That photo was taken in 6 or 7 knots of wind.
 
#8 ·
When you are at anchor you can use the main halyard to lift the boom out of the cockpit. You should move the main halyard there anyway so that it doesn't slap against the mast and keep your neighbors awake at night.
 
#9 ·
We secure our halyard so that it doesn't do such a thing. Never heard of moving it to the boom for neighbor annoyance avoidance. But then we are in Alaska and the odds of a "neighbor" doesn't come up often. But banging lines drive me good and nuts too. Good idea. Any thoughts on the jib halyard? We just usually clip both to deck fittings we have to keep them off the mast and out of the way. But if it can do something useful too that would be nice. Thanks.
 
#10 ·
When I had a hank-on boat I would bring the jib and spin halyards to the bow pulpit, but anywhere away from the mast is good.

Almost every boat that I sail on uses the main halyard to support the boom when docked. It's the best way to lift the boom high off of the cockpit if you want to hang out in there. Most topping lifts (like the design that I described above) allow you to lift the boom up to a foot to support it while raising sail and to provide sail shape in extremely light air. They aren't meant to lift it farther.
 
#12 · (Edited)
Ok, this sounds easy (your plan for the topping lift and how to put it together) but I have a devil's advocate question; why not run it up the mast through a block and down to the top of the boom. This is how it is on the boats we have run in the past (newer/larger) so that it can act as an emergency halyard if needed. Why not just do this with dynema line. I am sure there is a good reason I just am new and not getting it.

EDIT: And one more question, if you are on a run downwind and want to adjust, isn't it a pain if the line is cleated on the boom vs in an organizer/clutch on the cabin top? Again, asking as I have never had one on my boat.
 
#17 ·
Ok, finally back to this one after diversions onto many projects that caused the masthead to be 28 feet above my head. But she is back down now and I need some help.

What the heck are these? Sorry if this is a total newbie kinda question but it doesn't look like any rivet I have ever used.


I have an exact match to this fitting on a destroyed old block and have tried drilling it out and punching out. Can these be removed so the sheaves can be replaced? Or do I have to replace the head piece.

What do you all think?
 
#18 ·
Drill out the end, punch out the pin and replace the sheave with a stainless bolt and locknut

Easy peasy lemonsqueazy

(Actually, it is a PIA but if you get sheave from a consignment shop it sure beats the big $$$ you would throw for a new masthead)
 
  • Like
Reactions: AlaskaMC
#19 ·
So that head in the first pic is just a rivet head? Drill out and tap out as you would a typical rivet? That is easy if so. Is that just a washer under the head?

Thanks! Then I would just replace with a SS bolt and locknut and a new sheave? That does sound easy!
 
#20 ·
I have used those delrin sheaves from McMaster to replace a sheave in my boom.
One nice thing about the delrin is I was able to easily adjust the shape of the sheave a bit by sanding the sides to make it "thinner" and a drill bit made the pivot hole slightly larger to fit my application.
So you don't need an exact fit but as close as possible given the sizes of delrin sheaves McMaster Carr sells.
 
#21 ·
Alaska,

I'm a little late to the party, but I have something to add: You should be using clevis pins and cotters to attach the halyard sleeves to the masthead. Nuts and bolts, even when using nylocks and locktite can work loose. The rigger's way is to use clevis - add SS washers to shim the pins to both relieve stress on the cotters and to prevent movement.
 
#22 ·
Thanks George. That is a good point and all the sheaves that are for my masthead come with the pins etc from Dwyer.

On the drilling end, WOW, these things are like nothing I have ever tried to drill out before. Any tips anyone? I flattened my punch just trying to get a dent to drill into. About to go grab an angle grinder to do it.
 
#23 ·
They are almost certainly stainless. You want new/sharp cobalt bits, low speed, cutting oil, and pressure so that you make progress on every blade rotation. If the bit just spins it will work harden the stainless and make it harder than a high speed steel bit.

I'd be drilling off the concave part of the pin. Once the head comes off (not much material to remove) you just use a pin drift to knock the pin out of the masthead.
 
#24 ·
Alaska,
Stainless is so much fun! Stainless is very hard so drilling generates a lot of heat and work tempers the steel. You need to buy a set of colbalt drill bits. Carbide will do in a pinch but will get dull. "normal" bits just get dull and won't cut SS. Use cutting oil to keep the work "cool" and well lubricated. Drill very, very slowly and use a lot of pressure on the drill. When done properly, the drillings should come out in "twists" If it is coming out in "chips", you are probably drilling too fast.
 
#25 ·
Done! But these are not pop rivets in the normal sense. I went down to get a grinder after little to no luck with my good bits and cutting oil. So, while picking up the grinder I show the little block with these on it to the salesperson. He had never seen such a thing and we hear a guy laughing behind us hearing us talk of drilling them out. He was a Navy machinist. He said he had ground off tons of these fittings before. They are a rivet of sorts but a custom make with a special press that puts them together. He said to grind the conclave side of the stud until the washer came off. Then tap out the head with a punch. He was right. Took about 30 seconds each.

The shafts on these are solid stainless and heavy. You would have a heck of a time drilling the "head" side of these as you will go through about a 1/4'' of material before you can do any good. The other side on the other hand is about a 16th and done.

Maybe you can drill these out, but after doing them I would recommend a grinder. These are definitely not pop rivets and are not going to drill out like one.

Now onto finding the sheaves to replace it. Thanks for all the help on this everyone.
 
#33 ·
Done! But these are not pop rivets in the normal sense. I went down to get a grinder after little to no luck with my good bits and cutting oil. So, while picking up the grinder I show the little block with these on it to the salesperson. He had never seen such a thing and we hear a guy laughing behind us hearing us talk of drilling them out. He was a Navy machinist. He said he had ground off tons of these fittings before. They are a rivet of sorts but a custom make with a special press that puts them together. He said to grind the conclave side of the stud until the washer came off. Then tap out the head with a punch. He was right. Took about 30 seconds each.

The shafts on these are solid stainless and heavy. You would have a heck of a time drilling the "head" side of these as you will go through about a 1/4'' of material before you can do any good. The other side on the other hand is about a 16th and done.

Maybe you can drill these out, but after doing them I would recommend a grinder. These are definitely not pop rivets and are not going to drill out like one.

Now onto finding the sheaves to replace it. Thanks for all the help on this everyone.
I just got back to this....
I should have been more clear. When I wrote "drill it out" I used an oversized bit to take off the mushroomed end and then knock the pin out. Safer than a grinder for the surrounding material...sorry

That is good advice on the clevis pin...it would be a real PIA if it dropped out
 
  • Like
Reactions: AlaskaMC
#26 ·
That is why I recommended drilling out the "tail" (concave) part of the pin. I've removed rivets like that with a drill and it worked just fine. A grinder also works, you just need a steadier hand to avoid marking up any of the surrounding metal.
 
#27 ·
You were right on going for the tail of the pin thats for sure. The grinder was really easy and all is well. Now I am shopping for sheaves. Oh joy, never knew how many different sizes there were out there. Mine is 1 3/8 OD, 1/4 ID, 9/16 wide, pretty specific and I actually just found them amazingly. Now I hope I can get them as we splash in two weeks time and there is still a pile to do.
 
#28 ·
If for whatever reason you replace those pins you drilled out with bolts, get bolts that are too long so that the part the sheave rides on is smooth (no threads). Then cut off the excess threads on the other side of the mast head. Most sheaves will have some kind of a metal collar that they ride on, but the threads on a bolt can still chew them up, so getting rid of the threads helps a lot.
 
  • Like
Reactions: AlaskaMC
#30 ·
A short length of ss shaft and drill for pins on both sides solves the thread problem.
Good points guys. But, I have already gone the pin route as suggested by George. In fact just got back from WM after having my wallet emptied and my credit maxed.

How is it that happens every time I enter that place? I feel woosy, don't remember exactly what happened, have a car full of stuff and my bank is calling me due to unusual activity. Well, that last one has stopped due to it being usual activity. :confused::p:eek: Truly, who cares, I have a big bag of stuff to go through. :laugher
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top