N28 Masthead Sheave Size

[CharlzO]

Not sure if others had run into replacements, but when I purchased mine, two of the four were missing altogether and the PO (possibly the one before him too?) had just been using blocks on the outside for sail duties. Looking all over the place, I could find basically NOTHING that matched up, size-wise, offered as an off-the-shelf option. In my case, measuring the existing ones, left me with the following size:

2 3/4" diameter x 1/2" wide x 3/8" pin opening.

Enter Ballenger Spars, which actually has that exact size listed on his parts list (part number SHV2751612a) as an aluminum sheave. I ordered two, and will report back when they arrive, but I've had nothing but praise for them and expect nothing wrong. Current pricing as of today is $38 dollars. Not sure if that was each or for the pair, honestly lol. He just said, you need two? Ok, current price on those is... thirty eight. I was happy to have found them at all, and was like, yes yes, good, whatever, just gimme!

But in case anyone was wondering, that was the dimensions pulled of my 1975 N28.

 

[MitchK]

CharlzO,
I am in the process of replacing the sheaves in the masthead in my 1982 N28. If your masthead is the same as mine, you may want to check your dimensions carefully. One of the reasons I took the mast down was because the halyards did not run through the masthead smoothly. There seemed to be excessive friction on the halyards. What I discovered when I got it down, and started examining things is that the forward sheaves were not machined for 3/8 line. It appeared to be a cable style groove, and the halyards did not fit down into the grove very much and were rubbing against the forestay tang. You could see where the lines had polished the back side of the tang. The front sheaves in mine measure 2.6". I will be making the replacements 2.75", and cutting the groove for the line the proper shape for the 3/8 line. Now on the rear, the sheaves were different than the ones on the front. They measured 2.9" and were made of a different type of plastic, and were badly degraded. I will be using black Delrin (acetel) plastic to make the new sheaves. I have been considering making them with bronze bushing pressed in, but the original ones didn't have bushings, and they seem to have lasted a very long time. Anyway, it will be interesting to hear your report on how your new sheaves fit.

Mitch

 

[CharlzO]

The two I had in mine were on the rear of the masthead - the fronts were missing completely. Mine however, were that composite material from back in the day, with a simple V-groove instead of anything wire related. I'll be taking pictures Saturday when I get there. Ballenger sent out my replacements on Wed, so I'm interested to see how they go. Assuming I can find the pin that came from it originally. I'll post up a picture of everything as it sits now, in an hour when I'm home.

 

[CharlzO]

To give an idea, this is how the masthead currently sits (well, minus that I took the sheaves out that were in it in this picture - the cotter pin is showing through the sheave pin). Basically a previous owner re-rigged using the spinnaker bale for a block for the head sail, and added some little block to the rear for the main. Workable, yes, but I'd like to get it back into proper order before it goes back up.

The original sheaves are this style (not mine exactly, but the same kind):

 

[jssailem]

Here is an option that helped me with my refit.
http://www.zephyrwerks.com/

 

[CharlzO]

They were on the short list of options, as they would make them to spec instead of having to find something "close enough". Ballenger came in at $10 per, less, and I was a real fan after picking up my hinged mast plate from them for my previous boat. Turnaround time was two days, from the day I placed the order until shipped, so I can't complain a bit. But Zephyr is a site that I do have bookmarked, since I'm sure this won't be my only need with this boat.

Though I won't lie, I've been half tempted to go buy a lathe, some round aluminum stock, and make a killing on e-bay! well, maybe not..

 

[MitchK]

CharlzO,
I had looked at Zephyr's sheaves, and if I did not have the old 9x20 lathe, I probably would have bought them from them. As it is, there are a few differences between your mast head and mine. Where your mast head fits inside your mast, mine fits over the outside of the mast. Otherwise, the mast heads appear the same. I do not know if you have a larger size mast than I do, or its a different model mast head, but they are different.

Now the sheaves are and interesting situation. I had two different size sheaves (fore and aft), they were made from different materials, and the grooves were cut differently. The fore sheaves appeared to be made for either a cable of a smaller line and were 2.76" diameter. The rear sheaves were cut for 3/8 line and were a larger diameter, almost 3". Anyway, I determined that 2.75" would be a good workable size and grooves .3" deep. Not exactly what a rope sheave should be, but due to the thickness, it worked out ok. The other thing I have discovered, is that I need to cut the grooves in the front sheaves about 0.1" deeper. The reason is that the line rubs on the middle top webbing, and still rubs on the back side of the forestay tang. Not as bad as before, but I do not want any rubbing. I have about 0.2" clearance between the line and the rear of the mast head, so I have a little bit of room to work with. I will have to make up a mandrel to cut the grooves deeper as they have already been parted off the base stock.

I have attached some pictures to show the original and current configuration of the mast head. There is additional mounts that will be reinstalled for the antenna and anchor light, but they are not in the pictures.

 

[CharlzO]

Thanks for those pictures, I'm already questioning whether I'll get the new ones to fit somehow properly or if what you've said will hold true and I'll regret the sizing. Since I didn't have originals on the one end, I never questioned the size and just assumed they were all identical. Might be an interesting development!

I'm heading up to the boat tomorrow afternoon, after the mail arrives, with or without the new sheaves. I'm launching the boat either way, so there's a chance it might go in the water as it sits with the bodged up rigging. Then again, my brother is anxious to haul me up the mast sometime, but I'm not sure how much I trust the fittings for that. I might just add mast steps at some point and replace things that way. We'll see how tomorrow goes!

 

[MitchK]

The rear sheaves can be most any reasonable size up to and including 3". Its the front sheaves that are the issue. You could actually fit 3" dia sheaves, but there will be issues with the line rubbing the top web and the back side of the rear stay tang. In reality, it probably does not matter, and in some regards its a benefit having the line rubbing on the web/tang. You do not have to worry as much about loosing the shackle end of the halyards up the mast, as it does not run smoothly. Personally, I do not like the line rubbing, and will be trying to correct it. Remember, the original halyards were 1/8 steel cable that transitioned to 3/8" line. Its when it was converted over to all line halyards that the interferences came into play. With the capabilities of the newer lines, you could go down to 5/16" and still be plenty strong. Of course, 3/8 is easier on the hands than 5/16. Please let me know how the new sheaves fit.

 

[MitchK]

I just reread what I wrote in my previous post. Its the front sheaves that has the clearance issue, not the rear. Anyway, I machined another pair of sheaves, this time making the groove depth 0.4" (of still 2.75"), and they fit perfectly. A little more side wall height than I would have liked, but no clearance issues with the web and just the slightest touch of interference on the tang. All in all, I think it will work out well. It will be interesting to see how the sheaves form Ballinger fit. An interesting side note, from what I have read, it appears the mast on my boat was made by Lefiell in California. They are still in business, and according to their web page, still manufacture some parts for their masts, including replacement sheaves. Here's a link to their website.

http://www.lefiell.com/2marine_main.html

Mitch

 

[CharlzO]

Very interesting site, and great info. I don't think I've ever come across it, even in searches, so that's handy info to bookmark. I did get mine in today, after the sun FINALLY came up. The Ballenger sheaves fit JUST barely in the front of the masthead. Looking inside, there's maybe 1/8" clearance between them and the bottom of the assembly, and about as much on top also. The halyards in place, and I want to say they feel like 3/8, fit fine, without any rubbing (after I flipped the topping lift over so the little clamp wasn't catching on anything). They pull smooth from top to bottom, and no binding or anything I can detect. I did realize that I do need to fashion a divider in very short order between now and Wednesday - it was way too windy today to launch and step the mast, so that's been pushed off. But I realized when I put everything in there that I have no way to keep them together, other than gravity holding the lines down in the sheaves. Now it might not be an issue ever (I don't recall my Ex26 having any either) - BUT, It could also mean a jammed halyard at the worst time. It's curious how much left-right play there is inside though. I would guess there's a good 3/8" gap total? As you mentioned earlier, it looks like the same masthead. But be darned if this thing doesn't seem a might bit larger. I mean, the mast on mine has got to be a good 6" x 10" in dimension? I meant to measure and forgot, but it's definitely hefty. I guess the question is just going to be what to make it out of, and how thick. I used to have a sheet of ABS plastic that probably would've worked fine, if I could remember what I did with it!

Just for kicks, here's a picture of the finished masthead. Granted, I have to tighten the bolts, mount the windex, and the grommet for the VHF has been fixed, as well as raising the anchor light up to get it up from the base of the antenna which would block a giant swath of light. But I wanted everything mounted and in place before I left today to get an idea. And frankly, this is just getting things in working order, no idea if half of it is even correct!

EDIT: Just caught something on their site: It appears all their mast sections they have, at least listed now, are all with an internal Main groove. Obviously could've been just something they no longer offer, it could be a different mfr for my rig at the time? Or, it could be something that someone had replaced at some point with something they could get their hands on, cut it down to length, and called it good? I should've measured around the mast step to make sure it actually fits lol

 

[CharlzO]

Oh, also for reference, here's the new sheaves from Ballengers:

 

[CharlzO]

To follow up, I ended up making a half-divider. The new sheaves have no noticeable gap between them, and being close enough to the top of the masthead, the halyards aren't likely to move off those. But the originals in the aft of the assembly, had a 3/16" gap between them. I found remnants of what appeared to be an original divider disc floating around. What I did (for better or worse) was stopped at Walmart, and picked up a plastic clipboard for about 4 dollars, that was about 1/8" thick. I cut it to fit the rear "half" of the masthead, correctly angled. I cut a slot to fit over the pin, and popped the top of the masthead off, slid the divider down into place, and voila! Works perfect, it's not exposed and all the edges are rounded off just to be safe, and the halyards can't go anywhere now. Can't see it from the cockpit anyway so who cares what it looks like.

 

[MitchK]

Looks like you are well on your way to getting the masthead sorted out. I saw where you had got her back in the water over on the facebook page. I did notice the masts on Lefiell's web page do not look the same as our masts with the external sail slug slot. I have seen pictures of both style masts on various Newports. I have not seen any other mast company that has anything close to the profile of out masts. It may well be a different manufacturer, I really do not know for sure. I have seen various postings that said Lefiell made the masts for Newports. with a little bit of luck, I plan on re-stepping my mast on 5/12. Weather permitting, and I can get everything done between now and then. I have to replace the steaming light on mine, as the glass lense is cracked, and I have not been able to find a matching replacement. I ended up ordering a Forespare ML-2. Which is the combination steaming/deck light. I ordered the LED version. It should be here early next week.
Again, she looks great.

 

[CharlzO]

One thing that caught me by surprise was just how low the steaming light was to the deck. Most of the boats I've seen, have been up near, spreader height. Oh, funny story, remember how I said I needed to tighten the bolts? Guess what I quite literally forgot to do until just when we hooked the sling to step it? There's a reason I kept my tools on the boat!

 

[jssailem]

Good Catch @CharlzO . The very reason I keep a tool box and make a “Pre Splash” List of things to do and to check before and then in the water.

Checklists are not for sissy’s. They are so you do not forget a critical issue. Like leaking around thru hulls or stuffing boxes.