Repacing Masthead Sheaves

[ForeverDes]

Below are pics of my disassembled mast head.
I'd like to replace the sheaves, sheave bolt, spinnaker block/pulley(?), masthead 360 degree light, and maybe add a pulley in the back. I'm also going to replace the mast wiring since it has some significant chafing, so adding conductors is no problem.

So here are the questions:
Are the current sheaves sized appropriately for my halyards?
What material should I try to find for the new sheaves? Something with a bronze sleeve bearing? Aluminum, Delrin (sp?), or something else?
Can anyone recommend a good 360 degree LED masthead light? And do I need/want an integrated tricolor for the masthead?
The shrouds attach with tangs to the sheave bolt, is there anything wrong with this?
The fore-and-backstays pin to the toggles, and I plan to replace the pins and cotter pins. I already have stainless pins that fit, and I prefer cotter rings. Is there anything wrong with those at the top of the mast? Is there concern in cotter rings coming undone when they can't be easily seen?
Can anyone recommend a new spinnaker block?
Does anyone have a good suggestion for a new VHF antenna? I've never used VHF, and I have no idea what to look for. I have plans to eventually add an AIS transponder, so if I can prep for that now (with a 2nd coax perhaps) I'm more than happy to.
Does anyone see any problems I should be addressing that I haven't mentioned?
And finally, what else should I consider while I've got the masthead off?
p.s. My original plan was to replace the masthead assembly entirely, but after removing it, I really don't see any reason to. My halyards are all external, and I don't have room to add any, but I can't see that being a reason to throw out what I have now.

[ForeverDes]

My current sheaves are:
1/2" I.D.
4 1/4" O.D.
1/2" thick


and my halyards are 7/16"

[Benz]

Everything looks fine. Unless the sheaves are not working (elongated hole or whatever) why replace them? That material lasts forever.
Lopolight makes nice LED masthead units. If you're bothering to run wires, why not go tricolor?
I thought AIS could use the VHF antenna concurrently with the radio, but here I'm out of my depth, since I have neither.

[ForeverDes]

Originally Posted by Benz

Everything looks fine. Unless the sheaves are not working (elongated hole or whatever) why replace them? That material lasts forever.
Lopolight makes nice LED masthead units. If you're bothering to run wires, why not go tricolor?
I thought AIS could use the VHF antenna concurrently with the radio, but here I'm out of my depth, since I have neither.

I think AIS and VHF can work on one antenna with a splitter, but I'm not sure that's the ideal. But I also have no experience, hopefully someone will chime in that does.

As for replacing the sheaves, I don't know that it's necessary either, but while I have everything apart I want to at least look into it and see my options. There is some minor chipping around the edges of these sheaves that likely doesn't affect performance, but I'd hate to see my halyards wear excessively.

As for the tricolor light, cost seems to be the only inhibiting factor. I can't seem to find a decent tricolor/anchor combo light for less than about $250, and that seems a little excessive. However, it's also a (hopefully) one time cost, so it may be worth it. If I don't add it this year at least I'll have the 3 conductor wire in place for whenever I do add it.

[s/v Jedi]

If you want an antenna that can do both VHF and AIS then the Vesper is the most economical choice at $99

[ForeverDes]

Originally Posted by s/v Jedi

If you want an antenna that can do both VHF and AIS then the Vesper is the most economical choice at $99

Thanks! I'll look into it

[donradcliffe]

I have had a lot of trouble with LED tricolors emitting RF noise which really cuts the range of the AIS/VHF when they are on. Even ones that are sold as low/no emission. Check for interference by listening to a distant weather channel and turning the lights on and off before you put your mast up.

The sheaves look like they were designed for wire/rope halyards, but they should be fine for your 7/16 rope. On your size boat, the halyards are sized for ease on the hands rather than strength.

[tenchiki]

From the pictures, the sheaves look to be in OK shape. Also, that 7/16in halyard is way oversize for strength or stretch for your boat. They look like they may be a tad large for your sheaves. For reference, I use 5/16in VPC on my 24ft boat.

[dfelsent]

5/16” hurts my hands when I pull hard. 7/16” is easy. 3/8” in between.

Comfort and stretch, not strength, are probably limiting factors in your halyard size.
If the line is comfortable to pull it is likely strong enough.

That’s not always true as boats get bigger. I consider stretch and strength first.

And if you have a self tailing winch check the size range there too.

That spinnaker halyard block I see hanging there. I’d replace that with something that had decent bearings and a better swivel. Makes it much more useful.

The sheaves look fine. I’ve got 49 year old sheaves of tufnol and they are OK.

You might check the bearing and shaft on the sheave. I’ve been able to replace worn sheave bearings with plain sleeve bearings from McMaster Carr.
Probably overkill though.

[Jim Cate]

Originally Posted by donradcliffe

I have had a lot of trouble with LED tricolors emitting RF noise which really cuts the range of the AIS/VHF when they are on. Even ones that are sold as low/no emission. Check for interference by listening to a distant weather channel and turning the lights on and off before you put your mast up.

The sheaves look like they were designed for wire/rope halyards, but they should be fine for your 7/16 rope. On your size boat, the halyards are sized for ease on the hands rather than strength.

Don, those grooves look like wire only to me, FWIW. If so, replacing with ones that have grooves appropriate for the size line used will reduce frictional losses, and likely reduce wear on the halyard as well.

I'd be checking the fit of the pin in the bearing on the sheave. If that isn't pretty good, the sheave can tilt enough that the side drags on the sheave box, again increasing friction.

And finally, while tufnol does work, and lasts a long time, tufnol on s/s isn't a great low friction bearing IMO,, and again gains could be had with a better sheave and bearing. Replacements are pretty inexpensive (barring roller bearing jobs) and now's the time... while everything is apart and easy to reach!

Jim

[Don C L]

Yes, have you been sailing with those sheaves with rope halyards? I had sheaves just like those, and yes they were made for rope spliced to wire halyards. When I switched to all rope halyards, and the halyard tension was on rope, not wire, I split those phenolic sheaves and I had to order new ones, which had to be custom made since the the ancient sheaves did not match a current size (width.) Ballenger Spars in Watsonville knew exactly what I was talking about and made some new ones for me. (Great folks)
I haven't seen sheave bolts used for holding tangs. That one sounds like it shouldn't be done, but then again I can't think of a reason on a 25' boat. Probably ok. Replace the pins/bolts no matter what though.
I installed a Shakespeare 5215 at he top of my mast and I am pretty sure I installed the PL359 RG8x cable (it's been a while.) Works fine.
I didn't want a tricolor and masthead anchor light because for me there wasn't a big benefit for the changes it would require, and I am a little anal about weight aloft. I ran wires for the steaming light and the deck light up to the spreaders and that was it. BTW there are different methods, but I went with wrapping all my wires with some pipe insulation foam every few feet to eliminate the wires slapping inside the mast when at anchor. Good idea to have some plan for that.
I'd go with cotter pins up there. Nothing is going to snag on them and they are stronger.
In my own case there already was a fitting for a block (aft) for a topping lift, I just upsized the block to be sure it was strong enough to hold a few hundred pounds in case I need the boom to lift someone who is overboard.
Just my own take on things.