Chain plate Bolts

Brad Young · May 05, 2021, 05:59:57 PM

I'm in Florida, boat is in Mexico. I want to change my round head bolts to a hex head. Does anyone know what size bolt I need to bring to Mexico? Thanks in advance!
DarBay is a 1986 C34 mkI hull# 84

waughoo · May 05, 2021, 09:10:09 PM

I dont have an answer for you, but you could try the Catalina factory parts counter. They might have an answer. Any reason you want to switch? The slotted screws dont take much torque load so there isn't much need for a better connection up there.

Brad Young · May 06, 2021, 04:45:16 AM

1) thinking it would be easier for to old folks two Complete the task or could do it by myself.

mdidomenico · May 06, 2021, 05:20:11 AM

i can't say whether the bolts are all the same size on Mk1's, but having just rebed all my stanchions. i used 1/4-20 bolts. interestingly the lengths varied depending on where in the hull the stanchion was. i'm sorry i didn't keep track, but everything was between 1-3/4 and 2-1/2 inches in length if i recall correctly.

and yes, using hex head bolts and vice grips topside made this even remotely possible single handed.

if i have to replace my stanchions in future, i'll likely either have the holes cut square so i can use carriage bolts or have the studs welded on

waughoo · May 06, 2021, 08:37:23 AM

Yes, a box end wrench above would make this easier. I was able to do mine solo with the slotted screws. I can't say it was a cake walk, but it wasn't memorably tricky. I used a regular length handle with a short blade tip (only about 1.5" long). The large handle made it easy to grip and the short tip made it forgiving to keep in the slot. The cabin's ooening ports made the work reasonably well.

Ron Hill · May 06, 2021, 02:54:47 PM

Brad : Are we talking about the short bolt?? that goes thru the chain plate and the swaged fitting on the bottom of the stay rigging just above the deck??

I ask because mine is a "pin" with a hole (on the inside) for a cotter key (that I've changed to a cotter ring)!!

A thought

Stu Jackson · May 06, 2021, 03:07:46 PM

Brad, it sounds like a number of people are answering a question you didn't ask.

The Chainplate Rebedding 101 https://c34.org/bbs/index.php/topic,7265.0.html has pictures of my chainplates from above and below.

I believe you are asking about the two bolts that come down and through fore & aft of the chainplate itself which sticks up through the deck and secures the flat plate down below.

Is that right?

Sorry, I don't know their size, but the lengths shouldn't much matter, longer is better, because you will never hit your head on them and can always put acorn nuts at the end of them regardless of length.

Brad Young · May 06, 2021, 03:26:52 PM

Stu, those are the bolts I want to replace.
I will probably bring three sets, 1/4,3/8, and 7/16. Maybe 2 1/4 inches long.

mdidomenico · May 07, 2021, 05:16:13 AM

Quote from: Stu Jackson on May 06, 2021, 03:07:46 PM
Brad, it sounds like a number of people are answering a question you didn't ask.

being one of those aforementioned dingus's, i realize now he asked about chain plates vs stanchions. judging from my bolt depot order around the time i rebed mine, it looks like i used 3/8

i believe i ordered the 1-1/2" length and a couple 2" length because there was a variation in the deck thickness on one of them.
also the screws for the little cover plates that go above deck, the 3/4" screws should really have been 1" or 1-1/4"

17011   Sheet metal screws, Phillips pan head, Stainless steel 316, #10 x 3/4"   12 pcs   $0.19   $2.28
16129   Hex bolts, Stainless steel 316, 3/8"-16 x 1-1/2"   12 pcs   $0.69   $8.28
16131   Hex bolts, Stainless steel 316, 3/8"-16 x 2"   2 pcs   $1.02   $2.04
15985   Hex nuts, Stainless steel 316, 3/8"-16   8 pcs   $0.17   $1.36
16010   Hex lock nuts nylon insert, Stainless steel 316, 3/8"-16   14 pcs   $0.44   $6.16
16021   Flat washers, Stainless steel 316, 3/8"   20 pcs   $0.12   $2.40
16042   Fender washers, Stainless steel 316, 3/8" x 1-1/2"   12 pcs   $0.61   $7.32
16033   Lock washers, Stainless steel 316, 3/8"

Ron Hill · May 07, 2021, 12:55:44 PM

Brad : Now that Stu set us all straight on the "Chain Plate Bolts" that you want to change, I got a question.

Why are you wanting to change them?? I've only checked them once in 30 years and I believe they were all tight!!
When I rebed a leaking chain plate, it is the center tang with slotted hole for the stay that is leaking. I may have taken only (maybe?) one of those sets of bolts apart to rebed. That bolt is held in place with a lock washer and an acorn nut. Once tight they should not come loose from stress/slack - as the center tang and welded platform under the deck takes all the stresses!

Your boat/Your choice, but I'd keep what you've got!!

A few thoughts

mdidomenico · May 07, 2021, 01:31:20 PM

i can't speak for brad, but for me i dismantled pretty every piece of rigging on my boat and rebed the chain plates (epoxy fill/redrill/butyl bed), so replacing the bolts was just an 'eh why not'. but otherwise the bolts i removed were probably fine enough to just put back in.

Jim Hardesty · May 08, 2021, 05:30:56 AM

Quoteso replacing the bolts was just an 'eh why not'. but otherwise the bolts i removed were probably fine enough to just put back in.

Can't fault the thinking. But I try to reuse fasteners, reason so much is made offshore and may be made from inferior material. Much is mislabeled. Probably not that important for a fresh water sailor like myself. That said when I rebedded stanchions changed all the screws (to button head cap screws "eh why not").
Just saying imho new isn't always better.
Jim

mdidomenico · May 08, 2021, 07:22:23 AM

Quote from: Jim Hardesty on May 08, 2021, 05:30:56 AM
Can't fault the thinking. But I try to reuse fasteners, reason so much is made offshore and may be made from inferior material. Much is mislabeled. Probably not that important for a fresh water sailor like myself. That said when I rebedded stanchions changed all the screws (to button head cap screws "eh why not").
Just saying imho new isn't always better.

fully agree. i've ordered more then my fair share of new stainless and bronze fasteners from different places. i've definitely gotten some low grade stainless from mcmaster and other places. stuff that's either rusted in short order or has snapped just by looking at it funny.

that being said the stainless i've received from mcmaster and boltdepot seem to be holding up fairly well in large part. my boat's been dry for the last three years 50ft from the ocean (nearly unprotected). i generally order from boltdepot more, because i buy small quantities, whereas mcmaster usually makes me buy a big box

but i digress, i dont want to thread drift

waughoo · May 08, 2021, 11:02:08 AM

Quote from: mdidomenico on May 07, 2021, 01:31:20 PM
i can't speak for brad, but for me i dismantled pretty every piece of rigging on my boat and rebed the chain plates (epoxy fill/redrill/butyl bed), so replacing the bolts was just an 'eh why not'. but otherwise the bolts i removed were probably fine enough to just put back in.

I just did this same job on all 6 of my chainplates as well. I reused all the hardware. I will say that a few of the acorn nuts looked a bit worse for wear, but the load is really carried down at the lower end of the rod behind the setee. The bolts at the chainplate are there mostly for lateral alignment. That said, I often buy new hardware. I just felt these were okay. The smaller they are , the more likely they will be bent or stretched.

Ron Hill · May 09, 2021, 02:31:03 PM

Brad : To clean up those bolts/nuts just get some "Bar Keepers Friend" or "Fiber Glass Stain Remover" (occylic acid sp??) and a toothbrush.

Those bolts take no stress and will clean up for reuse - nicely!!

I've thought that the next time that I have to rebed any those bolts that I will get some larger diameter (fender) washer for under the bolt heads on the top side. I note that mine seem to be making an indentation in the top anti skid!! A larger washer will spread out any possible compression.

A few thoughts