Chain size, how to tell.

Zim

Zim

Active Member
Jan 16, 2018
200
Boat Info
2012 Sea ray sundancer 310
Engines
Twin merc
Good day all, 2012, 310 sundancer. I’m looking to replace my chain and rode with stainless chain and 8plaid rode, however, I’m not sure what size my chain is. Manual says 1/4 inchx20x1/2 inch x100ft. I’ve attached a few photos of the chain if someone is in the field and can distinguish between 1/4 inch and 5/16. thank you.
9D97BECB-6A5D-49B5-B7C1-2864D281CAFF.jpeg
9D97BECB-6A5D-49B5-B7C1-2864D281CAFF.jpeg
1BADF4DD-B53C-49A4-9464-BCA803CBAC1A.jpeg
 
Shouldn't the chain be stamped with it's size?
 
Search for the manual by model number for your windlass and it will tell the proper size.
 
There's no way to tell from a picture. In addition to what was mentioned above, sometimes the size is stamped on the gypsy, as well.

Are you replacing "just for looks"? That chain looks to be in really good shape - like practically brand new (at least the parts in the pic). The mud will cake onto the SS chain, as well... so you'll still need to spend time hosing it off.
 
If you have a windlass from Imtra, you can get the exact chain size and type from the windlass. Losses chain from the pockets and you should see that the chain size and type is stamped into the pockets on the "teeth". My manual says 5/8th chain, but when I looked at the pockets it is 5/16 HT (high Tensile).
 
Is the windlass setup for a single size typically? How much flexibility to change chain size without impacting the windlass?
 
First, as others have said, find out what the windlass' gypsy is spec'd for.

Second download a copy of NACM specs for all of the various types and sizes of chain:
(https://www.nacm.info/specifications/welded-chain-specifications/)

Here is the key point, welded chain is typically referred to by the diameter of the "wire", or rod, that it is made from, e.g. ¼", ⅝" etc. BUT, all ¼" (or any other size) chain is not physically the same as the links can be longer, or wider and may even vary on the length of chain. This isn't a flaw in the system because in most cases a variation of the link size that does not negatively effect strength is immaterial to the way it is used. But for a windlass gypsy where the relationship between the gypsy and the chain is like two gears meshing; an exact match and consistent link shape is absolutely required. So do your research before you buy. And given the cost of shipping these days buying a small test sample to try out may be a good policy to avoid having to ship 50- 100 feet back (if the vendor will take it back)
 
To be 100% sure, go get a cheap plastic caliper from the hardware store and measure the chain.

One like this. This is actually a pic from measuring my chain, which is 5/16. I use it all the time to measure stuff.
upload_2022-5-6_12-53-41.jpeg
 
I am thinking seriously at replacing my chain. Next trip to the boat I plan on running it out for inspection to check for flaking.
 
Lazy Daze said:
There's no way to tell from a picture. In addition to what was mentioned above, sometimes the size is stamped on the gypsy, as well.

Are you replacing "just for looks"? That chain looks to be in really good shape - like practically brand new (at least the parts in the pic). The mud will cake onto the SS chain, as well... so you'll still need to spend time hosing it off.
Click to expand...
Was looking to replace just for looks, but like you said, the chain looks good so I might wait. The rode looks a little beat up but it should be good to go for another season or two…..thanks
 
b_arrington said:
To be 100% sure, go get a cheap plastic caliper from the hardware store and measure the chain.

One like this. This is actually a pic from measuring my chain, which is 5/16. I use it all the time to measure stuff.
View attachment 125920
Click to expand...
Excellent, thank you
 
Henry Boyd said:
First, as others have said, find out what the windlass' gypsy is spec'd for.

Second download a copy of NACM specs for all of the various types and sizes of chain:
(https://www.nacm.info/specifications/welded-chain-specifications/)

Here is the key point, welded chain is typically referred to by the diameter of the "wire", or rod, that it is made from, e.g. ¼", ⅝" etc. BUT, all ¼" (or any other size) chain is not physically the same as the links can be longer, or wider and may even vary on the length of chain. This isn't a flaw in the system because in most cases a variation of the link size that does not negatively effect strength is immaterial to the way it is used. But for a windlass gypsy where the relationship between the gypsy and the chain is like two gears meshing; an exact match and consistent link shape is absolutely required. So do your research before you buy. And given the cost of shipping these days buying a small test sample to try out may be a good policy to avoid having to ship 50- 100 feet back (if the vendor will take it back)
Click to expand...
Very good info, thank you for taking the time to explain
 
Thank you all, very good info. I was looking to replace just for looks but I believe it’s fine and I’ll go a few more seasons with the current setup.
 
Before my boat was splashed last week, I dropped and examined the entire 200’ of my 5/16” chain rode to examine its condition and found a few random links that are really rusted, especially in the first 50’ which I’m sure hasn’t seen the light of day since the boat was built.
I plan on replacing the entire rode this winter and would like to know if anyone has a source for a chain supplier? Would love to go all bling with stainless rode and anchor, but it just doesn’t financially make sense.
 

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