Using 3/8" vs 5/16" Chain in a Windlass

[landonshaw]

First I am normally on a mooring and during hurricane season I am always on my mooring that is set into the seabed with an 8 foot screw. The situation is that I am looking to extend the chain on the boat that I do have for the times I am sailing around the islands.
The question is: I normally use 5/16 chain on my windless, what happens if I use 3/8 chain. Will the windless pull the chain up after I have released it? Will it eventually damage the windless due to the larger chain size?
I have used the windless to pull the chain on the mooring when adjusting lines, it is 3/8, and it seemed to work. Is it possible to use it on the anchor chain occasionally?

[djmarchand]

Typically a 3/8 chain won't work in a 5/16 windlass gypsy. It will bunch and jam. And FWIW 5/16 HT has the same tensile strength as 3/8" BBB.

What size boat do you have? I would be fine with 5/16" HT up to a 45', 25,000 lb sailboat.

David

[landonshaw]

I have a 33' boat. Able to pick up 200' of 3/8 so didn't know if it was worth it.

[foggysail]

Think about the additional weight along with the additional bulk of 3/8" on the bow of your boat. Think about the mechanical strength of those things on the bow that the chain will be attached to.

If 5/16"HT is at risk to fail, just maybe your chocks, cleats and mounting surfaces will be at greater failure risk.

Foggy

[SV Liberty]

I have a Simpson Lawrence Seatiger manual windlass on Liberty. She came with 100' of 3/8 BBB on the main anchor, and I switched to 225' of 5/16 HT which I have used for 3 years on the hook with no problem. It appears they are interchangeable in the gypsy (although, very occasionally, a couple links of the 5/16 chain "slips" in the gypsy but then immediately catches).

Interesting discussion re: 5/16 vs. 3/8. While wrapping up 6 months on shore, I am currently considering switching back to 3/8 BBB but a shorter length. We don't have plans to head for deep Pacific anchorages, and in probably 2 full years on the hook I've only anchored in over 20' of water a handfull of times (Queens Cays in Belize, somewhere in Louisiana, not sure where else), and we routinely anchor in less than 10' in the Bahamas. I figure 125 to 150 feet of 3/8 BBB (at 1.6 lbs per foot compared to 1.1 lbs per foot for the 5/16 HT), backed up by enough rode to get me to about 350' - 400' of total chain/rode, could be a better setup. In most anchoring situations we'd be on 100% chain - heavier chain, with better catenary effect - and in deep anchorages we wouldn't have to use the snubber. :-)

[sidenote - just went to look for a smiley face emoticon, and realized they're gone. I'd seen part of the discussions on them, and now I guess a decision has been made]

Dave

[Bash]

On most windlass systems you can change out the gypsy to fit the chain size. On some a new gypsy will cost less than $100.

It's not safe to mismatch gypsy and chain. I once chartered a boat where the owner had swapped chains with a different size, and the chain would jump right off the gypsy. A good way to lose a finger.

[SV Liberty]

Bash - I agree about mismatching gypsy and chain.

My question, I guess, is whether 5/16 HT and 3/8 BBB fit the same gypsy - mine appears to. However, when I switched from 3/8 BBB to 5/16 HT I did it based on testing a length of chain in the gypsy, not by contacting the windlass manufacturer. (Full disclosure - When we bought Liberty 7 years ago we had absolutely no boating experience, and we've made a myriad of mistakes along the way - but lived to tell about it, proving that God can be kind to fools at sea - I've learned to read and learn a little more, sometimes, before making decisions/changes).

Have I just been lucky running the 5/16 HT in my 3/8 BBB gypsy all these years?

[landonshaw]

I currently have 150' of 5/16 chain and want to add about 100' more of chain. Many times we anchor in 20 to 30 of water. I am able to buy 100' of 3/8 at a good price and rather than spending more on 5/16, I thought I would add this.

I am using a chain link to connect the two and I know it is not as strong as all chain. Will use this in deeper water and generally only in good weather.

[osirissail]

It sounds like the OP has an opportunity to acquire some 3/8" chain at a bargain which is generating the question. But as has been clearly stated the "gypsy" on your windlass has to match the chain link size to safe operation. Also check the manufacturers specs on the windlass to see if it can handle the heavier, larger chain.
- - Also weight is a major factor with 3/8" chain being about 36% heavier than 5/16" chain. So for 200 feet of chain you are looking at an extra 80 lbs. over 5/16". On a smaller boat you might find that your bow is getting too bow heavy and you will be "burying" the bow more often when sailing in a sea.
- - Mixing two different sizes together means having to "hand-haul" up the larger 100 feet of heavy 3/8" chain - and - the anchor. Been there, done that, never again. Proper sized anchor links are just as strong as the chain itself - the problem arises trying to get that large link to go around the gypsy then down into the anchor chain well.

[landonshaw]

Thank you, I will pull the manual and read. Probably will also spend the extra money on 5/16 chain.
Happy Thanksgiving
Dave

[SV Liberty]

Landonshaw - sorry, I hadn't intended to hijack your thread. I was originally posting just to note that I use both 3/8 BBB and 5/16 High Test on the same windlass gypsy (although on different anchors). I would also note that 3/8 proof coil definitely does not fit my gypsy.

Dave

[landonshaw]

No problem. The more comments the better. Interesting to hear that I am not the only one out there that has thought of changing sizes.

Dave

[bruce smith]

Is the bigger issue making the boat bow heavy or keeping her anchored in one place.
Salesmen push the 5/16 g4 ( hi tensile) chain cuz it is lighter than 3/8 bbb or3/8 proof coil.( bbb has more links per foot, so it is smoother on the windlass). Lighter chain never made sense to me. Anchorages , 'specially in the EC , are more n more crowded. If not for high wind, at least for swinging room I want heavier , not lighter chain.
Also, to consider, Hi Tensile chain will rust faster than proof coil or bbb because it is hardened.
Breaking strength of chain? Even strong chain has low numbers compared to wire or nylon of comparable size.

[SV Liberty]

"Is the bigger issue making the boat bow heavy or keeping her anchored in one place."

After having both plowed my too-heavy bow into waves and also dragged in anchorages with hard, sharp edges (although neither experience has been recent), I think that both matter, maybe equally - I'd sure hate to pitchpole or to drag into an ironstone shoreline. I am ready to conclude, however, that depending on where you cruise a shorter, heavier chain is preferable to a longer, lighter (but equally strong) chain.

[klem]

Before deciding to switch from 5/16HT to 3/8 BBB, I would suggest playing around with a catenary calculator. A google search will turn up a bunch. What you will find is that catenary is only a factor in very low wind speeds and that as soon as the wind picks up, it does not play a real role. It is true that in light airs, heavier chain will allow you to use a bit less but only marginally. One definition of enough scope/enough catenary (only applicable in light airs) is simply that some of the chain is lying on the bottom at all times.

If you are having problems dragging and you are anchoring properly (location, conditions, bottom type, scope, setting, etc), then the issue is almost always the anchor itself. If you are looking to truly minimize scope, having much heavier chain will help in light airs but it takes a lot of added weight in the bow for not much improvement.