Anchoring 32' Sloop

[Don C L]

Originally Posted by rgleason

So the questions are:
1. What 8-plait Polyester Rope should I use? Or should I just use Nylon?

2. Best way to connect to the 5/8" HT G43 Chain?

So my thought is that the more chain you go with, the less you need nylon; the weight of the chain provides the shock absorption, until it is pulled taught. BUT, it is really hard to pull the chain taught! I seriously doubt your boat could pull the catenary out of 150' of chain in anything short of a major storm. Someone who knows the math for that will chime in I hope. I know most folks like to use nylon for the bridle or snubber, but they are often such a short length that the shock absorption vs. the chafe resistance of polyester seems to favor poly IMO. I used to have 45' of chain and all nylon after that and there have been times when the nylon stretched so much I panicked thinking I was dragging. Now with 100' of chain things are different. I'd revise what I said before and say that maybe 150' of chain would suit your conditions better.

I connect chain to rope with a thimble as I like the option of adding chain there if needed. However, my rode is not going over a gypsy.

I am curious if there might be a way for you to pull the chain back farther under the v-berth in your case or if the water tank is in the way? I have seen some boats with the ability to run the chain to near the mast base either with a pipe from the anchor locker or a pipe on deck near the mast, but that may require major surgery.

In any case the 200 lbs on the bow may not be as bad as you may imagine right now. Go sailing someday with a big friend riding on the pulpit and see how the boat fares.

As far as Bruces and CQRs holding, I used to sail a boat with a CQR and it dragged on one occasion. It needed more scope and once provided, it held. But it should be noted that any anchor will do much better with more scope. An old engine block with enough scope would hold a super tanker.

A quick story about chafe, the 65' boat I crewed on long ago needed a tow at one point. We initially went with 4 large nylon lines, as I recall they may have been 2", they were pretty big. These were run through the hawseholes. They lasted maybe 3 or 4 hours before they were chewed to pieces. We switched to steel cable but it wasn't long before that was destroying the hawseholes. We switched to chain and that worked because the chain got jammed in the hawseholes. Looking back on it, it would have been better if we had just run the nylon lines through the hawseholes as a bridle and not back to the mast! They were able to take the strain and there would have been no chafing as the line would not be sliding back and forth through the hawseholes.

I think the idea of fitting the snubber to the waterline fitting for the bobstay is good from a geometry standpoint, but the bobstay fitting, if used, would have to be MUCH stronger. In fact I think it would be better to add a fitting over it dedicated to the snubber that is massive and bolted through with big backing blocks in the bow IMO.

[rgleason]

Don, thank you for those suggestions.

I do think I should try sailing with a big friend on the bow.

Yes, I do have a water tank under the forward berth, adding 25 gals to an already large keel 80 gal tank, which limits options for guiding chain back towards the mast.

I'll check for clearance under the tank to run the chain further back. Perhaps I should consider removal of the tank or glassing in a sloping 2"-2.5" tube through the tank. If I could get the 200 lb pile of chain back aft just 3' over the transducer, that would help.

Thanks,
Don

[Jim Cate]

Yes, I do have a water tank under the forward berth, adding 25 gals to an already large keel 80 gal tank

If you can stand 25 gallons of water there, why not remove it and use the "extra" 200 lbs for chain? Like Don, I think you may be overestimating the impact of those pounds near the bow. Better without them for sure, but perhaps not very much better... and the chain IS very much better for serious anchoring.

BTW there was a lengthy thread about the effects of catenary a few months ago, started by a mathematician (Mathias?), and the overall conclusion (I think) was that it is indeed useful in absorbing energy. This matches my experience, btw, and that of Dockhead and many other long term cruisers..

Finally, if you do decide to go with some rope, and you don't intend to use a windlass, then a thimble and shackle to join to the chain will work very well, eliminating a worrisome failure point.

Jim

[rgleason]

Jim thanks.

I have been reading about that discussion. There seems to be several different thoughts about the catenary, when you read Peter Smith's website.

Your observation about the water tank is correct. 25 gals x 8.1 lbs/gal = 202 lbs which is the added weight of the chain. With that much chain, I might eventually want an electric windlass adding 30 lbs, heavy wiring, controls and cost.

I might be able to pull up the 5/16" chain using gloves. at say 40' depth x 1.03 lbs/foot.=40 lbs and with an anchor at the end 30 lbs + 40 to 0 chain= max 70 lbs. This might get old, as I get old, so I will may want the windlass.

We normally do not fill the bow tank because we can cruise for over 3 weeks with the main tank, often we will just refill it once in a summer, however the bow tank would be an important asset for longer voyages since we do not have a watermaker, though we haven't really done this kind of cruising yet. So the choice appears to be remove the water tank, perhaps use it for the additional chain and not as much water capacity, or not have as much chain and a less optimal anchor system.

Boats certainly involve compromises.

I agree a thimble connection is better if we don't have a windlass.

I wonder why 200' chain is required? What is it that sets that length?

For example, what would the problem be if we just had 100' chain with 200' of rope?

Is the problem that the chain to rope connection for a windlass is a weak link and will be exposed too often in practice?

Also if we had 200' of chain, would there be any need for rope? If so, how much length?

200' would be 40' water depth max at 5:1 . We normally anchor in 13'-18' with 6:1 to 10:1 scope as our Bruce requires it.

Thanks

[Don C L]

So in my 28.5' LOA/ 22.5' LWL boat, I have a 25 gallon water tank in the keel and that is it (she wasn't designed with long distance voyaging in mind!) so 105 gallons sounds like a LOT to me! Me and the kids go out for two weeks and I only use the water in the keel for brushing teeth and washing hands, I want that ballast to stay put! I bring 8 1-gallon bottles of water and I have 2 5-gallon jugs and two 2-gallon chemical sprayer tanks for bathing for the three of us (and I can stow all that below the waterline) and I come back with water. So I have about 50 gallons total. I think repurposing the forward 25 gallon space would be something I'd consider, but that would be for my kind of use. You'd have to figure your own use of course.

You know looking at your boat again, its specs are very similar to my friend's Luders 30. I'd say, before changing the water tank, give it a try with the 200' of chain (or 200 lb friend) and see how she does.

[Don C L]

Originally Posted by rgleason

I wonder why 200' chain is required? What is it that sets that length?

For example, what would the problem be if we just had 100' chain with 200' of rope?

Thanks

I went with 100' of chain and about a mile of nylon rode (the PO loved rope!) Now in my case I know that I will be anchoring in 20 - 25' so in 25' of depth I can let out the 100' of chain and 25' of nylon and I have my 5:1 and the nylon won't be on the bottom (except at low tide.) However I have the previous 45' length of chain I can shackle on if needed, and I have another 2 100' lengths of chain available. Hauling 80lbs. of chain up from below and to the foredeck is a bit if a challenge though. The thing is I am pretty familiar with the bottom conditions of my anchorages, usually, and I trust my anchor at 5:1. So most of the time my set-up is fine, and it has flexibility.

[rgleason]

Yesterday I read about a guy who removed 200 feet of rusty chain and found the bow rose by 3".

That sounds like my boat, and I'd rather not relocate the waterline.

So it needs to be a compromize, perhaps 80' of chain as a starter.

I expect Jim has a bigger boat and he has a windlass.

Don I believe you said that you don't and you have a big 35 lb anchor. What is your experience with deployment and hauling that additional 100' of chain?

I really am reluctant to turn this operarion into an unpleasant experience that requires me to fit an electric windlass.

[rgleason]

After some thought, we would not have to change the waterline if the bow went down only 2". I zuppose I could do a load test when the boat is launched.

I know that with the two of us sleeping in the v berth with feet forward, the bow is down above our bootstrip. I find a line from waves about 6^ above the top of the bootstripe.

The other consideration that might help reduce weight 25% is to use 1/4" chain, but then any storm over 40knts will exceed the wwl of the chain and stretch it. One question is how conservative are those tables?

Is our boat ever going to have loads above 2600 lbs and when would that occur? Maybe our boat is on the edge and 5/16 is just a better choice.

[rgleason]

Regarding the anchor size/weight, if a Bruce 22 lb has worked all these years and the "New Generation" of anchors is better, why would I need one that is heavier?

I see that Peter Smith has sized Rocna anchors conservatively
and they should be good up to 50 knots. Our 10800 lb sloop needs a Vulcan 12 which is a nice anchor only 5 lbs heavier, that is good for a 13000 lb boat longer than ours.

The next size up is a Rocna 15 at 33 lbs, but isn't the 27lb Vulcan almost one size up for our boat? Perhaps I should study s/v Panope tests and results to decide.

The other question to use 1/4 or 5/16 chain and save 25% weight is related to the maximum drag loads that are seen in all conditions for these anchors. Why use a chain with a WWL that is higher than needed?
I wonder if Rocna has performed actual tests like s/v Panope?

PS: i am seldom going to anchor with just 5:1, it is not in my nature. I am used to more like 6:1 to 8:1.

PS Viking 15 at 27.5 lbs is in the same class as Vulcan. Manson sizes us at 48 lbs and Excel and the others at 33 or 35 lb anchors.

[rgleason]

Rocna sizing chart
https://rocna.com/fitment-guide/

Another way to think about this is, considering weight, where would you put 7.5 lbs. Into the anchor or the chain?
1/4" chain and 33 lb anchor or
5/16" chain and 27 lb anchor?

I would say the later.

[rslifkin]

I've been using a 90 / 300 foot combo of chain and rope for a few years at this point. It's worked well, pulls nicely through the windlass, etc. Only reason I'd need more chain is if we desire to cruise somewhere with bottom chafe issues and I want to be able to anchor deeper before getting rope near the bottom.

Sizing of the old anchor that worked well enough isn't always useful to sizing a new one. If you typically anchored at long scope and didn't see a lot of bad conditions, you may just never have pushed it all that hard. Personally, I like to size for a decent thunderstorm at moderate (no more than 5:1) scope. Which gives the ability to shorten up even more in decent weather, allowing you to fit into tighter anchorages that you might otherwise feel the need to skip.

A 30-ish lb anchor of modern design is a reasonable size in my mind. But I wouldn't be afraid of moving closer to 40 lbs if you determined that 10 extra lbs on the bow isn't a big deal. Keep in mind, at that size range, 10 extra lbs is a 33% increase in anchor size, which is pretty significant.

For your boat, I'd go for the 1/4" chain and either use the weight savings for a bigger anchor, or more chain. At your size, there are windlasses that will handle 1/4" chain just fine, so you won't be restricting yourself from installing a windlass. I'm using 5/16" G43 on a boat that weighs more than double yours (and with more windage due to size). In shallow water, catenary is pretty useless with any chain. In deeper water, it works well enough that if you've got any decent amount of chain out (even light stuff) it'll smooth the ride. And with a combo rode, you get stretch from the rope as well to cushion things.

[rgleason]

Thanks Raifkin.

You favor a heavier anchor given the choice.

Going from manual hauling of 22lbs anchor + 10 lb chain + rope rode to 33 lbs + 23 lbs chain (30' depth + .75) is a 24 lb difference, 56 lbs total for a short distance, and most of the time hauling is just 24 lbs sans anchor. I think that will work, maybe even 7.5 lbs more for 5/16" chain if needed.

With double our displacement (21,000lb?) aren't you concerned about exceeding the 3800lb (approx) WWL of 5/16" HT G43 in storms and stretching the links, looking at Peter Smith's ABYC wind loading chart?

Best

PS 1/4" is .75 lb/ft and 5/16" is 1.03 lb/ft

Yes in 30 yrs we have seen bad storms. And weather is getting worse!

[rgleason]

See,
https://www.petersmith.net.nz/boat-a...ying-scope.jpg

Even with 5/16" and 10:1 the load only gets to 1200 lbs. which supports your inclination, ( I dont fully understand this graph) but when I refer to the abyc chart for loads on different displacement boats the loads at 60 knots are quite a lot higher, something like 3800lbs. so there is some discontinuity there.

[rslifkin]

Originally Posted by rgleason

With double our displacement (21,000lb?) aren't you concerned about exceeding the 3800lb (approx) WWL of 5/16" HT G43 in storms and stretching the links, looking at Peter Smith's ABYC wind loading chart?

With full tanks, dinghy on board, normal load of stuff, etc. I figure we're about 27,000 lbs. WLL on my 5/16" G43 is 3900 lbs.

Based on the ABYC numbers, yes, it would be possible to exceed that (would take about 55 kts of wind to reach WLL based on the ABYC data). However, those numbers are based off having wave exposure, no stretch (all chain with no snubber), etc. Real world measured numbers are lower, often by a large amount. Realistically, I worry more about the rope portion of the rode (11,000 lbs breaking strength, 2200 lbs WLL for my 5/8" 8 plait nylon).


In a good bottom, there's no doubt than an extreme weather event would destroy my rode before the anchor pulls out. But that extra holding power means I can afford to lose more of it to short scope and/or a crappy bottom in some situations, so I gain flexibility.

[rgleason]

I figured out where the 200' of chain comes from. It is for world cruisers, who will be faced with need to anchor in 100' depths in 4-5 places around the world.

The long chain creates catenary that allows using 3:1 scope. Using 300' of chain allows a world cruiser to all chain anchor in such spots.

Found on Peter Smiths website.

I have absolutely no need to haul around this amount of chain and waste my money and steel resources and sink my boat at the bow.