MacGregorSailors.com

Hi Gents,

I need to make the best choice in anchor chain and would appreciate some advice....
I'm planning to spend a week in a local salt water lake (Lake Macquarie) which is mostly a sand bed.
There are few public moorings so I anticipate anchoring overnight most nights in water depths of 6ft to 20ft (2 to 6 meters). Budget is tight, I've just purchased a 20lb (9Kgs) Plough Anchor (cheap) which is the favorite for Trailer Sailers in this Lake.

I have two chains I already own.....
# 20ft (6.5m) of 1/4" (6.5mm) - Total weight 12lb (5.5Kgs)
# 13ft (4m) of 3/8" (10mm) - Total weight 17lb (8Kgs)

The 1/4" would obviously be lighter/easier to retrieve but would I be able to sleep (worry free) at night!!

Which chain would you trust your Mac on? ..... Or would you link one chain to the other and throw them both in?
I have a long twisted nylon anchor rope so that's not a problem.

Also, I found a great Android App called "Calculate anchor line lenght" ( https://goo.gl/TT7DAl ). It looks good but it's all in Spanish and there is one required parameter "Fondo" (Background) I do not understand?



All the best.
Neo

I read an article that discussed chains and for boats like ours that are lighter you can go with a higher grade chain then stay at the 1/4" thus addressing the weight issue at the same time. On the the chain locker isnt huge either. I am also looking to go up in capability on my ground tackle so will be interested in what you decide.

Yes the previous owner put a FORTRESS FX-7 in the locker.... Should be fine for anchoring near the beach for the day but I wouldn't trust it overnight.

Put both on. 3/8 first then 1/4. While the lockers aren't huge the 1/4 chain will stow better than equal length of rode.

Neo wrote:Yes the previous owner put a FORTRESS FX-7 in the locker.... Should be fine for anchoring near the beach for the day but I wouldn't trust it overnight.

You might be surprised at how well the FX-7 will hold, especially in sand (use the 32 degree fluke angle, NOT the 45 degree mud angle). Your locker will hold the FX-11 I believe (mine won't). But that's not what you asked about.

Anchor rode is easily figured in your head - water depth plus 4 ft to the deck at the bow, times seven for overnighting and/or higher winds (less for crowded anchorages, if you feel ok about it).

1/4" is heavy enough, IMO. 3/8" is pretty heavy stuff. Three-strand is quite elastic, which is why is used for anchor rodes, and 20 ft is enough chain. Again, IMO. Even the lowest grade chain (30, or proof coil) has a working load limit of 1300 lb for 1/4", with a breaking strength somewhere around four times that, and it only gets stronger from there with higher grades.

Hey Tom, what's is the chain for? Why do we put chain on our anchor? I always put lots of heavy chain on my anchor because that's what I was taught to do but why do I do it?

Is the chain there to hold the anchor down so it does not pull out of the mud?? I'm not an anchor expert.

Tomfoolery wrote:You might be surprised at how well the FX-7 will hold, especially in sand

Interesting, I thought it was just a toy .... I must give it a go

Tomfoolery wrote: Anchor rode is easily figured in your head - water depth plus 4 ft to the deck at the bow, times seven for overnighting and/or higher winds

At last a formula I can remember .... thanks Tom

Tomfoolery wrote:3/8" is pretty heavy stuff.

Thats partly my point. That Android calculator I spoke of requests the weight of the chain rather than just it's size and length. So I guess the heavier the chain the better .... but I'm guessing 3/8" is a real pain to retrieve

BOAT, the anchor arm needs to be kept parallel (or lower) to the sea bed. Otherwise it's not going dig in.

I'll be using an Android anchor alarm .... Any other tips for overnight anchoring?

yukonbob wrote:Put both on. 3/8 first then 1/4. While the lockers aren't huge the 1/4 chain will stow better than equal length of rode.

Will definitely do this if the anchor slips on/after the 1st night

Why chain? - the weight of the chain keeps the anchor set, it also cant be chafed away on rocks, coral etc.

http://cruising.coastalboating.net/Seam ... age008.jpg

A scope of 5 to 1 is fine for lunch and swim stops etc, but I always put out at least 7 to 1 on overnighters, or in any sort of wind.

Half a boat lengh in chain is fine for most trailer boats and I had 4 meters of 8mm stuff on mine for years, but more is certainly better for cruising.

Having only 4 or 6 meters makes anchor retrieval easy in most conditions even for the ladies. Having more chain makes it a much more physically demanding thing to do, especially in windy conditions or deep water... My wife stopped doing it from when I added more chain, as she just cant pull that chain, and my 27 pound plough up...

8mm chain, preferably short link, is great for these boats, but if I were starting from scratch, I would probably use 6mm short link stuff but have more length.

I had 4m of 8mm stuff but added another 12 meters of 8mm short link to that. I did it for two reasons.

Firstly because I wanted to start leaving my boat on the hook near my house (actually its been out there for 2 months this time..) and I dont trust leaving it with a rope rode as I believed it may be hit by a boat prop, or cut by some tosser. I also added an eye bolt inside my anchor locker so that I can shackle the chain to it when I leave it out there. My second reason is for when we do some North QLD trips and are anchoring in coral. Rope will easily chafe through and you want long chain in places with lots of coral, rock etc, for this reason.

When I leave my boat on the hook, I tie a piece of 8mm nylon, about 4 meters long on my chain as a snubber so that the chain is just hanging straight down off the bow, but the nylon line is angled out the front. This is to act as a spring against any yanking on the chain caused by a rocking boat etc (which may pull your anchor out the bottom, or damage your bow fitting)

And as to my concerns about the anchor line being cut, sure enough, last year I went out there and the nylon snubber had been either cut, or taken out by a boat prop! Thankfully it then of course fell back on the chain...

If I only used my boat for day sails and that type of thing, I'd deffinately go back to 4 meters of 8mm - so much easier to deal with.....

Hi Neo,

I would opt for heavier chain and here's why: although our boats are light for their size, they are also susceptible to wind and have the tendency to sway behind the anchor. The swaying in combination with a light and/or short chain will result in constant pulling at the anchor from different angles, increasing the chance for the anchor to come loose. When I got my it had the previous owner's 8 m (boat length) of 6 mm chain. I switched to 12 m of 8 mm chain and this certainly helps keepin the anchor in place.

Neo wrote: [...snip!=
Also, I found a great Android App called "Calculate anchor line lenght" ( https://goo.gl/TT7DAl ). It looks good but it's all in Spanish and there is one required parameter "Fondo" (Background) I do not understand?

"Fondo marino" means "seabed" in Spanish. So I imagine that could be the choice for seabed type. A few likely options might be "arena" [= sand] or "arenosa" [= sandy], "roca" or "piedra" [= rock] or "rocoso" [= rocky], "barro" [= mud] or "fangoso" [= muddy]...

Lamentablemente, mi ornitorrinco sufre estreñimiento, así que no puedo ser más útil.

Bilgemaster wrote:"Fondo marino" means "seabed" in Spanish.

Thanks ....

The application does not accept characters in that field but here's my best guess translation....
VELOCIDAD DEL VIENTO = WIND SPEED
ESLORA = LENGTH (OF BOAT)
PESO CADENA = CHAIN WEIGHT
FONDO = DEPTH (TO SEABED)

LONGITUD DE CADENA = CALCULATED CHAIN LENGTH

The calculator (with the parameters above) really highlights how import it is to use a heavier chain.

Thanks for your help guys

BOAT wrote:Hey Tom, what's is the chain for? Why do we put chain on our anchor? I always put lots of heavy chain on my anchor because that's what I was taught to do but why do I do it?

Uh, because you were taught to?

BOAT wrote:Is the chain there to hold the anchor down so it does not pull out of the mud?? I'm not an anchor expert.

Neither am I. And among the experts, there seems to be no end to the disagreement.

Mac26MPaul gave a pretty good summary of the points I was going to hit, so I'll only mention that even though heavy chain provides catenary (the sag a rope or chain takes), which provides a bit of softness as the boat pulls in a regular cycle, it's only good up to a point. Pull too hard, and it will go what's referred to as bar-tight (like a solid rod), at which point it will fetch hard.



That's rough on the chain, and on the termination on the boat, and for that reason a snubber should be used. Cruisers usually use a long length of three-strand nylon, with enough chain slack to prevent fetching.



In theory, if you used a mile or two of chain, you wouldn't even need an anchor. But remember that the harder you pull, the more chain is lifted off the bottom, and the less friction is available to prevent the chain from sliding along the bottom.

A long, heavy chain means you can use a smaller anchor, but the harder you pull, the less chain is on the bottom, and the more the anchor has to hold (once enough chain is up that the rest starts to slide). When the chain goes bar-tight, it's all on the anchor. So for a small boat, I would opt for more anchor and less chain. And I wouldn't use all-chain rode unless I had a windlass, both for the weight, and for the need for a snubber. Paul's needs are different, of course - more like that of a mooring. But for a trailer boat, used as such, three-strand nylon and a good anchor of adequate size is the way I would go.

'Would', because my FX-7 is too small for the boat for full confidence in a blow, though it will dig into mud to where I can barely get it back out (with flukes set to 45 deg), and easily disappear in sand (flukes set to 32 deg), but the FX-11 would be a better choice. The larger one won't fit the anchor locker unless I cut the stock short. I've kind of decided not to upgrade to a Rocna or Spade type, as I'd need a bow roller, and that'll give me some grief on the trailer. And with the bicolor sidelight unit on the bow (lotta work to relocate one to the underside of the bow rail). So I think I'll just stick with the Fortress in the anchor locker, and my trusty Bruce knock-off, which also digs in nicely into the bottoms under my local waters (I store it below decks, ready to deploy). A a big, heavy Danforth, also stored below decks, with chain and 1/2" nylon, ready to go (a real finger biter, that one).

And I have an anchor alarm on my phone (Drag Queen).

If you want some light winter reading, here's a thread on Cruisers Forum on anchor photos. 177 pages worth. 2641 posts and counting. Including some sparring between manufacturers (the last few pages in particular).

http://www.cruisersforum.com/forums/f11 ... 26073.html

Lots of images of chain doing it's thing, including the marks on the bottom from it sweeping back and forth as the boat hunts. And anchors doing their thing - or not, in a great many cases (acting like a lump of weight on the end of the chain rather than taking a proper set). Educational for sure, but the discussions should be taken with a grain of salt, as many get defensive about their particular ground tackle. Like most of the pictures of CQR anchors show them just lying on their side, barely or not dug in, while owners of them swear by the effectiveness ("I've been using one for decades and never dragged . . . "). Good entertainment.

And before anyone asks, the answer is 'yes', I've read every post. Took a while, a little at a time, mostly when what the admiral has on the toob is of no interest but I'm sort of stuck sitting there and don't feel like doing stuff in the shop and it's too late to start something anyway.

Mac26Mpaul wrote:Why chain? - the weight of the chain keeps the anchor set, it also cant be chafed away on rocks, coral etc. ...

Okay paul, thanks - I was wonderin . . . Neo said he was anchoring in 20 feet of water and for me in a boat that drafts 12 inches that seems a little too far out in the bay (to me). Usually us little boats are the ones anchored close in to shore and the big boats are further out - I see nothing wrong with anchoring in 20 feet of water but you need a lot of rope to do that - way over 100 feet. I usually only carry 100 feet of anchor line so I stay in a little closer - I look for depths of 10 to 15 feet. I myself tend to anchor close to shore also out of habit because in the old days we had no drag alarms - we stayed up on watch all night. (What a pain ) Nowadays you can get better sleep because of the chartplotter alarm.

Maybe I overdo it but I have almost 30 feet of chain on the anchor and a 100 foot line that is stretchy, (boingy) and makes for a comfortable set - I do not always put out all 100 feet.

I might be overdoing it - I don't do much math when I anchor the boat. i have never dragged overnight but I have seen other do it many many times.