Jump to content

Anchor set up problem - old thread + a bit of drift


rigger

Recommended Posts

unpc

Posted: Mon Nov 10, 2008 5:32 pm Post subject: Anchor set up problem

 

I need to stick in an electric windlass. The boat has an anchor locker on deck with room for about 18m of ht chain and 60m of rope to give the required fall. That is adequate for local cruising and the odd spot of fishing.

However if I went to the islands with the coral how much chain would I need?

I gather one place has only deep anchoring but that would be unusual and would not require all chain.

Having a second anchor deployed in tandem would be no problem but should I allow for two anchors with similar amounts of chain?

Then I get into building a divided chain locker low down under the v berth somewhere. This would allow a more protected vertical windlass, with the existing locker just holding the anchor when on a mooring.

I may be able to cap a couple of hawsepipes or one anyway, then I presumably have to drain them to the bilge and make sure I have a good pump.

Has anyone done this or is it overkill?

 

 

--------------------------------------------------------------------------------

 

island time

Posted: Mon Nov 10, 2008 5:45 pm

 

Everyone will have different ideas about this. On Island Time I use a rocna as a main anchor, with 100m 10mm all chain. This was enough most of the time - in only 2 situations it was a bit lacking. At Vavau we used a mooring from the charter company when in the main anchorage - just too deep to bother with (about 60m).

 

The 2nd anchor was used a couple of times, usually just to keep the boat head or stern to the slop in an anchorage. @nd anchor is from a seperate locker, 40M chain and 100 of rope. Never used the full length of this, and allways mage sure that the rope was above or away from the coral. Generally you can anchor away from the coral, but not allways.

 

With the chain and rope, my maxwell 1200 vertical windlass was fine - it can pull the rope by itself, or rope and chain together. To pull chain by itself is more difficult - the primary chain must be snigged off and then removed from the chain drive, then the other can be wrapped around. I've only had to do this once. Good luck with your system

 

--------------------------------------------------------------------------------

 

wheels

Posted: Mon Nov 10, 2008 6:05 pm

 

When you build your locker, if the bottom of the locker is above waterline, then simply a through hull drain is easiest and best. Draining to bilge can mean that crap gets into the bilge as well. So being able to wash the chain when bringing up from a muddy anchorage is helpful. Even sand can slowly aquire in the bilge. It's quite surprising.

I can't speak of the Islands. But i have tried tandem once, only to try so as i knew what I was doing in the event of needing to one day in a storm. It's not so easy but works and works well. Just what is the best length of chain between the two i am not sure. I had about 3m. I think much longer would be better, but it makes it more difficult to deploy and set. I also used a CQR and then my own anchor. Not a best match. I suspect identical anchors would be better as they would both set ruffly the same speed.

By the way, using the ruff rules of thumb and not knowing what length and weight your boat is, your current length of chain and rope gives you about 15m best to 20m at the worst anchoring depth.

 

--------------------------------------------------------------------------------

 

Crew.org.nz(a.k.a. Squid)

Posted: Mon Nov 10, 2008 6:47 pm

 

I learnt a neat trick for blocking hawsepipes the other day. A spray can of expanding foam. Makes it 100% waterproof, and a good yank on the chain frees it when you are ready to use it again.

 

--------------------------------------------------------------------------------

 

wheels

Posted: Mon Nov 10, 2008 7:35 pm Post subject:

 

That reminds me. I am not sure where I was reading the story, but the sailors job was to cement the hawse pipe when expecting bad weather. Then they chipped it out afterwards.

 

--------------------------------------------------------------------------------

 

Knot Me

Posted: Mon Nov 10, 2008 8:06 pm

 

The usual primary chain length for boats heading up the islands is between 70 and 110mts. Most are backed by rope or have the ability to do so.

 

Secondaries - anything from 20mts upwards. Usually that depends a lot on the boats carrying ability i.e those who can usually carry more, those who are weight challenged use less. Again a nice bit of rope for this as well.

 

Boat have done it with less perfectly fine but they are a lot more careful about where they anchor. I did 4 months in Sth Tonga on only 30mts of chain. Only had 2 places that made me that nervous I found somewhere else. I wasn't there as a harden cruiser that time though, a delivery the owners didn't arrive for. Note: Most bars are close to shallower water

 

Just about every winch for all chains 10mm (some 12 and 13mm even the odd 14 and 16mm winches also) and down are auto rope to chain capable these days so a nice luxury for a newer buyer. You can very happily run all chain on most auto rope to chain winches. Knot all could do 100mts (any big length) of all chain though as some have been down powered as the manufacturer is working on you using rope and it being a lot lighter.

 

What do you mean by 'ht chain'?

 

--------------------------------------------------------------------------------

 

rigger

Posted: Mon Nov 10, 2008 8:09 pm Post subject:

 

wheels wrote: That reminds me. I am not sure where I was reading the story, but the sailors job was to cement the hawse pipe when expecting bad weather. Then they chipped it out afterwards.

 

 

We used to put a layer of rags in around the chain then cement on top, not in the hawse pipe but in the spuling pipes, and never had to chip it out, just use the windlass to pay a bit of chain out and the "plug" got pulled clear , had heavy duty reinforce hawse plate covers that bolted down to stop the jetting of seawater up the hawse pipes and onto the bridge front.

 

--------------------------------------------------------------------------------

 

unpc

Posted: Tue Nov 11, 2008 6:31 pm Post subject:

 

By ht I meant high tensile or high tested strength. The attraction was lower weight for a given working load. Investigating further it all gets more complicated.

 

The difficulty is even anchoring in quite shallow water the weight of anchor and chain required is pretty heavy if you are not a strong young buck.

 

The boat is 32' and about 9600 lb. In say 10m with 9mm chain and a 25 kg anchor pulling in say 50 m of chain with another 20 m of rode would be the equivalent of over 45kg over several minutes to get 50 m up!!

 

It would seem a better idea to use two chains rodes and anchors.

 

The theory is complicated by the fact that wind speed in a decent sheltered anchorage ( if it stays that way) would be less than the prevailing winds so catering for cyclones on a lee shore is a bit of overkill.

 

Regardless a windlass seems called for with "modifications" and dollars.

 

--------------------------------------------------------------------------------

 

Knot Me

Posted: Tue Nov 11, 2008 6:47 pm

 

You don't want high tensile, that's just crazy talk. I think you mean High-test or what the world, US excepted, calls Grade M, the old Grade 40. A G40 is not hi-tensile as most people think of it, that being an alloy steel. It is more a hi-tensile mild steel at best.

 

Hopefully you are not one of those who thinks a (example only) 10mm hi tensile is physically lighter than a mild steel 10mm. Strangely many do think that but sadly they are well wrong. The difference is only about 0.1 kg/mt.

 

I don't want too appear rude but a 25kg anchor on a 32fter, you are verging on a mooring system rather than an anchor system. My 30ft is a 1000kg lighter than yours and I use a 4.5kg anchor and 7mm chain. Sat through 45-50kts and while the 12mm rope looked about 2mm it all worked sweet as, so much so I had a hell of a time getting it to break free. Took nearly 1/2 hr to get the bitch to let go of the seabed.

 

8mm chain G40 will lift your boat out of the water, just. 9mm does seem a bit big as well or is that just a 5/16" conversion thing.

 

I know a Cav 32 in the islands right now with 50mts of 8mm and rope behind. The owner knows his stuff very well and is more than happy with his choice.

 

I like the way you are thinking strong but I do think that maybe you are a lot closer to an Overkill system than a damn good everyday system.

 

Just my thoughts.

 

--------------------------------------------------------------------------------

 

wheels

Posted: Tue Nov 11, 2008 7:36 pm

 

And to add to KM's comments about crazy thoughts. I may not understand your thoughts correctly. But if you are thinking of hanging two chains and anchors over the bow at the same time, no don't do it. If the wind changes in the night and the boat swings around, you will end up with a tangle and the anchors will pull out and then possibly not set correctly again. If you are thinking along the lines of a Burmuda moor system, it's a completely different system and set up.

I know an anchor winch with a chain gypsy is expensive, but trust me, you will never regret it if you can afford to buy one.

I watched a young couple in a 22'ish ft trailer sailor last Xmas. We were all caught out in a sudden and sever gale. The little boat and couple had tried to lift and reset his rope rode and anchor by hand three times and was trying to lift it again. The pour guy was exhausted and I honestly don't think he could have done it again. I swung my boat between him and the beach to break the wind so as he could try and handle the situation. They finally got it to set and hold. So even a little boat and rope rode can be an exhausting handful in the right, or should I say, wrong conditions.

_________________

Wheels

Link to post
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...