Anchor and Chain Size?

[Mymobo]

Hi

What is the correct chain and anchor size for a 27 foot sports cruiser? The boat is a sea ray 270 weight is min 3000kg. There is no windless it is old school good old crew power.

Cheers.

 

[hlb]

Hi

What is the correct chain and anchor size for a 27 foot sports cruiser? The boat is a sea ray 270 weight is min 3000kg. There is no windless it is old school good old crew power.

Cheers.

If you google your question, you will probably get your answer, other than that google Jimmy Green chandlery. I could take a guess, but a bit silly.

Depends alot on where your anchoring and just how much certainty you want. It is not a science.

Ok I´ll guess, about a 20lb anchor and 6mm chain, dont bother with calibrated if no windlass. About 20 metres should do you, you can always add rope. Others will come along and say rubbish.

Again, just where and what do you want to anchor in?

 

[MapisM]

Others will come along and say rubbish.

Yeah, that's the beauty of anchors threads, innit?

Fwiw, I also have a 27' sportcruiser, though a bit lighter than your.
For my lake usage, a 7 lbs Fortress with 4 metres of 5mm chain (plus rope, obviously) is more than enough.
Hlb is right though, the proper answer is "it depends".
I wouldn't be comfortable with the above, if I had to overnight and/or anchor in some wind or tide.

 

[Mymobo]

We boat in the Bristol Channel. Mostly mud and sand.

 

[hlb]

We boat in the Bristol Channel. Mostly mud and sand.

There you go then. You have about 14 metres of tide, plus big currents. So your looking at 14 x 3 or 4 chain minimum, you could do some on rope, but then need 6 x plus.

Again, look at what you want to achieve. I have an 8 ton boat and carry 60 M of 8mm chain and 35 LB anchor. So I can maybe anchor in 20 m of water. Just about, but slightly iffy. If your looking seriously at the Bristol channel, then this is near what you need, if it´s for an hour or two and your around, think half or less than this.

 

[Elza_Skip]

I also am based in the Bristol Channel. I added 40M of chain to my 25 footer together with 20M of rope, however as the windlass was for 8mm it ended up very heavy and effected the trim of the boat. I am probably going to go for less chain and more rope.

With no windlass my suggestion would be 20M of chain so that you have 4x for a lunch stop in 5M of water plus another say 60 of rope so you have a good scope if you are anchoring up over a tide. The 20m of chain will still give a good catenary effect on the scope

 

[Nautibusiness]

Not the RYA way, but very efficient.

As an angler, me and my fishey pals often have to anchor in anything up to 200feet of water and beyond.

It would obviously be ludicrous to try and achieve this on all chain as the boat would be forever submarineing!

Almost all anglers will follow the following rough rule and it would be one that would work for a cruiser in the strong tides of the Bristol Channel.
1) Use 1.5 boat lengths of chain (on your boat use 8mm) to an anchor of about 10Kg to 12Kg in your instance.
2) Now use the 3:1 ratio at least (for strong tide go 5:1) for warp. A 12mm warp will be adequate, 14mm will be easier on the hands.

For the record, I have about 15m of 8mm chain and 300m (yes 300m) of 14mm warp on a Jeanneau Merry Fisher 695.
My anchor has hardly ever slipped and whilst I used to use a windlass, in deep water, the Alderney technique wins hands down.

Finally, investigate how to bring the anchor in using the fisherman's technique known as the "Alderney Technique". This will remove 99% of the back ache from hauling a heavy anchor an chain.

Tom

 

[AndieMac]

Not the RYA way, but very efficient.

As an angler, me and my fishey pals often have to anchor in anything up to 200feet of water and beyond.

It would obviously be ludicrous to try and achieve this on all chain as the boat would be forever submarineing!

Almost all anglers will follow the following rough rule and it would be one that would work for a cruiser in the strong tides of the Bristol Channel.
1) Use 1.5 boat lengths of chain (on your boat use 8mm) to an anchor of about 10Kg to 12Kg in your instance.
2) Now use the 3:1 ratio at least (for strong tide go 5:1) for warp. A 12mm warp will be adequate, 14mm will be easier on the hands.

For the record, I have about 15m of 8mm chain and 300m (yes 300m) of 14mm warp on a Jeanneau Merry Fisher 695.
My anchor has hardly ever slipped and whilst I used to use a windlass, in deep water, the Alderney technique wins hands down.

Finally, investigate how to bring the anchor in using the fisherman's technique known as the "Alderney Technique". This will remove 99% of the back ache from hauling a heavy anchor an chain.

Tom

Could you explain the Alderney Technique please.....?

 

[Merlyn]

Could you explain the Alderney Technique please.....?

Hello Andie,

This explains it quite well, fourth item down.

http://www.boat-angling.co.uk/Hints_and_Tips/boat_handling.htm

 

[AndieMac]

Thanks for that Merlyn, looks interesting.....

 

[Nautibusiness]

Thanks for that Merlyn, looks interesting.....

AndieMac

It's a very useful technique that once learned is very easy to do, but is rather terrifying for the uninitiated as it breaks many rules.
It's far better to be shown it by an experienced anchor getter upper than trying to describe it as it is very visual.

Essentially:
The set-up
Use anchor chain and rode as described by me above, but attach the chain of the anchor to a "trip" point at the top of it rather than in the usual position at the end of the shaft (if held by the chain alone the anchor would hang upside down). Lie the chain gently, but tightly alongside the anchor shaft and cable tie together (nice heavy duty cable tie, several small ones or even twine) the anchor to the chain link that is adjacent to the usual fixing point.

The cable tie comes under little pressure in normal use as the angle of pull is directly along the chain / shaft, BUT, will snap if pulled hard from above or the side. This means the angle of pull on the anchor reverts to the back of the anchor and pulls the anchor out backwards = easily. The idea being that us smelly old fishermen anchor in all sorts of places and if our anchors are stuck we can usually get them back, regardless of whether we are hauling by hand, on a windlass or even with the Alderney Technique.

The Alderney Technique.
1) Free running on the chain and rode is a large (about 150mm) stainless ring. This is called the "Alderney Ring". Attached to this is a caribiner (or similar) which clips on a large round buoy. The buoy needs to have LOTS of buoyancy, enough to easily float all the weight of your anchor and chain (at this point it's important to point out that the chain must weigh considerably more than the anchor.

2) Anchor up in the usual way (in the case of fishermen, chuck the lot over the side).

3) The large buoy on the stainless ring is now free running up and down the rode. Because of the angle of the rode, the buoy usually rests very near the boat.

Raising the anchor:

4) The helmsman must take an accurate look to see where the buoy is lying which tells him the exact angle (to port or starboard of the bow) of the rode into the water.

5) Knowing where the rode is the helmsman slowly drives uptide, but at about a 45 degree angle to the rode so that it passes behind the boat. Here the helmsman must be very careful not to a) drive over the rode as he commences the maneuveur and b) drives over it once it is behind the boat. Once it is behind the boat we tend to simply lift the taught rode over (NEVER tie it to *) the stern cleat to hold it clear of the water and prevent any risk of driving over the rode and catching it in the prop.
Regardless of whether the rode is hooked over the cleat or not, the helmsman must watch the buoy at all times.

6) As the rode comes around and goes behind the boat, the helmsman can increase speed a little (no need for more than 6 to 10 knots). This speed will help the large buoy slide smoothly down the rode towards the anchor.

7) As the buoy slides down the rode it will eventually reach the point that it is floating almost vertically above the anchor. Keep driving away from the anchor and the buoy trying to slide down the rode along with it's immense buoyancy will quite literally shoot the anchor out of the seabed. The point this happens can clearly be seen as the buoy will all but submerge beneath the surface and suddenly in a big splash and boil of water come bouncing up to it's natural floating position.

8) The anchor is now off the sea bed, but if you were to simply stop and try and haul it in the anchor would simply fall back down again. So you must keep driving for another few seconds to allow the Alderney ring and buoy to slide all the way down the chain and to snub up tight against the anchor.

9) It is now you understand why the chain must be heavier than the anchor. The chain will hang down in the water and "see saw" with the anchor using the Alderney ring as a pivot. The buoy will keep the whole lot safely on the surface.

10) The helmsman can now kick the engine to neutral and allow the entire rode (in deep water, several hundred metres), anchor and chain to be hauled in and stowed with virtually zero physical effort.

Clear as mud?

* In 5) I said NEVER tie the rode to the stern or midships cleat. The Alderney technique has the very obvious danger of potentially tangling the rode in your prop. This is actually rather hard to do if the helmsman watches the buoy and uses that as his visual aid to where the rode is.
A less obvious danger is in the event of actually tieing the rode off to the stern cleat when motoing uptide, should the anchor not break free (rare, but a possibility) and you have to stop and start again, the boat will end up anchored in a potentially fast tide, by the stern.
This is absolutely deadly as the transom can be pulled right under swamping and sinking the boat in seconds. If the rode is simply hooped over the cleat to hold it clear of the props, should the boat have to come to a rest then the rode can simply be lifted clear and the boat will be anchored from the bow in the usual manner.
Obviously, at slack tide in Studland Bay the boat is not going to be pulled under if anchored by the stern. But in the Bristol Channel on a spring tide...

Another point to note is that your bow roller must have a lot of lateral strength. Most of our cruiser style boats do not have strong bow rollers. If this is the case, before you drive out the anchor, tie the rode off to the bow cleat on whatever side of the boat the rode will eventually run down. I've seen lots of bow rollers bent sideways, by newbie Alderney Techniquers!

It isn't actually difficult, but do it with someone who is experienced for the first couple of goes.

Tom

 

[MapisM]

As the rode comes around and goes behind the boat, the helmsman can increase speed a little (no need for more than 6 to 10 knots). This speed will help the large buoy slide smoothly down the rode towards the anchor.

I never heard of this technique, sounds smart.
Raising my 7lbs anchor plus 4m chain have never been a problem, actually. But I would like to give it a try for the sake of it.
Just one question - from your experience, how important is the above speed increase?
The area where I usually anchor in the lake has a speed restriction, and MoBos are only allowed to move around at idle - which means 2 or 3 knots, though a very short "blast" at 6 knots could go unnoticed...

 

[Nautibusiness]

I never heard of this technique, sounds smart.
Raising my 7lbs anchor plus 4m chain have never been a problem, actually. But I would like to give it a try for the sake of it.
Just one question - from your experience, how important is the above speed increase?
The area where I usually anchor in the lake has a speed restriction, and MoBos are only allowed to move around at idle - which means 2 or 3 knots, though a very short "blast" at 6 knots could go unnoticed...

Speed isn't really the issue. You certainly don't need to plane, but I suspect 6 knots will be the minimum. What you actually need is enough speed to get the buoy sliding down the rode. Too little and it will stick and not get enough bouyancy on the anchor to whoosh it out.