Anchor - Sealine

[asteven221]

Our boat is a Sealine F44 and in common with lots of Sealines has an anchor storage arrangement where the anchor is stored hidden under the bow (sprit).

I think the anchor is light at 10kg (Delta) and would like to upgrade to a heavier version.

It looks as if it isn't possible given the storage arrangement and was wondering if anyone else has managed to upgrade their anchor.

Do others think that the factory fitted 10kg is sufficient? Do Sealine know best?

I am going to upgrade the current 30m of chain to about 60m. If it's an 8mm chain, then maybe go to 10mm, assuming the windlass will work with it okay. I realise a change in the gypsy will probably be required.

Thanks.

 

[hlb]

I'd stick with the same anchor and chain size. Except as you sujest, fit 60 metres of chain and let out more than the recomended scope. Doubt if you'll ever move then.

 

[PRH]

Our boat is a Sealine F44 and in common with lots of Sealines has an anchor storage arrangement where the anchor is stored hidden under the bow (sprit).

I think the anchor is light at 10kg (Delta) and would like to upgrade to a heavier version.

It looks as if it isn't possible given the storage arrangement and was wondering if anyone else has managed to upgrade their anchor.

Do others think that the factory fitted 10kg is sufficient? Do Sealine know best?

I am going to upgrade the current 30m of chain to about 60m. If it's an 8mm chain, then maybe go to 10mm, assuming the windlass will work with it okay. I realise a change in the gypsy will probably be required.

Thanks.

I have got an F43 and had the same idea. A very nice man at the local chandlers lent me the next size up and it didn't fit. As with all Sealines it will require some cutting of the GRP.

Why did I try, well I anchored at Swanage in amongst a lot of other boats (Red Arrows day) and the anchor wouldn't hold. It was very windy for Swanage but I have never had any problems there before with a danforth on my old boat.

Sometimes it is just not possible to let out more chain due to the proximity of other peeps.

In answer to your other question, no I don't think the factory fitted anchor is man enough for all occasions.

If you find the answer then please post it on the forum.

 

[asteven221]

Thanks for the comments guys. PRH. Thanks for letting me know you tried the next size up as that saves me the bother as that was my next move.

Given that I have not heard of lots of Sealines on the rocks then I guess we all choose a nice sunny day to anchor or go into a marina for thje night.

I will certainly post if I can come up with something that works better - without GRP surgery.

 

[DavidJ]

Got the same problem with my S37, I notice that the S38 had the bigger anchor so Sealine had recognised the need for sizing up although the S37 anchor is inside the recommended range for Delta's.
The guy 'what does my boat' in Spain has done the conversion for an S43 but said that he would never attempt it again so I guess it didn't go well.

 

[JKay]

We have had 5 boats total weight at least 18 and 1/2 tonnes rafted up on a 10kg Delta through a change of tides in the Wash with 10mm chain
I feel the anchor is fine go up on the chain as you and hlb have suggested and you'll be fine
Depending on the bottom

 

[hlb]

Far to many folk worry about anchors, but not about chain. It's the chain that stops you, not the anchor. Think about it. If you have 30 M of chain and the depth shows ten metres. That's usually from the keel. So you need to let about 4M out, before you get to the starting line. So your maximum anchoring depth according to RYA is about 6 metres. Depth X 4.

Depth sounder + 1 metre is 11 metres of water x 4 is 44 metres of chain minimum. So you need about 47 M out, lets call it 50, as minimum.

Most divers on here will tell you anchors nearly never "set" and just lie there on the surface. Proof that the chain did the job, nearly never the anchor.

 

[Deleted User YDKXO]

I had a F43 a few years ago and had the same experiences as you. The 10kg Delta fitted as standard is far too light for this size of flybridge boat with it's substantial windage. I looked long and hard into whether the anchor size could be upgraded and I came to the same conclusion as the others. It can't be done. However, you are right to be looking at increasing not only the length of chain you carry but it's weight. At least go to the maximum chain size the windlass is rated for; yes it means changing the gypsy but thats relatively cheap so its a no brainer really.
I upgraded the chain size from 8mm to 10mm on my last boat (Ferretti 46) as well as upgrading the anchor. It proved to be very worthwile and I never had any anchoring concerns afterwards. IMHO, increasing the chain weight improves anchoring performance in 2 ways. First, my observations in the Med (normally I swim out to inspect the anchor) is that, even in quite windy conditions, most of the chain lies on the seabed (assuming at least a 1:3 scope) and upgrading the chain size simply adds useful extra deadweight to to the holding power of the anchor. Second, increasing the weight of the chain increases the catenary effect of the chain which means that less shock loading caused by the boat shearing from side to side is transmitted to the anchor

 

[craigsmith]

Our boat is a Sealine F44 and in common with lots of Sealines has an anchor storage arrangement where the anchor is stored hidden under the bow (sprit).

I think the anchor is light at 10kg (Delta) and would like to upgrade to a heavier version.

Your anchor is hopelessly undersized for your boat and the obvious cause of any dragging experiences assuming adequate scope at the time.

The idea from the likes of HLB that "the chain stops the boat" and the anchor does nil is complete and utter nonsense. An adequately sized Delta in good holding will resist enough to almost completely straighten any reasonable chain rode.

If you leave the 10 kg on the bow, is it practical for you to man-handle a larger anchor when necessary? It's not hard to throw about a 20 kg for instance if you have space for it somewhere.

 

[MapisM]

Most divers on here will tell you anchors nearly never "set" and just lie there on the surface. Proof that the chain did the job, nearly never the anchor.

Mmmm... those might be good divers but poor helmsmen, surely?
Since setting the anchor is an essential part of a proper anchoring maneuver, if they see it lying on the bottom "unset", they should rather return onboard and make a proper maneuver, than jump in any conclusions...
Anyway, at times I also did drop the hook without bothering to anchor properly, with no wind or just a very light breeze, when I knew in advance that I was staying shortly, just for a swim.
And yes, in those conditions I mostly saw the anchor still lying flat on the bottom, but I would think that this is mainly due to lack of pull, than to the holding power of the chain alone.
All that said, in this specific case I also don't think that the OP needs to change the anchor, and I agree that the 60m of 10mm chain route is the more appropriate.
Not that I don't see why someone who sell anchors might have a different opinion...

 

[JKay]

"If you leave the 10 kg on the bow, is it practical for you to man-handle a larger anchor when necessary? It's not hard to throw about a 20 kg for instance if you have space for it somewhere."

Craig that will not work for a Sealines setup as prev posted

 

[craigsmith]

All that said, in this specific case I also don't think that the OP needs to change the anchor, and I agree that the 60m of 10mm chain route is the more appropriate.
Not that I don't see why someone who sell anchors might have a different opinion...

Well, we can put some numbers on it.

Let's imagine the OP's boat in a depth such that the bow roller is 5 m above the seabed, with all 30 m of his current length of chain deployed (for a scope of 6:1 all chain).

In let's say 25 knots of wind, his 44' boat can be expected to put roughly, in the order of, peaks of about 400 kgf of tension on the rode.

With this tension, the 8 mm chain is completely lifted off the seabed and the angle of pull on the anchor is 6.8 degrees.

If we model the same situation but change the chain to 10 mm, the angle of pull is reduced to 5.3 degrees, as a result of the increased catenary effect of the heavier chain.

This decrease of 1.5 degrees will have some small incalculable (trivial) benefit to the anchor's ultimate possible performance.

Change the 10 kg Delta to a 15 kg Delta and you up the holding power by 50%.

Go figure.

 

[vyv_cox]

It's the chain that stops you, not the anchor.

Most divers on here will tell you anchors nearly never "set" and just lie there on the surface. Proof that the chain did the job, nearly never the anchor.

This is untrue. My anchor connector failed due to stress corrosion (i.e. not due to being overloaded) At the time the wind was about force 3, we were in about 2.5 metres of water with about 20 metres of chain out. Immediately the connector failed, which we heard, we began to slide backwards quite quickly. Then drag effect of the chain alone was almost negligible.

The reason that the anchor is lying on the bottom and not dug in is because the boat was not reversed to set it. I go astern at 2000 rpm for at least 30 seconds to ensure that this has happened.

 

[hlb]

This is untrue. My anchor connector failed due to stress corrosion (i.e. not due to being overloaded) At the time the wind was about force 3, we were in about 2.5 metres of water with about 20 metres of chain out. Immediately the connector failed, which we heard, we began to slide backwards quite quickly. Then drag effect of the chain alone was almost negligible.

The reason that the anchor is lying on the bottom and not dug in is because the boat was not reversed to set it. I go astern at 2000 rpm for at least 30 seconds to ensure that this has happened.

Well, explain to me how whenever I retrieve my anchor, the chains snaked all over the place, yet 400 HP would not straighten it.

 

[MapisM]

Well, we can put some numbers on it.
...

Interesting reading.
I never bothered to do any kind of math on anchor holding, and my previous suggestion was just based on experience.
Yet again, on the same basis, I can tell you that in one of my favourite anchoring bays it's not unusual to have 20+ knots of wind, with gusts up to 30+.
Such wind comes from the land, so the sea surface is unaffected and you can still enjoy the stay even in such windy conditions.
Sandy bottom, 5 to 6m depth. I don't have a bow roller, but the point of traction of the chain on the hull is maybe 1.5m above the w/l. Let's say overall 7m above seabed.
In such conditions, I normally deploy 50m of 10mm chain, and the boat is a rather heavy (35T or so) 53 footer.
Now, I'm not saying that the anchor is unnecessary - and that's not what I said in my previous post, either.
But while snorkeling around in those conditions, I never saw the chain completely lifted off the seabed, as per your assumption.
I did see the chain swinging sideways on the sand, sometimes (albeit rarely) for its whole length, but I can't remember of one single time where I've seen the chain lifted from the bottom in the last 6 to 8 metres.
Therefore, either the wind for some reason always stops blowing while I'm swimming, or the assumptions of your calculations don't match the reality.

Anyway, I'm sure you will pardon me if defining the anchor fitted by a reputable builder as hopelessly undersized (when the OP didn't even mention in which conditions he wants to anchor), to my simple mind sounded like a biased opinion.
In the same bay I just described, there are other days when I could remove the small grapnel anchor from the 3m of 6mm chain (plus some rope) which I keep in my tender, and that alone would be still sufficient to anchor the whole boat...

 

[JKay]

Craig hasn't read all the posts as the Op cannot fit a bigger anchor,end of story
on a bottom that suits a Delta the anchor is fine,seaweed and rock another story !!

 

[hlb]

Craig hasn't read all the posts as the Op cannot fit a bigger anchor,end of story
on a bottom that suits a Delta the anchor is fine,seaweed and rock another story !!

That why I suggested more chain. As others dont seem an option.

Still a believer in chain does the job. Do you really want the anchor constanly getting jolted.

 

[JKay]

That why I suggested more chain. As others dont seem an option.

Still a believer in chain does the job. Do you really want the anchor constanly getting jolted.

agreed the Op cannot fit a larger anchor and the heavier chain AND more of it WILL help

 

[hlb]

This is untrue. My anchor connector failed due to stress corrosion (i.e. not due to being overloaded) At the time the wind was about force 3, we were in about 2.5 metres of water with about 20 metres of chain out. Immediately the connector failed, which we heard, we began to slide backwards quite quickly. Then drag effect of the chain alone was almost negligible.

The reason that the anchor is lying on the bottom and not dug in is because the boat was not reversed to set it. I go astern at 2000 rpm for at least 30 seconds to ensure that this has happened.

Hmm, a bit sad that you did not check your gear till it got that bad.

20 Meters of chain out. Why bother. Why do folk scrimp so much on chain. It costs so little to let a bit more out. Are folk hooked on RYA minimum depths

 

[craigsmith]

Yet again, on the same basis, I can tell you that in one of my favourite anchoring bays it's not unusual to have 20+ knots of wind, with gusts up to 30+.
Such wind comes from the land, so the sea surface is unaffected and you can still enjoy the stay even in such windy conditions.

That your anemometer is measuring 20 or 30 knots at the top of your flybridge or wherever it is says little about the wind speed on the hull; your own comments about the sea surface seem to support this. In any case, my comment above allowed for peak loads in a bit of fetch or surge... in dead flat water with a heavy boat like yours the peak tension would be lower for sure and there's little contradiction.

In any event, my point was to draw the example. With 400 kgf of tension in the line, just as a reasonable level to consider, the difference between 8 and 10 mm chain is utterly trivial. As one increases the forces, the differences become less and less (while the difference between a 10 and 20 kg anchor remains about 100% in any situation whatsoever). My example was a rather nice-for-windsurfing 25 knots - what about an unexpected 40 knot squall?

Incidentally, it is reasonable to talk about the anchor in question at the same numbers. A Delta is quite capable of holding up to about 100 times its weight, so we may expect it to sustain a tonne or so but only in excellent holding. However, in very soft mud, I would not expect a 10 kg Delta or any other anchor to resist 400 kgf. It just will not hold. Way too small.

I realize there seems to be a consensus that changing the anchor is impossible, but a solution that makes no real difference is not a solution. If the OP is using adequate scope, there is nothing much more he can do with regard to the rode that will have any appreciable benefit.

P.S. Does anyone have a decent photo of the bow arrangement in question, or a drawing? Is there any reason you couldn't drop the rollers down and forward, on extended cheek plates, to permit a larger anchor? Accepting that it would all be visible of course.