Replacement Anchor much larger than Factory

[Tillsbury]

Originally Posted by wingssail

the owners feel more secure and claim to sleep better.

I can confirm that the quality of my sleep is directly related to the weight of my anchor. Although I don't keep two up front, just one huge one

[Mike OReilly]

Originally Posted by skipmac

Exactly. The calculations and the effect is much more complicated than how much weight is moved what distance on what size and displacement boat. Will depend overhang, beam, how the beam extends for and aft, and much more.

OK, I'm with you fellas .

https://www.youtube.com/watch?v=9xJkUyotSc4

[Mike Banks]

For that I would have a Manson Supreme of eighty pounds or thereabouts. I had a sixty on my trimaran, all chain rode to 200feet, plus a twenty five pounds mid-scope detachable kellet and that anchor never dragged--Drop anchor i untill it his ts bottom, pay out another ten feet and clip kellet on to chain. Ten pay out full scope of at least 5 to one.


Eighty pounds plus a kellet would hold a very large vessel in some really bad conditions in good holding--and the best of anchors will drag in loose gravel.

[Clivevon]

Having undue weight in the ends of the boat is about inertia, not where your waterline is when at rest. More weight forward gives more momentum so you will pitch more up and down & the boat will see saw more than if the weight is kept more amidships.
Having said that some boats like a bit of weight forward .to punch through and you certainly need to have your main anchor and your backup somewhere very readily at hand. Its a compromise....

[teneicm]

We are also on a 48 foot cat and purchased a Mantus 8 years ago. I decided to go one size up (105 pounds, I believe) and have never regretted it. The smaller anchor would probably have been fine, but if you have the space and the windlass can handle it, go up. I won’t say that an extra 10 kg has no effect on the boat’s performance, but certainly not enough for me to notice or to make me think the trade off wasn’t warranted. Get one of the Mantus anchor hooks for your bridle. They are great and never slip off!

[merrydolphin]

I had a Delta 55 as my primary for many nights at anchor (over a thousand ) with very rare problem. This was on a low profile 44’ mono hull. It was considered to be oversized. Not for a serious cruiser.

With my current boat, a 37 Tartan, I switched from a Delta 44 to a Spade 35. The Spade is clearly a better holding anchor in all conditions even with the size difference. So even though I liked the Delta, I always went oversized. A 48’ multi has MUCH more windage and mass than my 44’ mono. If you are spending any amount of time on the hook, get the best anchor that is out there I love the spade (but they are not cheap). And yeah, I always prefer oversized. That you have to go double the size in questionable IF you use a high quality modern anchor. I have been exceptionally happy with my spade and would take my 35# spade over the 44 delta any day. I think something like a 66# spade would be super good for your vessel. Even a 55 would probably be fine but, if your vessel and anchor tackle can handle a Lille extra weight, I like to sleep well at night! (ALL IMHO)

[Night_Sailor]

It is a smart move to go larger on the anchor, up two sizes for example. No one would criticize that. You would also want to perhaps upgrade your chain, or make appropriate changes there also. It is a good idea to have a short section of chain between the anchor and swivel, followed by more chain. Swivels seem to be a weak point, and they fail where attached to the anchor--so add a short length of chain.

Also, while most seem to think two anchors on the bow are better, if you are planning on Bahamian moor them add one when you go there. Most places it is not needed. The Bahamas are know for reversing currents so you need one anchor for each direction--people put both off the bow. A single large anchor might work just fine, but anchors are known to trip when the current changes if there is a long length of rode out. That is why too much rode can be dangerous at times. My advice. Just have one anchor on the bow. Add a second on the bow, normally stored amidships, when needed.

I also believe in having a large Fortress anchor in the back of the boat, with a short length of heavy chain and some plaited line on a French spool type winder. If you need to anchor in a hurry, if for example someone drags over you bow anchor and trips it, having one at hand in the back can save time and therefore your boat from disaster, or its also provide for a "fore and aft" mooring to put your bow into a swell.

As for primary anchor type, any spade type is good--Rocna, Mantus, or Ultra. I recommend Ultra. They are pricey but spade anchors are dirty, and you need a good finish to keep the mud off. The Ultra anchors have other very good attributes I won't belabor here.

[mcneilms]

Thanks Teneicm. I will probably do exactly that.

Originally Posted by teneicm

We are also on a 48 foot cat and purchased a Mantus 8 years ago. I decided to go one size up (105 pounds, I believe) and have never regretted it. The smaller anchor would probably have been fine, but if you have the space and the windlass can handle it, go up. I won’t say that an extra 10 kg has no effect on the boat’s performance, but certainly not enough for me to notice or to make me think the trade off wasn’t warranted. Get one of the Mantus anchor hooks for your bridle. They are great and never slip off!

[thinwater]

Originally Posted by wingssail

I guess I'd like to read a couple of these tests, searching on this forum for "anchor holding test" came up with nothing, and internet search came up with one west marine test.

Do you know of some?

Every sailing or boating mag, most of them more than once. Boat US several times. Most manufactures link to one of several. Search this forum. You should be able to find about 10 within 10 minutes.



Bear in mind that procedure, bottom type, and data analysis make a huge difference. Often the data does not reflect real world differences in reliability on a variety of bottoms types, since reliability in setting and resetting is very hard to measure. Most anchors do well in nice mud or sand. Very hard, very soft, weed, and rocks separate the fair from the good.

[FerrariSailing]

I put the biggest Rockna anchor that would fit on my 46ft Schionning cat plus 60mtrs of heavy link chain after dragging a smaller spade type anchor a few times.
I think Rockna will suggest sizes per boat length, then I would go at least two sizes bigger for a cats windage.
I use a bridle off the fwd crossbeam, each side is the length of my cats beam 7mtrs. Now I sleep well.

[pbmaise]

Everything depends on whether you are not afraid to venture out in conditions that make other sailors stay in port. Further will you attempt to anchor in open areas where winds can blow you to shore? With my new 70 KG Rocna and all 100 meters of chain I still dragged 1 kilometer in a squall. I wasn't too concerned since I had several kilometers of coast line that ran parallel to the direction I was plowing. By monitoring my depth and distance from the coast I knew I was not in trouble. I finally got the vessel to stop dragging by alternating engine on several seconds. Mind you, I had to sit on the bow in the thunderstorm to make sure we didn't over run the chain. I passed hand signals to someone midway.

Ah the things they never teach you in a sailing book.

I am already at maximum anchor size, so my solution if I intend to be in conditions like this again is to change the chain to a much heavier chain.

Needless I, and or my crew, stay aboard when anchoring in difficult situations.

In one semi-protected bay I wanted to take the crew to shore for dinner. I hired two local crew members off a ship to man my vessel while we were off the vessel.

It is part of the price of having a big multi-hull and the desire to sail when the wind is blowing hard.

In the Philippines when I anchored near shore for several months I attached 2 -55 gallong plastic drums to the chain about 30 meters from the anchor. I then filled them full of sand. This weighted my chain down far more than any heavy anchor could have done. Of course this procedure takes several hours to set and then several hours to take down. So I have only employed this technique twice. It worked fantastic. During a blow the barrels would be picked slowly up off the seabed until they were several meters up. Then when the wind let up slightly, the vessel rushed forward as the barrels dropped back to the sea floor.

You employ more radical the bigger your multi-hull and the bigger the winds you encounter. Now that I am back in Malaysia I don't have the wind problem. The phrase in the Philippines...is It is more fun in the Philippines.

That applies to anchoring too.

Back a few years ago, every single mult-hull in the King's Cup Race in Phuket was blown onto shore. Most crews had gone to shore to party. If I was in that race, believe me I would have had no trouble since I employ tactics like I outlined to actively protect the vessel. We certainly would not have let everyone go to shore.

[wingssail]

Originally Posted by pbmaise

...Back a few years ago, every single mult-hull in the King's Cup Race in Phuket was blown onto shore. Most crews had gone to shore to party. If I was in that race, believe me I would have had no trouble since I employ tactics like I outlined to actively protect the vessel. We certainly would not have let everyone go to shore.

Generally the winds at Kings Cup blow offshore, so the danger, if you leave your vessel unattended is that it may be gone in the morning, the holding not being good. A helicopter is available to go searching for errant vessels, for a price. When found they send a ship after them.

We left a crew member on board; he was happy not to have to pay for a hotel room (I was not buying), but after two nights he grew tired of missing the parties and he came in and strayed with a mate.

The winds were not strong and anyhow we anchored well. But the next year the winds shifted onshore and many of the fleet were ashore in the morning. But we were no longer in Thailand, having taken our trophy the previous year and moved on.

Bruce 44lb, all chain 5/15 HT

[daydreamer]

We have 42' 25,000 lb cat. We put a 65lb Mantus on it the first year they came out. Love it, love it, LOVE it! I would buy the same anchor again, and and recommend a Mantus to everyone I know and meet.

Our anchor would hold your bigger boat just fine in any normal circumstances. But you don't always get to choose your circumstances, so I would go with a larger size. Probably the 85, but I would seriously consider the 105 too, based primarily on how well it would fit the bow roller.

[Zzmeyer]

Originally Posted by mcneilms

I have been looking at a 48' Catamaran and the factory anchor is a 55lb Delta.
When looking at the Mantus site, it seems a 85lb is recommended.

What gives? Just the manufacturer saving money?

Thanks,
Scott

The difference in weight is 30 lbs. 200 feet of half inch chain weights more than 500 lbs.

[com5984]

I too am looking at a new anchor, I have a 50' cat but it only weighs 8000kg. I'm looking at an ultra either 60lbs or 77lbs. If I go on the manufacturers recommendation for the weight 16000lbs it assumes the length is only 36' and if I go on boat length it assumes the weight is 47000lbs.
I've ordered the 66lbs which is 23500lbs and 41' but the dealer who has been very helpful suggests I go with the 77lbs which is 34500lbs and 45'.
It currently has only 100' of 3/8" chain which I want to increase, which adds more weight. My dilemma is not just weight but the bigger anchor is 800 dollars more which for the safety of boat and crew is nothing but there are plenty of other things I need so if I can get away safely with the 60 I would be happy.