Anchors for Catamarans

[lo2jones]

Amen on the Bruce. I’ve never had a problem.

[Sociaboat]

All interesting reading. Here’s another real world example.

Tek35 cat, probably ~8500# cruising trim
2 15# aluminum spades (on rollers just port side of center on front beam) on 25’ heavy chain and another 150 5/8” line.

I chose the aluminum spades because I haul them by hand. Never dragged except in heavy grass. But I set them carefully in good spots. I don’t expect to be able to anchor on any bottom. When I’m cruising I anchor once or twice a day often. Making it easy was a priority.

I had problems with the aluminum reacting with the lead in the tip, causing th anchor tip to rupture, necessitating finding someone who would reweld it. I also bent a shank when trying to haul it up using the force of buoyancy when it must have been wrapped on something. Easily fixed, albeit undoubtably with some loss of strength.

I have a bridle permanently rigged with a caribeiner (sp?) in the middle. On my anchor lines I took 18” pieces of line and braided both ends into the the anchor line, forming a loop so that the splices both pull in the correct direction. The bridle all stows in a small bag on the nets and the legs clip in tight to the caribeiner , in turn clipped to the nets. It’s quick, it’s easy to rig, you are still hanging on your anchor line and there is no abrasive contact between your bridle and your anchor line. Quick to set, quick to get in in an emergency. You can clip two lines into it for achoring for wind or tide shifts. Sorry I don’t have a picture. Occasionally the loops bind for a second on the bow roller. Slack line and pull again and they always free up. Of course, none of this would work with a windlass.

That’s my system.

-Jeff

[roscheetham]

We have a Nautitech 442. Throw out the FOB which will drag if the boat turns through 180 degrees even if you have set it really hard. Buy a Rocna 20kg. You won’t be disappointed. Ours has taken us around the world and never failed.

[Perfect Ride]

Originally Posted by CaptRehab

Thinking of an upgrade such as a Spade, Rocna, or Mantus. I think a 25 Kg spade would fit but probably not a 25 kg Mantus. Anyone have experience with the FOB anchor vs the others?

Running a 33kg Rocna on a 44i Antares and have had excellent results. We anchor 90% of the time over the last 5 years of world travels. Rocna's Rock!

[Rimica]

Just for the record. I have a Spade on a 51 feet catamaran. It held no problem for 4 days in 50 knots winds in Greece. I was in 5 meters of water. I put 50 meters of chain and the bottom was mud.


I now have trust in my anchor. Nothing like experience with a bit of kit to judge if its a good piece or not.

[Tupaia]

The primary difference between a Spade and a Rocna is the roll-bar on the latter.

On the face of it the roll-bar sounds like a good idea, it flips the anchor into the right orientation when being set. The disadvantage is that on soft bottoms the same roll-bar will prevent the anchor from penetrating beyond the roll-bar. The Spade on the other hand will continue to dig down until it and a good proportion of the chain are below the bottom.

I bent the shank on my aluminium Spade. After being unable to shift it following a blow. Diving on it, to ensure it was not snagged revealed that the entire anchor was buried to a depth of 2 feet. It took a lot of effort to extract it and as a result the shank was bent. I would therefore choose a steel Space as a replacement.

The sharp point on the Spade is also very effective at breaking through the hard crust on coral sand.

There is no perfect anchor for all conditions but both these are good examples of modern anchors.

[Bon Temps]

I did a lot of research since my 39 foot Seawind cat kept dragging. I came up with a Rocna and have been very happy with it. I would suggest that you get one size larger than what they recommend because cats pull a lot more wind than a model whole

[mikaelnygren]

Sarca-Excel No 8 for me, used it for 8 years and very happy.

[SharAndy]

We promptly dumped our new Delta for a 55 lb Rocnar when we purchased our our 39' power cat last year. Formerly, we'd cruised full time for 6 years from Canada to and thru the Caribbean in all kinds of weather, (Christmas winds, squalls, catabolic winds, etc) currents and muck with a Rocnar on our 50' trawler with nary a mishap. Would and did, stake our lives on that Rocnar!

[chrisr]

Originally Posted by mikaelnygren

Sarca-Excel No 8 for me, used it for 8 years and very happy.

Get's my vote too

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cheers,

[TabbyCat]

14 years cruising our MaineCat 41 (10 tons) with a Rocna 25kg our primary, and a Fortress as backup if we need to stern anchor, or anchor in grass. We're very happy with both. Almost as important as the anchor is the size chain - we increased from 5/16" to 3/8" and that really helps us sleep better!

[mikereed100]

Originally Posted by Tupaia

The primary difference between a Spade and a Rocna is the roll-bar on the latter.

On the face of it the roll-bar sounds like a good idea, it flips the anchor into the right orientation when being set. The disadvantage is that on soft bottoms the same roll-bar will prevent the anchor from penetrating beyond the roll-bar.

This has not been my experience. We had a 33kg Rocna when we were in SE Asia. Anchoring is soft mud we would allow an extra 15-20 minutes when pullling anchor to raise the thing through the mud. If it had blown more than 20 knots the anchor would be several feet deep. We would have to pull the rode up short and then I would jump up and down on the chain between the roller and windlass to ease the anchor out of the mud. Pull up tight on the chain with the windlass and repeat.

That said, the roll bar can be a nuisance when anchoring in areas with loose blocks of coral, kelp holdfast, rocks etc. These can become lodged in the space between blade and rollbar, preventing the anchor from setting well.

We moved the Rocna to our trawler and replaced it with a slightly larger Mantus, which has also served us well. However, when we get to Oz we will likely replace the Mantus with an Excel, eliminating the roll bar and keeping the Mantus as a backup.

[Iains boatyard]

Having had an Ultra on my two previous Cats a 40 ‘ and a 45’ at 27kg now a 60 kg on my power mono at 20 tons reckon you cannot beat them.
Have anchored where Rocnas have failed.
Depends a lot on your technique.

[chrisr]

at the risk of going a little off-topic here, how many folk out there lower a secondary weight down along the anchor chain...sometimes called a Kellet ?

i know why i have used such, but what do you think is the benefit/s ?

how useful is such ?

how much weight do you use ?

cheers,

[mark_morwood]

Originally Posted by chrisr

at the risk of going a little off-topic here, how many folk out there lower a secondary weight down along the anchor chain...sometimes called a Kellet ?

i know why i have used such, but what do you think is the benefit/s ?

how useful is such ?

how much weight do you use ?

cheers,

Here's what I think is a pretty reasonable analysis of why kellets are not doing what a lot of people might think they are. I've also included a link to an analysis of catenary which I think is also useful. If you want to add weight, add it to the anchor where it can make the most difference, not the rode.

https://www.petersmith.net.nz/boat-anchors/kellets.php
https://www.petersmith.net.nz/boat-anchors/catenary.php