Setting and retrieval
The Rocna is designed for good behavior on typical bow rollers, and should self-launch and self-stow without drama.
Once on the seabed and being relied upon to hold the vessel secure, the Rocna differs from other anchors in the behavior that may be expected from it during both setting and retrieval. The manner in which it sets itself, and just how well set it can be when it comes time to recover it, are aspects that can surprise people.
Contents
Deployment and setting
This page discusses only the actual setting of the anchor, and does not deal with other elements of the rode and its deployment, including chain, rope, scope ratios, snubbers, windlasses, chain stops, and counting chain. For more on those topics, please refer to their respective sections.
Launching from bow rollers
The Rocna is intended to self-launch itself from the majority of bow rollers, even if the anchor is stowed in a horizontal orientation (it does not need to be angled downward in order to slide forward when released). Our main website features a video demonstration of the Rocna self-launching and self-stowing.
Bow roller design affects how effectively the anchor will self-launch. The bow roller assembly design section of the Rocna Knowledge Base has extensive information and advice on this topic. Also, a long length of chain suspended between the shank and the windlass may be heavy enough to hold the Rocna back and deter it from self-launching.
| “ | I read the anchoring instructions on www.rocna.co.nz and noted that they recommend to slowly reverse to bed the anchor, and that the anchor grips faster than other types. Yeah right! First anchorage was Izzy Bay, Rangitoto Island – Pauline did her usual reverse circle at modest speed and I nearly shot over the pulpit as the anchor set so quickly in the mud. Wow! I'm sure my arms are a little longer. | ” |
| — Tom Niblock & Pauline McAuley, SV "Shanaro" (NZ) | ||
| “ | One of the Rocna owners I spoke to came up with the following tale... He had just greased his windlass, making it far quieter than he was used to. He motored fairly briskly astern but because he couldn't hear the chain running out, he thought that the anchor had hung up in the roller. He stopped running the windlass out but continued to motor astern. When the anchor dug in, the boat stopped so suddenly that everyone in the cockpit lost their balance. There was a crash from below which turned out to be some glasses that had smashed inside their locker... | ” |
| — Vyv Cox, UK / Mediterranean | ||
Setting the anchor
The Rocna will set in most bottom types, including hard and difficult to penetrate seabeds such as hard sand, hard clay, and thick grass and weed.
If you are used to other anchors, especially old generation anchors, a Rocna will almost certainly set much more quickly and decisively than you will consider normal. Take care when reversing your boat under power and do not build up too much speed, as the anchor will grab quickly and the resulting shock can easily damage equipment or even injure personnel. Windlasses are particularly prone to damage, as their shafts are not intended to endure such shock loading. For this reason, a Rocna should not be set with the chain still held by the windlass – stop it with a chain stop or take the load off with a spring line.
Extremely difficult bottom types
Some submarine environments present extreme challenges for anchors. These are rare, and this section deals with unusual conditions which most boaters will never encounter, and in which most other anchor types would never work at all.
The harder the seabed type, the more difficult it is for an anchor to set. The Rocna is accomplished on almost all seabed types, but there are some environments that will present challenges even for it. Rock and coral (nb: never anchor on live coral) are obvious problems, where no anchor can perform reliably. A Rocna will find a rock or crevice to grab, just as well if not better than any other type. However, it could also easily become fouled. On such a seabed, we suggest the use of a buoyed retrieval line.
In another form, flat and solid slabs of rock, or coral pan, may offer no terrain on which to grip. In this case there is little that can be done other than depend on the dead weight of the anchor and resulting friction on the bottom. This is one reason some cruisers like to have very over-sized anchors.
Very hard sand, or a thin layer of sand over hard clay, can be very difficult for an anchor to penetrate. In this case, the Rocna can suffer slightly from its own performance – in the initial setting stage, its tip begins to bury and immediately offers some resistance. In a hard substrate, this resistance could be enough to quickly straighten the rode, which usually does not occur until the anchor is more fully set. This results in an upward force being applied to the anchor, which simply lifts it off the bottom. The solution is not to try to set the anchor too firmly – rather, let it get a slight bite, then leave it alone. The pitching of the boat will tug at the rode, and work the anchor into the bottom in a more gentle fashion. Meanwhile, anybody trying to anchor next to you with an old generation plow or claw has long since given up and moved elsewhere!
Note that anchor testing demonstrates that the quality of an anchor's set improves gradually over time, for some while after it is initially set. This is because the anchor slowly works its way deeper until it is happily settled. A Rocna will usually set very quickly and offer immediately excellent holding power, but it too will benefit from this effect.
Retrieval
| “ | That night I napped in the watch berth and saw 55 knots on the Airmar coming from the SE with about 3 miles of fetch... Due to the lack of room, I only had about 200' of scope out in 45' of water at low tide. The swells built to 3 or 4 feet and lots of trees and lumber were coming down on us from the flats at the south end of the bay. Several times I started the engine and motored to the side while anchored to avoid an oncoming tree! We noticed that several boats had blown up on the beach during the night. Later the next morning the wind had died down some and we decided to move into the marina. I motored up into the wind and retrieved rode... With the still gusty conditions, I could get all but 70' back, so I tied the rode off to the Samson post and powered ahead to unset the anchor. After many unsuccessful tries, I decided I must have hooked the cable to Protection Island. By this time the wind had backed to the West and was increasing again, so I kept the rode short in hopes that the new wind direction with gusts to 40 knots would free my anchor. No such luck. I located a diver... He suited up and went down the rode... After a while he resurfaced and asked what the heck kind of an anchor that was. All he could see was part of the shank, but he dug down in the mud to the fluke without finding the cable. He then walked around the bottom to see if he could find the cable. It was about 5' South of my anchor. He told me to just keep pulling harder. With knowledge that we wouldn't damage the cable and a lot of powering over the top of the anchor, we were able to unset it. Since I set the anchor to the south and backed down on it to the north, and since the greater part of the storm was from the South, this tells me that the Rocna dug in and stayed put... even with short scope and swells. | ” |
| — Rob Bonner, MV "Maritime" (USA) | ||
Concern with ability to recover a Rocna is not unusual, which is something that has surprised us. Put simply, the better any anchor holds, the harder it is to retrieve – an inescapable connection. However, our video shows Peter laboring to recover a Rocna 10 after testing, a display which raises this question frequently.
With regards to the instance shown in our video, one must realize that...
- This is after over a tonne of force has been applied to the anchor. This is not at all normal, as usually the force applied by the boat would be much less. It will therefore normally be easier to recover, and if a tonne ever is applied to it, you will probably not be bothered if it requires a bit of effort to break free!
- This is a 10 kg (22 lb) anchor which is rated for a boat of up to 10m (33') – such a boat should have little problem pulling it out. Even if it was this stuck, the user would simply pull the rode in as far as possible, then once the rode is vertical let the wave action on the boat work the anchor out over a few minutes, or power it out by driving over the anchor in the reverse direction to which it was set.
Aiding recovery
A buoyed retrieval line can be used if retrieval is a serious concern. Foul ground where the anchor is likely to become stuck may necessitate this.
Other techniques exist, such as attaching the rode to the hole at the crown of the anchor shank rather than the rode attachment point. A cable tie or similar is then used to hold the rode at the correct attachment point. Under normal usage, the pull on the anchor is such that the rode attachment point is more or less in line with the front of the anchor; however, if significant force is applied to the anchor during retrieval, the cable tie breaks, and the rode now pulls from the attachment at the crown of the shank, similar to a trip line. This sort of technique may be appropriate for fishing or other short term anchoring, but is not recommended for normal usage, as it can 'work' when not desired (such as after a wind shift). Furthermore, the chain attached to the front of the anchor upsets its weight balance, which can detract from its setting performance.
