They are actually extremely good anchors in the right conditions, but the right conditions are not very common. I have spent somewhere around 1000 nights anchored out hanging to various fisherman style anchors, mainly a 500 lb one on a 92', 125 ton vessel where we anchored through all the storms that came our way.
It is worth noting that there is a lot of variability in the design of these types of anchors. The fluke area and length varied a lot as well as the stock length and shank length.
As mentioned, the fisherman anchors have extremely low fluke area for their weight. The Luke models are especially bad about this. I would estimate that the 500 lb anchor had a surface area equivalent to a new generation anchor of 60-80lbs. I have seen much heavier fisherman anchors with even less blade area.
The arm which connects the fluke to the crown will vary a lot in length from anchor to anchor. Some of the long ones allow the fluke to bury itself very deeply which is very good. Others barely put the fluke under the surface and result in poor holding power.
Where the fisherman anchor really excels is in setting. Apart from smooth rock ledge, I have never come across a bottom where the fluke will not penetrate. This includes weeds, thick kelp, boulders, mud, sand, etc. In many of these situations, it is very hard if not impossible to get even the best new generation anchors to set.
The bottoms where the anchor does well are very hard bottoms where other anchors struggle to penetrate. Because of the low surface area, it takes a bottom with good structure to really get a lot of holding power. For example, one cove where we regularly sat out storms had medium density mud over clay. We would watch yachts continually dragging because their anchors could not penetrate the clay and we never had any problems because the anchor had dug into the clay which provided tremendous holding power. On the other hand, these anchors are terrible in loose sand and bottoms like that which provide almost no resistance to them.
Other than the very small surface area, the biggest issue with these anchors is that the chain has a tendency to wrap them up. When set, one fluke is sticking up so if the boat
does a circle around the anchor with the right amount of tension on the rode
, the chain can be wrapped around that fluke pulling the anchor out. I have probably only had it wrap 3 times out of 1000 and it has never pulled out on me but I could certainly see it happening. Before the anchor is set, either a fluke or one side of the stock will be sticking up which can again be wrapped by the chain. To make this worse, most vessels using these anchors will dump all of the chain in a big pile on top of the anchor because you can't really do anything else.
Stowing these anchors is certainly different than modern anchors. Some will break down so that they fit in a locker. If it is a primary anchor, the best thing to do is to "cat" it on the rail. If you look at how they are on traditional sailing vessels, this is what they are doing. To do this, a tackle is used to manipulate the anchor. Keep in mind that these vessels also literally drop their anchor as opposed to lower it. Windlasses had no reverse back then so chain was laid out and the anchor was dropped dragging the chain out the hawsepipe at high speed.
Many people who cruise
in places with extremely difficult bottoms still carry and use a fisherman anchor but it does not make a good primary unless you are willing to have an enormous anchor. As mentioned, 50 lbs is way too light for your boat.