Emergency stern anchor sizing

[Panope]

I agree with Thinwater's recommendation to spin the boat into the wind/away from shore and use the bow anchor.

That said, I tested the "emergency stop" concept using a Fortress FX-16 with 12 feet of chain and 80 feet of 9/16" Nylon. 15,000 pound boat motoring ahead at 3.6 knots.

As can be seen in the video, the anchor sets and stops moving in only a few feet. I have no idea how far the nylon stretched and I did not have a way of measuring load. My gut feeling was that line was no where near breaking.

The potential for injury (fingers being crushed or cut off) was high.

Steve

https://www.youtube.com/watch?v=qtD4DBjjE0w&t=49s

[thinwater]

Originally Posted by Panope

I agree with Thinwater's recommendation to spin the boat into the wind/away from shore and use the bow anchor.

That said, I tested the "emergency stop" concept using a Fortress FX-16 with 12 feet of chain and 80 feet of 9/16" Nylon. 15,000 pound boat motoring ahead at 3.6 knots.

As can be seen in the video, the anchor sets and stops moving in only a few feet. I have no idea how far the nylon stretched and I did not have a way of measuring load. My gut feeling was that line was no where near breaking.

The potential for injury (fingers being crushed or cut off) was high.

Steve

Sounds right. His boat is twice as heavy and I quoted a slightly higher speed. It is also worth noting that some of the anchors failed to bite at speed.

[Red Sky]

Originally Posted by mickt243

Why are you “throwing” an anchor?

Exactly.

[scherzoja]

If you follow through with your idea and get a stern anchor, make sure you have the gear to manage that anchor. The anchor alone is not enough. You need appropriately sized roller (fair lead to the water), cleats (large enough, sufficiently backed), locker to keep the rode (water drains, isolated so non-related gear won't tangle), secure place to store the anchor when not in use (but available quickly for when you need it and the bow anchor won't do). Design the stern anchor system to be as easy to deploy/retrieve as the bow.

If it's easy to use, you will use and won't get hurt by it. A lot of force can be placed on an anchor so make sure your stern can handle it.

Once you have your stern anchor system set up and it is easy to use, you'll wonder why you went so long without it.

[thinwater]

Originally Posted by scherzoja

If you follow through with your idea and get a stern anchor, make sure you have the gear to manage that anchor. The anchor alone is not enough. You need appropriately sized roller (fair lead to the water), cleats (large enough, sufficiently backed), locker to keep the rode (water drains, isolated so non-related gear won't tangle), secure place to store the anchor when not in use (but available quickly for when you need it and the bow anchor won't do). Design the stern anchor system to be as easy to deploy/retrieve as the bow.

If it's easy to use, you will use and won't get hurt by it. A lot of force can be placed on an anchor so make sure your stern can handle it....

And everything he said. If you get a finger or leg caught by the rope when it is running out you're going to loose it. There can be nothing makeshift about the rigging. And consider that the boat is probably gaining speed all the while.

[Unity]

Thanks everyone for the thoughtful comments. Of course "throwing" was a figure of speech ... though I have seem some crazy people literally throwing their anchors! And of course I would turn into the wind to slow her down, try the engine, raise sails if down, etc.

But my thinking process here was more about worst case situation handling. Maybe my sails are wrapped or jammed (they are all furled, including in-mast), or maybe my windlass has lost power/failed. Sure - turn into wind and slow her down, but was thinking working from transom would be safer and faster than trying to get my bower (over-sized Spade on 300' chain), or even my secondary (standard sized Delta, chain/rode combination), down from the bow (which is 50 feet forward). Just walking through my redundancy options, while also thinking about the functional value of having a rigged stern anchor "at the ready".

But your points on the loads (though I am adding massive chain plates aft along both sides on the hull to take the load of a JSD), and risk of losing ones fingers (I am kinda attached to them...!) are spot on and provide reason for pause...

I think instead I will focus more on selecting a good anchor for the transom for when I need to control swing and not so much on using it in a so-called emergency. Given my current inventory, I think adding a Fortress to the transom will be a great complement to my ground tackle options. Though maybe I should but it on the bow and move the Delta aft?

Thanks all! Chris.

[Unity]

So I sized out a Fortress... the "correct" size is the FX-55, but assuming I want it for storm conditions as well I thought I'd go up one to the FX-85. Add on to that 9/16 chain (that is the size for my windlass), at say 50 feet. That's 150 pounds, before we get to adding any of the plait rode! So when hauling in by hand (on the transom), that would be a struggle (when deploying on the bow, I'll have the windlass w/capstan, so no biggie).

So I could drop back to say the FX-55 and only 15 feet chain, which comes down to just 65 lbs - quite manageable. But now it isn't storm friendly - it's a day anchor or a stern anchor deployed in combination with a bower.

Now I'm down to a classic problem. Reduce the weight to make it manageable, or keep it strong to keep the boat safe!

I hate the idea of doing both, but that may end up being the best answer. The 100 pound Spade as my primary, and the FX-85 and a 65 pound Delta sharing as my second anchors (either using Spade as primary in soft mud, with consistent wind directions, or using dual anchors set out 45 degrees, with 300-400 feet of 3/4" 8-plait). And then having a smaller anchor on the stern, like an FX-55 with 15 feet chain and maybe only 200 feet rode with a smaller diameter.

B.O.A.T. (Break Out Another...) without a doubt!

[Don C L]

Maybe your boat’s too big. Ok sorry, just a joke.
Seriously, if you want to go that route I’d look at how to mount the anchor with the rode going into a deckplate stowed and ready to run with the pull of a pin. I’d look into a winch either dedicated to it or a clean way to run back to a halyard winch (kinda doubtful) or windlass. it’s a challenge for a boat with a stern like yours but I bet there is a good way. I probably wouldn’t go for a storm size for the stern. Just the fx55 I think. So, say 30’ of 5/8 chain? How much does that weigh? Still might be too much... not sure
Maybe a remotely inflatable lifting bag on the anchor?
I might patent that idea.....