Anchoring By The Stern

[thinwater]

Why would Tom Neale--who works for Boat US, an insurance company--NOT give a fair hearing to something that would reduce losses? The dollars say he would.

A64. Actually, a drogue off the bow (actually about 20 feet down the chain) is more effective. You want to increase drag forward, not aft. Tom Neale hinted at this, suggesting a very long lazy loop on the snubber.

Yawing does increase certain forces, but it does not increase peak forces as a rule. Because the boat is off at an angle, the wave does not cause the boat to snatch up tight against the chain. Yup, I've had a load cell on this. Still, it is a bad thing for other reasons.

Not all boats horse around. Mine does not. It may have other flaws, just not that one.

[a64pilot]

Given a very high wind velocity and I bet there will be some water movement, maybe not in an enclosed bay, however the drogue would resist any movement, I believe it would reduce sailing at anchor

[Dockhead]

I don't think there is anything controversial about it. Obviously, a boat is going to be more stable when the center of air pressure is behind the center of lateral resistance in the water. We've all experienced boats yawing at anchor. Jordan explained the principles many years ago.

The problem is that boats meet waves in storm conditions much better from the bow. Also, no one is set up to anchor seriously from the stern (I'm not talking about little day sailers). Therefore, we anchor from the bow.

In a storm, you can damp off the "dynamic instability" by using a spring line to lie and some angle to the wind.

I don't think this is any big deal, nor anything which hasn't been thought about long ago by many of us.

[jsc7]

Well, there is a certain amount of truth to it, but if you anchor to the stern, then waves will wash over the stern.

Also, it would be expensive to configure an anchoring system for a boat, just so it can be more firmly anchored during a once-in-a-lifetime event.

A more sensible course of action would be to use two anchors on the bow with bridles in the event of a hurricane.

[weavis]

A number of posts have been removed. CF members can now discuss freely without fear of interruption or contentiousness.

[Cheechako]

Originally Posted by CaptTom

Does anyone actually DO this? What are the pitfalls?

I'm not questioning the overall theory, for certain hull designs. What I'm curious about is whether there are other issues. Like shipping more water into the cockpit over the stern, or the fact that just about everything on a boat is designed to shed water aft - from hatches and ports to the little clamshells that cover wiring penetrations.

No way am I anchoring by the stern for any purpose. Been there, tried that. Wet , noisy and for all the reasons noted above too.

[contrail]

Originally Posted by CaptTom

Does anyone actually DO this? What are the pitfalls?

I'm not questioning the overall theory, for certain hull designs. What I'm curious about is whether there are other issues. Like shipping more water into the cockpit over the stern, or the fact that just about everything on a boat is designed to shed water aft - from hatches and ports to the little clamshells that cover wiring penetrations.

Personally, I don't care to anchor by the stern, but I have spent a considerable time in Puerto Rico, a very boating oriented place, and almost everyone there does just that, in boats large and small, including large sportsfishers. They also love to raft, which I am not particularly fond of. While i have no idea about their storm anchoring, the above is quite the norm in tradewind and Christmas wind conditions, in other words winds of 15 to 30 knots, with higher gusts. Only rarely, if ever, do I see them re-orient the boats or break up a raft due to weather.

When I first moved to the BVI, I looked at these two practices with some know it all amusement, but after watching for years and years, I can say that it's the normal practice for Puerto Rican boaters, and they do it very, very, well. Their raft ups are also well coordinated and organized. Respect!

So ,yes, people do this.

[weavis]

Originally Posted by contrail

but after watching for years and years, I can say that it's the normal practice for Puerto Rican boaters, and they do it very, very, well. Their raft ups are also well coordinated and organized. Respect!

So ,yes, people do this.

What hull shape is the Puerto Rican boats?

[a64pilot]

Last Hurricane that came through I noticed the larger Air Force boats from Tyndall were both tied to their Hurricane moorings by the stern.
These are not small boats, I'd guess 80' or so.

[Suijin]

First of all, the Ocean Brake website is just about the worst I've ever seen. A shame, as they would probably be doing a lot better overall as a company with more effective representation.

A boat is designed to face into the wind and waves. Yes, their point about dynamic instability is a good one, but to advocate for a tactic that puts the boat at a serious disadvantage in other ways strikes me as generally wrong headed when there are other tactics that can be pursued to maximize stability. Multiple anchors, pellets, riding sail, etc.

It's almost as though they're throwing out this idea as some sort of tangential rational for the Jordan Series drogue design approach.

Fortunately, my boat is a true cutter rig with the mast almost at dead midships. She's very well behaved at anchor in strong winds. With a canoe stern she might in fact fare better than most boats anchored by the stern, but I would be very concerned about max loading if she's pitching stern-first into oncoming waves.

[UNCIVILIZED]

Yep, when I read the 1st post in the thread, the thought that went through my mind was to use a drogue on the mothership (aft, or forward) in order to minimize yawing, as well as the violence of it. Or barring that, dropping an anchor under foot. The latter practice being quite an old one. Though no longer common, mostly due to training curriculum, or lack there of.

[contrail]

Originally Posted by weavis

What hull shape is the Puerto Rican boats?

Normal shapes....most, but not all are powerboats. Anything from small console boats with outboards all the way up to large cruisers and sportsfishermen, say 50 feet? So, one end pointed and the other end flat. AFt cockpit, mostly, many with swim platform and maybe a door.

Cheers,
tim

[weavis]

Originally Posted by contrail

Normal shapes....most, but not all are powerboats. Anything from small console boats with outboards all the way up to large cruisers and sportsfishermen, say 50 feet? So, one end pointed and the other end flat. AFt cockpit, mostly, many with swim platform and maybe a door.

Cheers,
tim

Thanks Tim

[surf_sail]

Originally Posted by a64pilot

I am going to go out on a limb and say that the instability in fig 1 can be tamed by a drogue out the stern.

Putting a drogue out seems like a much better idea! If dynamic instability is such a big problem (and my two aerospace degrees tell me it likely is) I'm surprised putting a drogue out in severe condition anchoring isn't common practice... would be great to know if anyone has tested this.

[Don C L]

I have little doubt that anchoring by the stern will make a well behaved boat. I just would never be comfortable with the rudder now pushed out there on the bow pointing the wrong direction on a rough day. If you are sure the rudder is safe from being slammed back, perhaps using a rudder lock, and you don't mind the slapping and the splashes and spray into the cockpit then I guess its ok. Not my first choice. And this is coming from someone who regularly anchors bow and stern, in fairly small protected coves, and occasionally my stern will face a brisk night wind but not an onslaught of swell too. If I do by some chance, I wake up move the bow line to the stern and vice versa and go back to bed. My stern anchor is big enough to act as bow when needed. And yes you have to lay out a boat length of both anchor rodes on deck to do that, but it's not that hard.