Anchoring Technique - Three Questions

[psneeld]

A drone with a speargun attachment would be perfect for clearing out the lionfish which tend to live at great depths off Florida. Maybe a stun-gun to kill them off.

Hear they are good eating ....nice thing about Florida Fish and Game laws ....there are no restrictions when dealing with invasive species.

So shoote'm up and cook them up!

 

[Mako]

And when you’re done eating them, the spines make for great toothpicks [emoji3]

 

[psneeld]

And when you’re done eating them, the spines make for great toothpicks [emoji3]

Hand those out to guests who have overstayed their welcome.

 

[SteveK]

Fun is what boating is to me, based on so many TFer inputs, sounds like I am laxidaisical, blowhard and just don't take boating seriously enough.
..................................

Now that is your sign. Care to make it your signature?
Said in good fun BTW

 

[psneeld]

Now that is your sign. Care to make it your signature?
Said in good fun BTW

 

[Slo-Mocean]

I had a large plow set at 8-1 on 3/8 chain back in a shallow but tight protected bay during a Severe weather alert 6 months ago down here in SW florida. I stayed up all night on the bridge as it blew 30-40 per my Anemometer.

At dawn the Krap hit the fan and I started the engines. Between lightning strikes I swear I saw a small tornado come down the entrance canal and the anemometer hit 80 and than we swung hard and broke loose . I powered up and we couldn't see anything for a minute and when it passed we were almost on top of the sailboat previously 500 feet behind us .

Since than I've purchased the biggest Mantis anchor I could find and if I knew something like this weather was approaching again I would pay out the Mantis than clip my big plow 30 ' up the chain from it.

 

[O C Diver]

I had a large plow set at 8-1 on 3/8 chain back in a shallow but tight protected bay during a Severe weather alert 6 months ago down here in SW florida. I stayed up all night on the bridge as it blew 30-40 per my Anemometer.

At dawn the Krap hit the fan and I started the engines. Between lightning strikes I swear I saw a small tornado come down the entrance canal and the anemometer hit 80 and than we swung hard and broke loose . I powered up and we couldn't see anything for a minute and when it passed we were almost on top of the sailboat previously 500 feet behind us .

Since than I've purchased the biggest Mantis anchor I could find and if I knew something like this weather was approaching again I would pay out the Mantis than clip my big plow 30 ' up the chain from it.

While you obviously assumed the anchor broke out based on size, the issue may have been as much based on scope. At 8:1, the chain angle could be about 12 degrees between seabed and chain, causing significant loss of holding. There's no doubt with an 80 knot gust that the chain was straight and the shank was lifted off the seabed. While there's nothing wrong with increasing anchor size, lifting the shank off the seabed reduces holding, as has been mentioned numerous times in this thread.

Ted

 

[Gypsy Island]

While you obviously assumed the anchor broke out based on size, the issue may have been as much based on scope. At 8:1, the chain angle could be about 12 degrees between seabed and chain, causing significant loss of holding. There's no doubt with an 80 knot gust that the chain was straight and the shank was lifted off the seabed. While there's nothing wrong with increasing anchor size, lifting the shank off the seabed reduces holding, as has been mentioned numerous times in this thread.

Ted

Based on a scope of 8:1 the chain angle is 7.18 degrees (angle alpha = INV sin(1/8)). As most anchors have an angle well above 12 degrees there should have been some force left, digging the anchor deeper into the seabed. Maybe the kind of seabed was not holding well in general.

 

[Jeff F]

I found this article useful. https://kb.rocna.com/kb/Scope_vs_catenary

I've been reflecting on my experience with all rope rodes - I traveled 15,000 miles without a windlass, anchoring pretty much every night. Mostly with a claw anchor and 6 feet of chain. The pull on the anchor was always above horizontal, and I never had an issue with 4:1 - 8:1 scope. So while all this talk of chain is fine, we should remember that anchors work fine without it. I remember when the Bruce was first popularized, and one of their big claims was short scope performance.

Rocna explicitly says their anchor is effective between 3:1 and 8:1 without taking catenary sag into effect. I believe that. They also say there is no need for more scope beyond 8:1.

Interesting discussion.

 

[rwidman]

I use a zip tie.

Thanks. I will look into that.

 

[Don L]

10k view and 200+ replies to 3 questions about anchoring

:lol::lol::lol::lol::lol::lol:

 

[Slo-Mocean]

While you obviously assumed the anchor broke out based on size, the issue may have been as much based on scope. At 8:1, the chain angle could be about 12 degrees between seabed and chain, causing significant loss of holding. There's no doubt with an 80 knot gust that the chain was straight and the shank was lifted off the seabed. While there's nothing wrong with increasing anchor size, lifting the shank off the seabed reduces holding, as has been mentioned numerous times in this thread.

Ted

I get what your saying and if I wasn't in such a tight Anchorage I would have had more scope out in the 6 foot depth. I wasn't anticipating a 80 mph gust coming in 90 degrees of the current heading of the vessel.

The high windage of these GHs make them hunt even with the bridle on . We were on a port swing when the gust whipped us hard to starboard and let us get some momentum going on that tack until we ran out of swing than broke loose .

I don't think that plow had the holding power in that silty bay either.

 

[Mambo42]

Before you know it a bunch of TFers will decry that underwater drones are an absoute safety necessity to check the bottom, the anchor digging in and the chain laying the anchor flat.

Kind of funny you say this, because I just bought this one

It was an black friday offer and want to use it mostly for making underwater shots for video purposes. But I guess it will also be helpful with checking a stuck anchor in winter time. Because if there is something I hate doing it is jumping into ice cold water.