anchoring an empty dive boat

[Chuck Tribolet]

....

I'll stick with my 5 pound Danforth. I can usually anchor in sand where
it just burries itself. The harder it blows, the deeper it goes. And it
snags rocks pretty well too.....QUOTE]

That is an awfully light anchor for the ocean. It is of course the "grabbing" of the flukes but there certainly is a weight element to be considered.

--Matt

No, there isn't a weight element to be considered. It just buries itself, and if it's been
blowing, it can be a real bear to pull it out from directly above. I boat out of Monterey,
on the end of the longest fetch on earth. I've got 500 days on the water here,
and unless it gets fouled in the chain, it just works. A little resistance on the line
as it goes down keeps the chain above the Danforth where it belongs. I used to have
an 18 pounds anchor and it would just skate across the sand. Want it? Come get it.

 

[endorfin]

I dive off a 31 foot boat and leave it unattended about 70% of the time. I'm usually in 50' to 80 feet of water. For peace of mind I check the anchor when we go down, and I run 200' of 1/4 inch chain and 100' rode with a 25# plow type anchor (Delta). Instead of going heavier on the anchor I went with more chain and a good windlass. The advantqage is I can go with a shorter scope, and the weight of the chain keeps the boat over the anchor (less wandering). It takes a lot to lift 50' of chain off the bottom before it even starts to pull on the anchor. I've anchored countless times over the last 3 years with this set up, and haven't drug anchor once even with as little as 3 to 1 scope.!

 

[SubMariner]

That's stilll way high, at least for some anchor types.

Going through the West Marine catalog, I get the following anchor weights for a 24'
boat:

8, 6, 9, 4, 6, 8.5, 5 pounds for Danforth type anchors (p 706-707)
18, 33, 10, 30, 16.5, 14, 25, 16.5 for plow type anchors (p 708-709)

West has an incentive to sell you a bigger anchor, not smaller (more profit),
so if anything, these numbers will be on the high side.

I'll stick with my 5 pound Danforth. I can usually anchor in sand where
it just burries itself. The harder it blows, the deeper it goes. And it
snags rocks pretty well too.

No offense, but a 5# anchor is a toy; for anything more than a row boat it's asking for trouble. Add in anything resembling big wind/waves and it won't hold.

Hold is a combination of weight, scope/rode, and anchor configuration. Relying on only or two components is not prudent.

JMHO, of course.

 

[Chuck Tribolet]

No offense, but a 5# anchor is a toy; for anything more than a row boat it's asking for trouble. Add in anything resembling big wind/waves and it won't hold.

Hold is a combination of weight, scope/rode, and anchor configuration. Relying on only or two components is not prudent.

JMHO, of course.

Poppycock. Danforths hold by digging in, not by weight. I've had it in reasonably big
waves (10' swells) and winds (30 knots). It works.

Danforth specs it for boats to 31' in 20 knot winds. Danforth is not motivated to over
spec their anchors. If the they did, they'd be exposed to liability suits and be missing
an opportunity to sell you a bigger anchor. I have a 17' boat, 5 pound Danforth,
13' SS chain, 250' 3/8" line. I have plenty of excess anchoring capacity.

 

[Uncle Pug]

No offense, but a 5# anchor is a toy

It is all relative.

Chuck is successfully anchoring a light 17' Montauk with little windage using a 5# anchor. I use a 33# Bruce anchor to hold a 20,000+ pound trawler with considerable windage. His anchor weighs *more*, relatively speaking, than mine.

As Chuck mentioned in a previous post, when using a *digging anchor* adding chain is more effective than adding anchor weight. The weight of the chain adds cantenary and causes the anchor to dig in deeper.

BTW: My 60' of chain weighs more than twice what my Bruce weighs... and the 600' of rode weighs more than that.

 

[Bill51]

The one place a little more heft to a Danforth anchor pays off is when you have a soft silt or sand bottom with hard mud or sand 6-12” below it. I’ve seen relatively large aluminum Fortress anchors flatten out and start skipping over the hard bottom where a heavier Danforth gets a better bite in the hard bottom – mo matter how much chain or scope you have.

When you dive down to the anchor you can usually tell this is happening (assuming you backed down on the anchor) if you see a larger mound over the top of the anchor than usual for the depth the anchor has sunk in.

 

[CaptAdam]

A prudent sailor will never leave his boat with out someone standing anchor watch on any size boat.

 

[Uncle Pug]

I'm glad I'm not a sailor or a prude.

We leave our trawler anchored all the time and take the whaler to town or out Orca watching. Left it anchored in one spot for a couple of weeks and all that happened was the anchor dug in deeper and deeper and deeper.

 

[jchaplain]

A prudent sailor will never leave his boat with out someone standing anchor watch on any size boat.

Sounds same as "A safe diver will NEVER dive solo."

Same argument...different day.... :shakehead

John C.

 

[jchaplain]

I'm glad I'm not a sailor or a prude.

We leave our trawler anchored all the time and take the whaler to town or out Orca watching. Left it anchored in one spot for a couple of weeks and all that happened was the anchor dug in deeper and deeper and deeper.

My final solution to the issue....I'm using a fairly small Danforth....8 lbs I think...small for a 24 foot boat, but it makes raising the anchor easy. I'm using a lot of chain rode.

Then at the bottom doing an anchor check and then looping an additional rope and chain loop over a nearby large rock to be positively securely anchored.

Then diving with a reel since vis in Boston is so bad to be sure to return to the anchor. Works fine and keeps it very safe.

John C.