Boat anchor

[rcain1]

Great! All I need is 4 million feet of battleship anchor chain 2.5 miles of line (its called line I think) and lastly a 1200lb plow anchor. I hope OSHA or the Coast Guard don't get me. I would be tons over the weight limit for my boat. Heck, maybe I will just hire a crew to stay on my boat (even in the driveway at home) and insure that have a boat to return to after a dive.

OK, I was making an attemp to be funny. Well it was funny. All thanks for you input and conversation. BUT..... the lakes I am diving on ...... well my boat would hit the other side of the lake before the anchor line grabbed.

I really just wanted to see if some would say something that would spark my mind, not that ya'll didn't. I am a smarter boater now, really!
Thanks

 

[pipedope]

When you go to the chandlery and buy a full spool of cordage it is rope.
When you cut a length off of the rope for a specific purpose it is a line.
When it is in use it is called by the name of the job it is doing.
A line or chain used to attach the anchor is a rode.

There are ways to calculate the size of anchor and rode needed for any given boat but looking in a table and applying fudge factors is faster and easier.

The advantage of a small anchor is easier handling and less weight. Many boats carry a small anchor as a kedge. The kedge is used for maneuvering in a restricted area and can be very handy if the engine fails, there is no wind or the boat is too big to sail in the space available.

As long as it is not too heavy for the boat and crew to handle there is nothing wrong with getting a somewhat bigger anchor. Making the rode too heavy is a bad thing, especially if it is nylon.

Once you have choosen an anchor look up the rated holding power for that anchor in the bottoms conditions you expect to use it. Now double that number. For best results pick nylon line that has this as the rated breaking strength.
Example, if my anchor is rated to hold a maximum of 1800 lbs in the sand bottom. I double that to 3600 lbs and choose a nylon that has a rated break strength of 4000 lbs or slightly higher. I know this sounds like a weak line but we want the line to streach and absorb shocks. This helps keep the anchor in the bottom and helps keep the deck fittings in the boat.

Remember that lots of anchors are lost to chafe on the rode. Rig so that the rode touches as little as possible on the way off of the boat. Anything it does touch needs to be large radius and smooth and if the line can work it is good to use chafing gear to protect the rode.

 

[ScubaToneDog]

Too much chain is not good.....no matter the length, the weight of the chain should not outweigh the anchor. Too long and heavy of a chain will reduce the necessary force to set the anchor....as far as your anchor line, 3-5 times the depth for calm to moderate seas and 6-8 times for strong to heavy. Your creating an angle between you and your anchor...25-35 degrees is optimal. The steeper the angle (45-60) the less likely hood it will stick...The smaller the boat the more scope you will need to keep it set. As far as anchors go, bigger is not always better for small boats either. Get the appropriate size and weight for your boat....see your local boat shop for their recomendation.

Always have a Boat Bunny.....then you never need to worry about your boat getting away....

 

[The Kraken]

rcain1, folks are gonna think you and I are crazy, but that's OK, let 'em.
I have a 30' pontoon boat slipped on Hartwell reservoir on the Georgia/S. Carolina border. One of the reasons I wanted a pontoon is because they make such good diving platforms on large reservoirs such as Hartwell.
One of the problems we have here is that when many of the reservoirs were created there were substantial tracts of trees left standing in tact that would lie below a certain depth when the lake is at normal pool. Needless to say, these old trees reap havoc with conventional anchors. Add to the tree problem the silt that has accumulated for 50 years and you have somewhat of a poor anchorage problem.
I did basically what you mentioned regarding the 5 gallon bucket.
I made a form that is shaped like two pyramids conjoined at the base with a stainless steel rod running through the apexes. Filled the sucker with concrete and let it set up.
No problem penetrating the junk on the bottom and no problem retreiving it due to its pointed shape at the top. I do get one helluva work out pulling it up from 150' sometimes. 45 pounds holds the pontoon in place very well with minimal scope and no chain.
(P.S., if ya make something like this, make sure to take a young beefy diver who likes to show off in front of the girls - I really don't need the workout any more.)

 

[rcain1]

The Kracken,
Thanks for the vote of confidence. All I wanted to hear was there was another human on the planet who has problems with anchoring. If I could I would put down a two-ton metal block down!

Did you make a plywood form or what? I do want something that has an outer film or casing. Concrete and my bow rider will not mix. Did you coat it with anything? I want to make something that fits in the boat and is not to much of a hindrance.

 

[Tiny Bubbles]

Here's a DIY mushroom anchor that I welded up last night.

-Tiny-B.

 

[dannobee]

Good Gawd Man! Wouldn't it have been easier to drill holes and bolt it to the brake drum instead of trying to weld it? I do like it though!

Here's a DIY mushroom anchor that I welded up last night.

-Tiny-B.

I second the more chain the better (well, within reason, of course).

Proper setting of the anchor, lots of chain and double checking on the dive has always worked for me.

 

[Cacia]

Very informative thread! Now, if I can find the right guys to trail that anchor line...

I am told throwing the anchor even in deep sea is an important safety ploy if you have engine troubles. Slows your ride out to open ocean down? I worry a bit when there is no one on the boat during a dive... a good anchor job imperative for peace of mind. I learned trying to "better set" an anchor in rough ocean can be risky.

I would think you guys could be targets for missing persons investigations with all those homemade anchors.

 

[Tiny Bubbles]

Good Gawd Man! Wouldn't it have been easier to drill holes and bolt it to the brake drum instead of trying to weld it?......

I hadn't even thought of drilling and bolting... I bet it would have been easier! I was going to use a piece of rebar for the shank, but when I rummaged through my junk pile I couldn't find any. I came out of the junk pile with a piece of flat steel instead, and never stopped to consider other ways of attaching it to the drum.

-Ray

 

[NadMat]

Very informative thread! Now, if I can find the right guys to trail that anchor line...

I am told throwing the anchor even in deep sea is an important safety ploy if you have engine troubles. Slows your ride out to open ocean down? I worry a bit when there is no one on the boat during a dive... a good anchor job imperative for peace of mind. I learned trying to "better set" an anchor in rough ocean can be risky.

I would think you guys could be targets for missing persons investigations with all those homemade anchors.

Not everybody is so lucky as to be anchoring off of beautiful pacific islands Catherine

Things are a little bit more forgiving in our landlocked lakes here in central Texas. And in some local lakes, the homade anchors work as well or better than the standard anchors, as are usually designed to work specifically for those local conditions.