I''ve never anchored my boat, but I am pretty sure the size and type of anchor depends on what type of bottom you are anchoring in ( sand, mud, rocky, etc ). Also the ratio of depth to feet of anchor rode. Should be 5 to 7 ft of rode for every foot of depth.
What type of water are you in? Lake, river, do you have a current, what kind of bottom do you have mud, sand, rocky, stumps? Let us know that and then we can probably try to match the type of anchor to you situation.
For 40' depth you need 280' of anchor line out to get the recommended 7 to 1 slope. How much line do you let out. If not very much, that's your anchoring problem.
wvcatfish,
To find the right anchor, you need to know what the bottom is like where you fish most of the time. I fish in a mud bottom lake most of the time and I use a 25 lb Richter (www.westmarine.com) anchor and it works great for me with about 100' of rope at most.
You are going to need at least 150' of anchor rope for that depth of water. I like 3/8 double braided nlyon for my anchor lines. Also put a 6' length of 5/16 chain between the anchor and line. I would suggest a 28# navy anchor.
We have had tremendous luck with a box anchor - which holds very well, requires much less scope that other types, and also continues to hold even if the wind reverses (which is does frequently on our lake). I have a 22-foot pontoon and bought the 19-lb "small" box anchor. I attached 4-feet of chain even though the documentation says that chain is not needed. Even in a stiff breeze, I never need more than 3:1 scope.
Ii is generally accepted in the boating community that you need to let out 7' of line for each foot of depth you are anchoring in. That way, you are not depending on just the weight of the anchor, but getting the benefit of a more lateral force which lets the anchor grab the bottom as it was designed to do. You oftem can get by. With less slope depending upon you anchor, the bottom type, your boat, etc.
Several people mentioned chain. This serves several purposes. One, it keeps the achor forces more lateral, less up, absorbing a bit of the boat movement. Second, it is protection from things (rocks, etc) cutting your anchor line.
I too used the "small" box achor for my 22 1/2' pontoon. I have never had a problem with it letting go of the bottom. My lake is mostly soft bottomed. I have no chain in the rode and typically use only about a 3:1 ratio for anchor line. This anchor really seems to work well.
I guess I have to agree. lol. The advantage of a pontoon is that we have no bow pulpit and I keep the anchor under one of the foward seats. It just wouldn't have worked with our last boat - a 30-foot double-cabin cruiser.
You are right - they sure aren't cheap. Our pontoon was delivered with a Hooker-type fluke anchor and I had a tough time getting it to set on our lake (mostly mud bottom). Don't understand exactly why it was tough since I never had an issue in earlier boats when we lived on the Chesapeake Bay.
Anyhow, I read good reviews about the box anchor, bit the bullet and spent the extra money, and have never had an issue since then. Although the documentation says that chain isn't required, I had a nice 4-foot section of pastic-coated chain and decided to use it anyway.
In addition to setting easily, I love the way it will turn over and reset itself when the wind reverses.
I'm sure I may have found other anchor styles that solved my original issue, but this is the one I settled on.
