I believe it keeps the bow into the wind and or waves to help keep from getting sideways and rolling over, a bucket will help pass as a sea anchor. It will also help slow down (mph) when trolling with a larger engine.
In a storm a sea anchor can help a vessel from drifting off course. It will keep the bow in the wind and slow the speed of the vessel.
Drop a sea anchor off the bow.
Deploy a storm anchor (sea anchor) from the bow; something that will slow the boat's drift downwind. Something like a small drogue parachute in the water. The wind will cause the boat to drift, and the waves to rise; the storm anchor will slow down the drift, and keep the boat pointed into the wind. Bow-on is the safest direction for your boat to meet the waves. Otherwise, the wind would tend to push the boat sideways, and you could easily capsize.
weigh down the anchor
weig down the down the anchor
Held fast by or as if by an anchor. An anchor is a heavy object dropped by a boat which embeds itself in the sea floor and thus provides a mooring to which the boat can be secured.
Well in Christianity it is part of a metaphor that life is like the sea and you are a boat, when a storm comes along your love for God can keep you anchored in place ( to be steady and not sink or be broken on rocks).
Anchor
a boat, a storm, an island, sailors who get drunk a lot, ship's doctor
There are vessels designed to to specifically anchor from the stern of the vessel. However if you mean a "fishing boat" as a small recreational or "pleasure" craft like a bass boat, it is almost NEVER recommended to anchor from the transom of a boat. This is especially true if you have any type of current or sea state (even lake or wind waves) as your stern is the lowest part of the boat to the waterline and swamping can happen fast. I have personally seen it at the mouth of the Columbia River bar located in Pacific Northwest. Not to mention you run the risk of fouling your props with the anchor rode.
To secure an anchor for long sea voyage, use the drift anchor or the para-anchor to increase the drag through the sea.To secure an anchor for long sea voyage, use the sea anchor to increase the drag through the water.
If the water and your vessel permit it, you'd be wise to anchor and ride out the storm. If you are in open water, a sea anchor can stabilize your ship bow into the wind, and reduce your leeway.