How To Know How Deep To Set Your Float – 2 Easy Ways

Knowing how deep to set your float is a critical part of good float fishing
This pool starts out at 4 feet deep for 30 feet, then has a high 2 foot high spot and then drops into 6 feet of water, but it also has a trench on the far side that is close to 8 feet deep where this client hooked his fish. Without knowing how deep to set his hook he would have never caught this fish.

Knowing how deep to set your float is a critical part of good float fishing and if you do this well you will catch a lot more trout, steelhead, and salmon in the rivers that you fish. But how do you know how deep to set your float? In this article, I will answer this important question but be warned now that these are advanced techniques that I use as a guide that have helped put thousands of steelhead in the net for my clients.

You want to set the depth of your float so that the bait is 8 to 16 inches off the bottom of the river because that puts the bait right in the fish’s face. The closer the bait is to the fish the more likely it will eat it. You can use your float and bait to detect the bottom.

As a guide, I set or adjust my client’s floats for them because I know exactly how deep each spot is. But many anglers don’t know how deep the spot they are fishing actually is and they often fish too high or too low and they don’t make the necessary adjustments to their float to get it down to the fish. This means they are missing fish.

Setting your float too deep from the start might mean you will be snagging on the bottom and you may lose your hook and bait on the first cast. The other problem is that few fish will feed down.

A recent study indicated that fish in a river tend to only feed down 13% of the time. The other 87% of the time those fish are feeding on food straight that is eye level or above and beside them. This is another reason why you need to set your float at about 12 inches off the bottom.

Know How Deep To Set Your Float By Finding The Bottom

I tell my clients that when they get to a new spot and they can’t see the bottom or can’t visually determine the depth of the spot, their first or primary goal is to find the bottom, then start focusing on catching a fish.

If they are lucky, they will catch fish while they are trying to find the bottom.

Finding the bottom is a great way to set your float for the right depth of the spot or the line that you are about to drift your float down. Once your find the bottom you simply make your leader below the float shorter.

I use a few methods for finding the bottom because finding the bottom is actually harder than you think for a few reasons which I will discuss below.

I will also discuss exactly how I find the bottom below.

The River Bottom Is Not Always Flat

One of the reasons that finding the bottom is difficult is that the bottom of a spot that you are fishing might not be the same depth everywhere through the entire spot.

The top of the pool could be deeper than the bottom, or the far bank could be deeper than the close bank or maybe there are some high spots or some deep spots. I will discuss how to figure all of this out.

If you are in a spot that is mostly 5 feet deep and you set your float so your bait is 1 foot off the bottom, you will catch some fish, but there could be a spot in the middle, or near the back of the pool that has a 6 foot wide by 10 foot long deep trench that is 9 feet deep and that could be where 80% of the fish in that pool are holding.

This means that if you set your float 1 foot off the bottom in 5 feet of water, your bait could be 4 feet out of the strike zone for 80% of the fish in that pool.

One side of the river could also be shallower than the other side of the river so where you set your float for halfway across the river might not be good for the other half of the river closer to the far bank, or vice versa.

I map out the bottom of all the spots that I guide so that my clients don’t miss any fish and this is one of the reasons why some years I will hook over 500 steelhead.

My clients will often see me set the float depth 2 or 3 times in the same spot and I do this because I want to make sure I get their bait in the strike zone of fish that are sitting in holes or trenches that I know are deeper.

Use The Right Bait For Finding The Bottom

Some baits are more buoyant than others and baits like a plastic worm that floats are not a good bait for finding the bottom.

Using a heavier bait like a tungsten weight fly, or a glass bead which are both very heavy are the best baits to start with to help you find the bottom. Your goal is to simply find out how deep your float needs to be before those heavy baits start dragging the bottom or hooking fish.

If I start hooking fish before I hit the bottom I will keep fishing that depth because chances are it’s just above the bottom anyways.

If my float starts catching bottom or tilting hard downriver I will make it 12 inches shorter.

Setting your float by usingg this drop shot rig
This drop shot float rig is a great rig for helping you find the bottom so you know how deep to set your float.

You can also use a weight closer to your bait to make it heavier and to help you locate the bottom, or you can use my drop-shotting rig like the one in this diagram which puts your weights below the bait.

This is my number one rig for finding and mapping out the bottom.

With the Drop shot rig, your weight will gab the bottom which lets you know that you hit bottom and often you will lose some weight if it gets snagged up, but you lose almost no hooks or baits.

Some lighter baits will simply drift or lightly drag across the bottom making it hard to detect the bottom with your float. But the weight will stick and grab the bottom making it easier to detect the bottom.

Mapping Out The Bottom – Why It’s Important

An added bonus to mapping out the bottom and knowing where these shallow and deeps spots are is that there are times of the year or even times of the day when fish will hold in the deeper spots.

This is an exact bottom map of one of my favorite steelhead pools.
This is an exact river bottom map of one of my favorite steelhead pools. During low light hours or when the fish are moving I catch all the fish at the top of the pool near the rapids but at other times there are no fish there.

If all the fish are holding in the part of the pool that is very deep because it’s cold, or because the sun is high and bright and they don’t want to be in the shallow water if you don’t know where that deep spot is you will end up missing fish.

In the picture above I show you an exact river bottom map of a favorite steelhead pool on my guiding run.

During low light hours or when the fish are moving in early fall, I will catch almost all my steelhead at the top of the pool near the rapids which is where they will stop for a couple minutes to rest before they shoot up through the rapids to the next pool. This is a great spot early morning and just before dark when they are ready to start moving up the river.

During mid-day when the sun is high and the fish stop moving and they are less active I stop catching fish at the top of the pool and I will catch them all in the middle of the pool where the current is slower.

In late fall or wintertime when the water is ice cold, I only catch fish in the deepest part of the pool where they are holding. This is why mapping this one particular pool has put hundreds of steelhead on the line for my clients. On that same stretch of river, I have many other pools that go from shallow to deep or have trenched that the fish tuck into.

An angler that doesn’t have this pool mapped out and doesn’t know there are shallow and deep spots will hit bottom in the middle of the pool where it is shallowest and then set their float at 3 to 4 feet deep and that means they will miss all those fish sitting 9 feet down.

I see this happen all the time, anglers bump or locate the bottom, set their float to that level, and then never touch it again, and they miss a lot of fish because of this.

Fish during the winter or fish holding in very deep water are often less active and won’t move very far for a bait which is why you need to find these deep spots and map out the bottom of the pool.

Mapping the bottom has allowed me to catch 10 times more fish, and allows me to stay on fish under all conditions and at all times of the year.

How Do You Set Your Float

The first thing to do when setting your float is to look at the spot you are about to fish and try to determine how deep it is by what you can see.

If you can’t see the bottom just guess based on what you can see.

At the edge of the bank, you might be able to see the bottom out into the river until it looks to be about 3 feet deep and then you lose sight of the bottom. Maybe you can see the bottom at 4 or 5 feet deep before you lose sight of the bottom. This is the depth that I would start with.

If I lose sight of the bottom at 3 feet deep I set my float to 3 feet deep and make a cast in close and see if I either hook a fish or a hook bottom. If nothing happens I make it 1 foot deeper and cast into the same spot and see what happens.

I also use just the angle of my float to help detect the bottom because sometimes you will be on the bottom but the float won’t pull under. When searching for the bottom I will hold the float back just enough so that it stands perfectly straight up, if it keeps hard tilting downriver I’m hitting or dragging the bottom.

If I don’t hit bottom on my first couple of drifts, I will keep making my float deeper until I start hitting the bottom. Once I hit bottom I will make my leader 6 to 12 inches shallower or shorter because I know fish feed up and I will make a couple of casts and hope for a fish.

Then I will move my float out 1-foot further and see what happens in that line. If I don’t hit the bottom there, I will make it 1 foot deeper and I will repeat until I hit the bottom there and then move it one foot further again and repeat the process.

I will repeat this method all the way across the entire spot because it might be 4 feet deep at 10 feet out from the edge of the bank that you are standing on, but it might be 8 feet deep 15 feet further out.

Cross Section of a river
One side of the river could be deeper than the other side. If you are standing on the left bank and set your float based on the 4 foot depth you will be too shallow once you get closer to the other side.

I fish or drift my float in lines from the top of the pool to the bottom of the pool and I find the bottom with every line until I know where the bottom is. This is how I map out the bottom of the pool.

Once I have mapped out the bottom of the river, I memorize it so I know how deep I need to be each and every time I fish that same spot.

The key is, once you start hitting the bottom, shorten up your leader by 12 inches so you are not dragging the bottom.

When I move to the next spot I repeat the process.

If you want to know how I teach my clients to fish in lines or how to cover the water effectively, I suggest reading my article Effectively Covering The Water When Float Fishing.

How Do You Find The Holes?

How to find deep spot in the river
Finding the deep spots and fish in what I call the trenches can be the key to catching more fish.

Finding the holes can be difficult but it’s not impossible.

I talked about dragging a heavy bait or some weights across the bottom to locate the bottom. Once I find the bottom I will make my leader 12 inches shallower and make a couple of good clean drifts at the right depth. Good clean drift mean having the proper angler and speed.

Speed control is the most critical fundamental of good float fishing and you can see more about that on my page Controlling Your Speed For More Fish When Float Fishing.

To find out if there is a hole or trench, after a couple of good drifts and before I move my cast 1 foot further out I will make it deeper by 1 or 2 feet and purposely try to drag the bottom while trying to hold my float as straight up and vertical as possible.

What I’m looking for is, if the float keeps wanting to hard tilt downriver but them all of a sudden stands straight up and doesn’t want to hard tilt down, it likely means it just got deeper there and I found a hole.

Sometimes a hole or trench on the bottom might only be a small 8-foot by 3-foot trench that is 3 or 4 feet deeper than the rest of the pool and many fish will hold there.

Sometimes, the pool could be shallow at the top but then deeper near the back of the pool. If you are hitting lots of bottom in the first 30 feet and set your float at 3 feet to fish that first 30 feet but the back half of the pool is 9 feet deep you will miss a lot of fish at the back of the pool.

Once I find a hole I will remember exactly where my float went from tilted downriver to standing up because that is the start of the hole and I will make repeated casts right where the hole starts and will make it deeper and deeper until I hit the bottom of that hole.

I will also remember where the float start to drag again because that is the end of the hole. The hole might be 5 feet long or 35 feet long.

I repeat all these steps and drag the bottom from one bank to the other and from the top of the pool to the bottom of the pool until I have completely mapped out this pool, and then I move to the next one and do it again.

Controlling your depth during the presentation is one of the 4 fundamentals of float fishing that I teach when guiding. It’s important to know and do all 4 fundamentals well if you really want to catch more fish when float fishing.

If you are not sure what these 4 fundamentals are check out my page Centerpin Fishing For Beginners: 20 Steps From A Top Guide.

If you know someone that struggles to catch fish when float fishing, be a good friend and share this website with them too.

Got A Question About How Deep To Set Your Float

The two best methods for finding the bottom are to use the drop shot rig or use the drag method with a heavy bait or fly. But if you have a question, comment, or tip regarding how deep to set your float let me and other readers know in the comments section below.

Tight Lines


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