5 Signs Your Boat Slip Needs Dredging

Sediment accumulation is one of the most overlooked forms of dock and marina deterioration. Unlike a rotting piling, which is obviously a problem once visible, shoaling in a boat slip happens gradually — and the consequences tend to arrive all at once when a boat props up on the bottom or suffers prop damage on a previously clear bottom. These five signs tell you it is time to call for a dredging assessment.

1. Your Boat Sits on the Bottom at Low Tide

This is the most clear-cut sign — if your boat is resting on the bottom of the slip at low tide, you have a shoaling problem that needs immediate attention. The risk is not just inconvenience. A boat that grounds at low tide and floats off on the rising tide is subjected to repeated hull stress that can cause damage to the keel, running gear, and hull structure over time. In tidal environments, repeated grounding events are not acceptable. If your boat is touching the bottom at any point in the tidal cycle, dredging is not optional.

2. Propeller Damage or Excessive Prop Wash

Prop strikes against the bottom are one of the leading causes of propeller damage on the Gulf Coast — and they happen in water that used to be clear. If you are experiencing unexplained propeller dings or bends, or if your engine is stirring up unusually thick muddy water when entering or leaving the slip, sediment has accumulated to the point where it is in the path of your running gear. Prop strikes from shoaling tend to get worse fast once they start, because disturbed sediment re-settles and the soft bottom develops pressure points where the prop routinely passes.

3. Difficulty Maneuvering in the Slip

A slip that used to accommodate your boat with comfortable clearance now feels tight. You are having to time your entries and exits with the tide. You are using higher throttle than you used to in order to push through the slip, because the hull is experiencing resistance against a rising mud bottom. These are behavioral signs that sediment has significantly reduced the usable draft in the slip. The problem is especially common after major storm events, when storm surge can deposit several inches of sediment in a single weather event.

4. Visible Sediment at Low Tide

If you can see the bottom of your slip at low tide — or nearly see it — and it is significantly higher than it was when you first used the slip, sediment accumulation is the cause. Gulf Coast slip bottoms in river-influenced and estuarine environments can accumulate several inches of material per year in high-sedimentation areas. Over a decade, a slip that had 6 feet of depth at mean low water may have only 3–4 feet, dramatically limiting the draft of boats that can safely use it.

The material that accumulates is not always visible sand. In many Gulf Coast environments, the sediment is a soft, dark organic muck — a mix of fine silt, clay, and decomposed organic matter — that feels spongy underfoot and does not always look like what people think of as "sediment." If the bottom of your slip is soft, dark, and rising, it needs to come out.

5. Water Discoloration Around Your Slip

A slip with significant soft sediment accumulation will show persistent water discoloration — typically a milky brown or greenish-brown color — around the hull and in the slip interior, especially when there is boat traffic or tidal current. This suspended sediment can also affect hull condition and cooling water intakes. The fine organic sediment that characterizes many Gulf Coast slips is also corrosive to hull paint and can accelerate marine growth on the hull bottom.

What Causes Boat Slip Shoaling?

On the Gulf Coast, the primary sources of slip sediment are river-borne suspended particles (most significant in Louisiana and the western Gulf), tidal transport of fine marine sediments into sheltered areas, biological material (decomposing plant matter, algae, and marine organisms that settle to the bottom), and storm deposits from surge events. The combination of warm water, abundant river drainage, and productive marine ecosystems makes Gulf Coast slips among the most active shoaling environments in the country.

When to Schedule Dredging

If you are experiencing any of the five signs above, a dredging assessment should happen as soon as possible — the conditions will not improve on their own. If you are not yet seeing signs but have not dredged in 7–10 years, a depth survey will tell you where you stand and allow you to plan proactively rather than reactively.

Deep South Marine Restoration provides boat slip dredging assessments and services throughout the Gulf Coast, including Louisiana, Mississippi, Alabama, Florida, and Texas. Free site assessments are available — call or text 985-200-2225 to schedule yours.