What Is the Draft of an Aluminum Shallow-Water Bay Boat?

When anglers talk about getting into “skinny water,” one measurement matters almost immediately: draft. The draft of an aluminum shallow-water bay boat tells you roughly how much water the boat needs beneath it before the hull—or its propulsion system—can contact the bottom.

There is no single draft measurement that applies to every aluminum bay boat. As a broad shopping benchmark, many conventional bay boats draw roughly 10 to 15 inches, while specialized flats boats may target approximately 6 to 10 inches. Hull design, boat weight, engine position, fuel, passengers and fishing gear can all change the real-world number.

That is why serious shallow-water anglers should look beyond one number on a specification sheet.

What Does Boat Draft Mean?

Boat draft is the vertical distance from the waterline to the lowest part of the boat below the surface. In practical terms, it tells you approximately how much water the boat needs to float without the hull or underwater components touching bottom.

On an outboard-powered fishing boat, there can actually be more than one relevant measurement.

With the engine raised, the lowest point may be the bottom of the hull. With the engine lowered, the skeg, propeller or lower unit may extend deeper. Manufacturers may therefore distinguish between engine-up and engine-down draft.

For shallow-water anglers, another distinction matters just as much: static draft versus running draft.

Static Draft

Static draft is the amount of water the boat needs while sitting still.

This is especially important when you are:

• drifting a flat
• fishing from a stationary position
• operating with a trolling motor
• idling through a marsh
• stopping in a shallow creek
• launching or loading near a shallow ramp

Running Draft

Running draft refers to the depth required once a powerboat is moving on plane. As the hull gains hydrodynamic lift, more of it rises out of the water, which can reduce the amount of hull below the surface.

That does not mean it is safe to run unfamiliar water simply because the boat can run shallower on plane. Discover Boating specifically recommends slowing down when the depth is uncertain because striking bottom at speed can damage the boat or leave you stranded.

How Much Water Does a Shallow-Water Bay Boat Need?

A shallow-water bay boat may operate in roughly a foot of water depending on its hull, load and setup, but there is no universal minimum depth. Dedicated flats boats generally draft less, while deeper-V bay boats trade some shallow-water capability for improved performance when crossing open water and chop.

Think of the categories as a spectrum:

The right choice depends less on chasing the smallest possible number and more on where you actually fish.

If reaching back-marsh redfish water is your priority, draft may be near the top of your list. If you have to cross several miles of exposed bay before reaching those fishing grounds, ride quality, freeboard, stability and hull design matter alongside shallow-water capability.

That balance is exactly why bay boats exist.

What Affects the Draft of an Aluminum Bay Boat?

The actual draft of a shallow-water boat changes with hull geometry, total weight, weight distribution and engine position. Published draft figures should be treated as approximate because adding fuel, passengers, batteries, tackle, anchors, coolers and other equipment makes the boat sit lower in the water.

Several factors deserve particular attention.

1. Hull Design

Bottom shape has a major effect on draft.

Flatter hulls generally displace their weight across more surface area and can operate shallower, while greater deadrise can improve the ride in chop but typically requires more water.

Tunnel-hull designs approach the problem differently by creating a channel in the hull near the outboard. This type of design can help provide water flow to an outboard mounted higher for shallow-water operation.

2. Boat Weight

A heavier boat displaces more water.

That does not automatically make a lightweight boat better—weight, hull geometry, beam and construction all work together—but it is one reason aluminum is attractive for many shallow-water applications.

Xpress specifically builds around aluminum construction and describes its 5052 aluminum as part of a lighter, durable boat-building approach. Its construction also incorporates longitudinal ribs, all-aluminum structural components and unibody injected-foam construction. The attached Xpress market analysis likewise identifies 5052 aluminum construction and specialized hull architecture as central parts of the brand’s engineering story.

3. Passengers, Fuel and Gear

Four anglers, a full fuel tank, multiple batteries, tackle, ice, coolers and fishing equipment can produce a noticeably different draft than an unloaded boat.

Even where the weight is positioned matters. Moving several passengers toward the stern can make the stern sit deeper.

For that reason, the most useful shallow-water test is not necessarily an empty boat at the dealership. It is a boat loaded similarly to the way you expect to fish it.

4. Engine and Lower-Unit Position

Remember that the hull may not be the lowest point once the outboard is lowered.

A hydraulic jack plate can vertically raise the outboard, improving lower-unit clearance in shallow water when the boat and propulsion system are properly set up. It does not change the hull’s static draft, but it can make a significant difference in how the propulsion system operates in skinny water.

How Does Xpress Boats Approach Shallow-Water Bay Fishing?

Xpress designed its current Shallow Water Bay Series specifically around shallow-water access without abandoning the ability to navigate open water. The 2026 SW20B and SW22B use a Hydro-Dynamic Hull with a tunnel, all-welded construction, longitudinal ribs and unibody injected-foam construction.

The current lineup includes:

Xpress describes the series as having a nominal draft suited to venturing deep into the marsh. Importantly, the current 2026 specification table does not publish a specific numeric draft measurement for either the SW20B or SW22B. Buyers who need an exact real-world number should therefore verify loaded draft and operating depth with an Xpress dealer rather than assuming a figure based on another boat.

That distinction matters. The attached company research also identifies Shallow Water Bay models as part of Xpress’s broader strategy for marsh and inshore anglers who need shallow access while still potentially crossing open water.

Does a Tunnel Hull Help a Boat Run Shallower?

A tunnel hull can improve shallow-water capability by channeling water toward the outboard, allowing the engine to operate higher than it could on some conventional hull configurations. The benefit depends on the complete boat, motor, propeller, jack-plate height, load and water conditions rather than the tunnel alone.

The Xpress SW20B and SW22B both list a Hydro-Dynamic Hull with Tunnel as standard equipment.

For anglers who spend significant time in marshes, Xpress also lists a Marsh Package that includes a 6-inch Atlas hydraulic jack plate along with other fishing equipment. The combination gives buyers another tool for configuring the propulsion system around shallow-water use.

A jack plate should not be viewed as permission to run blindly over oyster bars, rocks, sandbars or submerged timber. It is a performance and setup tool—not a substitute for knowing the water.

Is an Aluminum Bay Boat Better Than Fiberglass for Shallow Water?

Neither material automatically determines draft. Hull shape, dimensions, total weight and load matter more. Aluminum can provide a weight advantage and is attractive to anglers who expect hard use around shallow-water structure, while fiberglass may offer advantages in weight distribution, finish and certain rough-water hull designs.

For buyers, the better question is:

What combination of shallow access, ride, durability and fishability do I need?

A boat that floats extremely shallow but beats you up during the run across an exposed bay may not be the right boat. Neither is a deep, heavy boat that cannot reach the marsh you fish every weekend.

Shallow-water bay boats are designed to find the middle ground.

How Should You Compare Shallow-Water Bay Boats Before Buying?

Do not shop by advertised draft alone. Ask the dealer to help you evaluate:

1. Static draft with a realistic fishing load
2. Engine-up versus engine-down clearance
3. How the boat behaves coming onto and off plane
4. Tunnel-hull and jack-plate setup
5. Typical passenger and equipment load
6. Stability while anglers move around the deck
7. Ride quality in the open water you regularly cross
8. Trolling-motor and shallow-water anchoring needs

If possible, take a test ride with several passengers aboard.

A few inches on a specification sheet matter. How the entire rig behaves in the water you actually fish matters more.

Choosing the Right Draft for Your Fishing

The ideal draft of an aluminum shallow-water bay boat ultimately depends on the places you want that boat to take you.

An angler working protected marshes may prioritize every possible inch of shallow-water access. Someone fishing large Gulf Coast bays may accept slightly more draft for greater confidence in chop. Many buyers need both.

Xpress approaches that problem with multiple bay-boat platforms rather than treating every inshore angler the same. The Shallow Water Bay Series focuses specifically on thin-water capability, using an all-welded aluminum construction and tunnel-hull design while retaining the center-console layout and fishing features expected from a bay boat.

Before deciding, compare the SW20B and SW22B, think realistically about your normal passenger and gear load, and talk with an Xpress dealer about the water you fish.

The smallest draft number is not always the best boat.

The best shallow-water boat is the one that gets you where you fish—and gets you back comfortably when conditions change.

FAQs

What is a good draft for a shallow-water bay boat?
Many bay-boat designs operate with approximately a foot of static draft, although the exact number varies substantially by model. Dedicated flats boats often target roughly 6–10 inches, while bay boats usually trade some extreme shallow-water capability for better open-water performance.
Can a bay boat run in 12 inches of water?
Some can, depending on their hull, motor setup, load and whether the boat is already on plane. Do not assume that a published draft means a boat can safely start, stop and run in that exact depth. Static draft, running draft and lower-unit clearance can all differ.
What is the difference between static draft and running draft?
Static draft measures how deeply a boat sits while essentially stationary. Running draft is the water depth required once the boat is moving on plane. Planing can lift more of the hull from the water, potentially reducing running draft.
Does adding passengers make a boat draft deeper?
Yes. More passengers, fuel, batteries and gear increase displacement and can make the boat sit lower. Weight distribution matters as well, especially on smaller boats. Published draft figures therefore should be considered approximate rather than guaranteed operating depths.
Does a jack plate reduce boat draft?
A jack plate does not reduce the hull’s static draft. It raises the outboard vertically, which can reduce how far the lower unit extends below the hull and improve shallow-water operating capability when properly configured.
Do tunnel hulls work better in shallow water?
Tunnel hulls can help channel water toward a higher-mounted outboard, which is useful in shallow-water applications. Performance depends on the complete setup—including the hull, engine height, propeller, jack plate, load and water conditions.
What is the draft of the Xpress SW20B or SW22B?
Xpress describes both boats as having a nominal draft designed for shallow-water and marsh use, but its current 2026 SW20B/SW22B specification table does not provide a numeric draft figure. Buyers who need a specific loaded draft should confirm it with an authorized Xpress dealer.
Is a shallow-water bay boat the same as a flats boat?
Not exactly. Flats boats generally prioritize the least possible draft and protected-water fishing. Bay boats typically add more freeboard, capacity and open-water capability. A shallow-water bay boat attempts to bridge those needs by preserving skinny-water access while remaining practical for broader inshore use.