Towing a Wide or Heavy Boat: Width Limits, Oversize Permits and When to Hire a Hauler

Measure at the widest point of the whole load, not just the trailer frame:

• The boat's beam including rub rails, rails, fenders hung over the side and anything bolted on
• Trailer fenders, guide-ons and lights
• Mirrors and side-mounted gear on the boat

Write down the number in feet and inches. If it's anywhere near 8'6", measure twice with a helper holding the tape level across the widest spot.

• Height: measure from the ground to the highest point with the boat on the trailer: windshield, hardtop, T-top, radar arch, antennas, tower or mast. Lowering what folds down counts. BoatUS points out that larger boats often exceed maximum height as well as width, and it's the owner's job to remove anything too tall.
• Length: measure the trailer including the tongue, and the full length of vehicle plus trailer, including any overhang of the bow, swim platform, motor or mast.

Compare with your state's limits and every state on your route.

Discover Boating recommends weighing the boat and trailer at a truck-stop scale with a full fuel tank and your normal gear, then the whole rig for the combined weight. Check that:

• The trailer and tires are rated for the load (capacity plate).
• The tow vehicle is rated for it. For a safety margin, Discover Boating suggests not exceeding 80 percent of the vehicle's maximum towing weight.
• You meet each state's brake rules for that weight.

Over-weight loads can need permits too; Texas, for example, issues oversize/overweight permits for vehicles or loads that exceed its legal size and weight limits.

Discover Boating's advice is to research the laws for your state and any other state you'll tow through, starting with each state's department of transportation. For each state, find:

• The legal width, height, length and weight limits
• Whether you need a permit, and which kind (single trip or annual)
• Required flags, signs and lights
• Travel days and hours
• Escort requirements and at what dimensions they start

Texas's motor vehicle department, for example, says any vehicle or load over its legal size or weight limits must have an oversize/overweight permit, and an authorized route when applicable, before it travels on Texas public roads, and you must know the exact dimensions and weight to apply. Most states work the same way through an online permit system.

Have ready:

• Exact width, height, length and weight
• Tow vehicle and trailer plate numbers and VINs
• Origin, destination and travel dates
• Your proposed route

Apply early. Some states issue simple wide-load permits quickly, but loads that need route surveys or escorts can take longer.

If you tow the same wide boat to the lake all season, ask about longer-term permits. Minnesota's transportation department, for example, issues annual, seasonal and single-trip oversize/overweight permits through an online system, and notes that a permit may include specific route instructions to avoid low bridges, weight limits and construction. Other states have their own options.

Know which agency issues the permit. A state DOT's permit covers state highways; county and city roads can need their own permission. California's Caltrans, for example, says it issues special permits for oversize loads on highways under its jurisdiction, offers single-trip, annual and repetitive permits online, and separates loads by width and height bands, with some routes off-limits to certain permit loads. If your trip starts or ends on local roads (a home driveway, a marina street), call the county or city too.

When the permit arrives, read every condition. Florida's rule, for example, says the vehicle and load must match the configuration on the permit, trip permits are valid only for the routes listed, and an electronic copy is acceptable if it's readily available and legible. Carry the permit (printed or on your phone) for every state.

Requirements depend on the state and on how far over the limit you are. Florida's rule shows the typical pieces:

• Flags: red or fluorescent orange, at least 18 by 18 inches, displayed at the corners and the extreme ends of the load so they wave freely.
• Signs: a yellow "OVERSIZE LOAD" banner with black letters, front and rear, on wider loads.
• Warning lights: rotating, strobe or flashing amber lights once the load passes certain dimensions (Florida starts this over 10 feet wide).

Separately from permits, BoatUS notes that trailers wider than 80 inches need three red identification lamps across the rear. Make sure the trailer's lights are all working before you leave.

Discover Boating warns that some states keep wide loads off the road at certain times, such as weekends. In Florida's rule, unless the permit says otherwise, permitted movements are prohibited on weekends and holidays, the wider classes are limited to daytime hours, and no travel is allowed when visibility drops below 1,000 feet; a load already underway in bad weather must get off the road and wait. Plan fuel stops and overnight stays so you're never caught on the road outside your allowed hours.

Above certain widths, lengths or heights, states require one or more escort (pilot) vehicles. Florida's rule shows what that involves: escort drivers who meet training requirements, escort vehicles with signs, flags and amber lights, radio contact with the load, and rules about where the escort drives on two-lane and divided highways. For a private owner, needing escorts is usually the point where hiring a professional transporter becomes the practical answer (step 12).

• Check bridge heights, posted weight limits, tunnels, tolls and construction on the permit route.
• Avoid narrow, winding two-lane roads where possible.
• Don't leave the permitted route. If a detour forces you off it, contact the permit office.
• Plan where you'll fuel: a wide rig needs a big station with room to pull through and exit without backing up.

• Extend your mirrors so you can see past the boat on both sides.
• Fold or remove anything that adds height or width you don't need.
• Secure the boat and every piece of gear for highway winds, and support the engine or drive for the road.
• Work through our pre-trailering checklist, and check tire pressure on every tire, including the spare.

• Stay centered in your lane and watch both mirrors; oncoming trucks and mailboxes are closer than you think.
• Discover Boating notes some states set a lower speed limit for vehicles towing trailers. Slow down anyway: you'll stop shorter and handle crosswinds better.
• Expect strong side forces from passing trucks and wind on a tall boat.
• Stop after the first few miles and at every stop to check straps, hubs, tires and lights.

Hiring out makes sense when:

• The load needs escorts, route surveys or several states' permits
• Your tow vehicle is near or over its limits
• The boat is tall enough that bridges and overhead lines become a real concern
• You'd need to remove a flybridge, arch or mast to get under height limits

BoatUS points out that most larger boats exceed width restrictions and may be over the height limit, so a good transporter needs experience with state permit agencies. It's also why transporters often ask for a deposit up front, which BoatUS says is often needed to get permits and escorts. See our guide to shipping a boat with a professional transporter.