Seagirt Marine Terminal handled 1,113,309 TEU in 2025, and Ports America Chesapeake reports truck turns under 30 minutes for a single move. The terminal is not where Baltimore containers get expensive. They get expensive in the days after discharge, when two separate clocks start running and nobody on the shipper’s side is watching them. This guide explains the clocks, the chassis and the permits, and how to plan a pickup that beats all three.
Drayage, defined
Drayage is the truck move between the marine terminal and the first inland point: a warehouse, a transload dock, a rail ramp or a customer. It is short in miles and heavy in rules. The driver needs a TWIC card to enter the terminal, the container needs a release from the ocean carrier and customs, the move needs a chassis, and the route needs to fit the load. In Baltimore it also needs to fit the harbor tunnels.
The two clocks
| Clock | Where the box is | Who charges | What stops it |
|---|---|---|---|
| Demurrage | On the terminal, after discharge | Ocean carrier or terminal | Pulling the container out of the terminal |
| Detention (per diem) | Off the terminal, in your possession | Ocean carrier | Returning the empty to the designated depot |
Free time is the number of days each clock allows before charges begin. The ocean carrier sets it in the tariff or the contract. Terminal free time counts from discharge and availability, not from vessel arrival. Detention free time counts from the gate-out. The two are usually different numbers, and weekends and holidays may or may not count.
The fear is a box that clears customs on a Friday, sits over a weekend because no chassis was booked, pulls on Tuesday, waits at a distant dock until the following week, and comes back empty ten days later. Two sets of charges, one container. The relief is a plan built before the ship docks.
Chassis provisioning
A chassis is the trailer frame the container rides on. In Baltimore, who supplies it depends on the ocean carrier and the drayage partner. Some moves use a pool chassis the carrier arranges. Some use the trucker’s own equipment. A tri-axle chassis is needed for overweight boxes, and a genset chassis for a reefer that must stay powered on the road.
The rule is simple. Book the chassis when you book the truck, and confirm the type. A missing or wrong chassis is the most common reason a pickup slips a day, and a slipped day is a demurrage day.
Overweight permits
Highway weight limits apply to the tractor, chassis and container together. A heavy box, common in metals, beverages, paper and machinery parts, can exceed the legal gross weight for a standard setup. It then needs an overweight permit from the state and usually a tri-axle chassis. The permit names the route. The route must respect the tunnel limits. Send the gross weight per container with the booking so the permit and the chassis are arranged before the box is available.
The tunnel rules for hazmat boxes
Since the Key Bridge collapse on March 26, 2024, every cross-harbor truck uses the I-95 Fort McHenry Tunnel or the I-895 Harbor Tunnel. Placarded hazmat may not enter either tunnel. Neither may anything over 14 ft 6 in high or 11 ft wide. Those loads loop the west side of I-695, about 30 to 35 extra miles and 45 to 60 minutes.
Seagirt sits on the east side of the harbor with Dundalk and Sparrows Point. So a hazmat container out of Seagirt has two good options: a hazmat-permitted partner warehouse on the east side, which never touches a tunnel, or the west loop planned and priced in advance. The bad option is a dispatch that assumes the tunnel. The Key Bridge routing page has the full lane table.
How to plan a pickup that beats the clocks
- Get the free days in writing before arrival. Terminal and detention free time, and whether weekends count.
- Clear customs before discharge. Customs clearance is coordinated through our licensed customs broker partners so the release is in place when the box is available.
- Book the truck and the chassis for day one of availability. Confirm gate hours with Ports America Chesapeake on the day, since they vary.
- Unload close to the port. A transload partner on the east side empties the container on the day of pickup. The empty goes back the same or next day, and your freight continues in a 53 ft trailer with no per diem exposure.
- Flag weight, hazmat and dimensions in the booking. Permits, chassis type and route all follow from them.
- Use storage to break a long delivery window. If the customer cannot receive for two weeks, a partner warehouse near the port is cheaper than two weeks of detention.
How Baltimore 3PL uses this
The desk tracks both clocks for every container and books the drayage partner, the chassis and any permit before the box is available. Hazmat boxes go to hazmat logistics partners routed for the tunnels. Containers that cannot deliver on discharge day go to a transload or warehouse partner on the east side so the empty returns inside free time.
What to send for a quote
- Container numbers, sizes and count, with the ocean carrier and vessel
- Free time on the bill of lading and the expected availability date
- Gross weight per container and any hazmat class and UN number
- Delivery address and receiving hours
- Whether you want transload to 53 ft trailers or short-term storage near the port
Send it to the quote desk and you get a dispatch plan with both clocks mapped within one business day.
Questions shippers ask
01What is the difference between demurrage and detention?
Demurrage is charged while a container sits on the terminal past its free days. Detention, often called per diem, is charged while the container is outside the terminal past its free days. They are separate clocks with separate free time.
02When does free time start at Seagirt?
Terminal free time starts when the container is discharged and available, not when the vessel arrives. Check the carrier’s tariff for the count and whether weekends and holidays are included.
03Who provides the chassis in Baltimore?
It depends on the ocean carrier and the drayage partner. Some moves use a pool chassis, some use the trucker’s own chassis. Confirm the arrangement when you book, because a missing chassis is the most common reason a pickup slips.
04What is an overweight container?
A loaded container that exceeds legal highway weight for a standard tractor and chassis. It needs a state permit and often a tri-axle chassis, and the permit names the route.
05Can a hazmat container use the Baltimore tunnels?
No. Placarded hazmat may not enter the I-95 Fort McHenry Tunnel or the I-895 Harbor Tunnel. It loops the west side of I-695, about 30 to 35 extra miles, or stays on the same side of the harbor where it landed.
06How do I avoid per diem?
Return the empty inside the free days. The surest way is to unload the container at a transload partner near the terminal on the day of pickup and return it the same or next day, so the box never waits at a distant dock.