When a brand-new vessel hits the water, the last thing anyone expects is a sanitation issue. But even the most advanced systems can run into trouble if they’re not installed or used correctly. Recently, we were called out to troubleshoot an issue involving an AHEAD tank MSD installation on a new vessel—and it turned into a great reminder of why proper installation and education matter just as much as the equipment itself.
The Problem: Toilets Not Flushing & Tank Backing Up
The vessel had recently been outfitted with an AHEAD tank, a Type II Marine Sanitation Device designed to provide reliable and efficient marine waste management. However, the crew quickly noticed that the toilets were not flushing properly. Even worse, the AHEAD tank was backing up—never a good sign on a new build.
When sanitation systems fail to perform as expected, the first step is always a thorough inspection.
The Inspection: What We Found
Upon opening and inspecting the AHEAD tank, we immediately discovered one of the core issues: paper towels had been flushed into the system.
This is a big no-no.
Marine sanitation systems are designed for human waste and marine-grade toilet paper only. Paper towels do not break down like marine toilet paper. Instead, they clump together, restrict flow, and can clog pumps, macerators, and tanks. In this case, the buildup of paper towels was directly contributing to the tank backup and flushing failure.
But that wasn’t the only issue.
The Installation Oversight: Venting Problems
During our inspection, we also found that the installers had:
- Removed the blue vent from both the AHEAD tank and the behind tank
- Hard-plumbed the vent connections together
- Eliminated proper vent access points
Proper venting is critical in marine sanitation systems. Without correct airflow, tanks cannot equalize pressure. This leads to poor flushing performance, slow drainage, and in some cases, tank backup—exactly what was happening here.
The removal of the blue vent access eliminated a key component designed to ensure proper airflow.
The Fix: Restoring Proper Function
We tackled the issue in several steps:
- Removed the Paper Towels
All paper towel buildup was cleared from the AHEAD tank to restore proper flow and eliminate obstructions.
- Educated the Captain & Crew
We advised the boat captain that no paper towels are to be flushed under any circumstances. Clear usage guidelines are just as important as correct installation and misuse can quickly lead to costly downtime.
- Corrected the Venting Configuration
We:
- Removed the hard plumbing on the blue vent access
- Reinstalled the proper blue vent components
- Plumbed both air vents using long sweep 90-degree fittings
- Routed the venting properly to exit the vessel up and out
Using long sweep 90s instead of tight angles improves airflow and reduces the risk of restriction. Proper upward vent routing ensures tanks can breathe as designed, preventing pressure buildup and restoring reliable flush performance.
The Result: System Back to Proper Operation
Once the paper towels were removed and the venting was restored to proper configuration, the sanitation system returned to normal operation. Toilets flushed correctly, the tank no longer backed up, and the vessel was ready to operate as intended.
Lessons Learned
This installation reinforced a few key principles:
- Use the system as designed — Only flush approved materials.
- Never bypass critical components — Vent systems exist for a reason.
- Proper airflow is essential in marine sanitation systems.
- Education prevents repeat issues — Crew awareness is vital.
The AHEAD tank itself performed exactly as engineered—the issues stemmed from misuse and improper vent plumbing. Once corrected, the system functioned flawlessly.
A properly installed and properly used Type II Marine Sanitation Device is something you never have to think about. And on the water, that’s exactly how it should be.
