7 Reasons an In-Water Survey Gets Rejected by Class

By Nadia Fournier, Marine surveyor and insurance adjuster. Reviewed by Dana Whitcombe, technical reviewer.

Ship Husbandry & In-Water Repair | Hull & Bottom Cleaning The owner called me on a Tuesday. He had a 67-foot coastal tug, insurance had lapsed, and the sale hinged on a class-approved in-water survey. I'd done the underwater part that same week—four dives, three hours, water temperature 48°F and visibility barely two feet. The footage was terrible. The class surveyor rejected it before I even sent the invoice. The discharge letter said everything was inadequate: clarity, documentation, calibration, even the diver's name. I've been on the wrong side of these notices for twelve years. Every one follows a pattern. Here are the seven reasons an in-water survey gets rejected by class—and how to fix each one before you buy the tanks.

Reason 1: You Dived in the Wrong Water

The class guide says minimum visibility: one meter. Not a suggestion. On the Anacortes tug, it was 0.5 feet. Why does that matter? Because a surveyor must be able to see pitting, cracks, and weld seams. If the water is soup, you're guessing. You'll miss a fracture that class will find later—or they'll know you never saw the bottom. The fix: run a Secchi disc or a turbidity probe before you splash. If it's below the threshold, reschedule. Most charters allow a 24-hour hold window. Use it. If the weather's coming, don't dive a boat in a harbor with muddy runoff. The surveyor will see a wall of murk, and so will the class file. One more thing: even if the visibility meets the minimum, remember that the requirement is not just for the lens—it's for the light. You may also need additional lighting on the ROV or diver torch to guarantee the photos aren't just spots in the gloom.

Reason 2: Your Thickness Gauge Had an Expired Certificate

Ultrasonic wall-thickness readings are the backbone of an in-water hull survey. Class requires the gauge to carry a current calibration certificate from a certified lab—traceable, with a recent date. I once grabbed a gauge from the truck without checking. Certificate was nine months old; class wants six months for that instrument. The rejection came back citing 'non-compliant measurement equipment.' You can't argue with a stamped paper. The fix: log the serial number, check the cert before you load the gear, and carry a copy. If it's expired, borrow one from a surveyor who knows. Keep the certificate in a waterproof pouch on the survey vessel. In my case, the gauge was sitting under a seat for a month, and the salt air probably didn't help. Some class societies also require the probe to be certified for underwater use, not just the instrument. Don't learn that after the invoice is mailed.

Reason 3: Your Diver Wasn't Class-Approved

In-water surveys are often done by a class-recognized underwater surveyor or a diver working under their direct supervision. 'Commercially certified' doesn't mean 'class recognized.' My Anacortes diver had a commercial card and a lot of hours, but his name wasn't on the class directory. The rejection note said the inspection was 'not carried out by an approved specialist.' That's a one-way ticket. The fix: ask your class society for its list of approved underwater surveyors and work with one. Or find a surveyor with the class endorsement on his license. The approved list is not just a formality. It exists because in-water inspections involve life-critical decisions: hull thickness, corrosion, fatigue. Class wants to know the person writing the report has the credentials to call out a defect and the authority to stop the survey. So when you hire a diver, ask for their class profile. If they can't produce one, you're not hiring a surveyor—you're hiring a swimmer with a GoPro.

Reason 4: The Video Had a Black Hole

The class report must document every area of the hull—continuously. My Anacortes footage had a 20-second gap under the keel where the camera operator forgot to press record. Class couldn't confirm the keel, so the entire survey was void. They don't want to review your greatest hits; they need an unbroken pass from bow to stern, both sides, turn at the bootstripe, and return. Label each clip with location, time, and date. Use a fixed camera rig, not a handheld that blocks the view. If you can't prove you saw it, you didn't see it. The class reviewer will zoom into the timestamp, not just the image. If you don't have a clear clock running, they'll question the sequence. Many survey teams now use a wide-angle camera with a depth sensor and GPS overlay—small investment compared to a rejected survey. And always record a 'close of pass' shot from the stern, so the reviewer can count the frames and see the full run.

Reason 5: You Didn't Ask Permission First

Classification societies require advance notice and approval of the survey plan. On the tug, I started the day after the owner called; the class office had a 30-day notification requirement for in-water surveys. They rejected the report because it wasn't 'scheduled in accordance with class procedures.' You can't retroactively fix a timeline. The fix: check your class society's rules for planned inspections, submit a formal request with the proposed method, time, and location, and wait for written confirmation. It's a pain, but it turns a trip into file. The 30-day window sounds ridiculous when the weather turns and the tide waits for no one. But that's the rule. Class has to assign a surveyor to review your submission, and if they haven't received the paperwork in advance, they'll bounce it. Some societies let you do a preliminary inspection then send a formal plan for approval. I skip the preliminary and go straight to a written confirmation email with the class surveyor's name and date of approval. That email is your best friend.

Reasons 6 and 7: The Hull Itself Said 'No'

This last rejection covered two separate issues, and they usually arrive together. Reason 6: The discovered condition exceeds the limits for an in-water survey. When my diver found pitting at 40% of the frame thickness on a stanchion, class rule says the inspection must stop and the vessel goes to dry-dock. The in-water survey can't be accepted because it's no longer a routine condition assessment; it's a damage assessment. Reason 7: The hull wasn't fit for inspection in the first place. Four years of barnacle accumulation on the tug's bottom meant the diver was inspecting a carpet, not steel. Class will reject any report made while marine growth obscures the surface. The fix: plan to clean the hull just before the survey—either with a brush or a dive team that preps it—and have the class surveyor confirm it's acceptable before you begin. That's the difference between a survey that stands and a piece of wet paper. To be clear, this section is really two rejections in one, so the class letter often lists them separately. First, if the hull shows damage beyond the tolerances set for in-water surveys, class will not accept any in-water report for that hull. It's not that your survey was poor—it's that the method is not permitted for that condition. The decision to move to dry dock is usually made by the class surveyor in the field, not by you. Second, even with clean water and good visibility, a fouled hull means you cannot verify the shell plating or welds. Class has a rule: the hull must be clean enough to permit a close visual inspection. Marine growth is not just a nuisance; it's a safety issue because it hides corrosion. The only fix is to brush the hull beforehand, and if you can't get it clean enough, don't start the survey.

Frequently Asked Questions

If class rejects my in-water survey, can I just do another one and submit it? You can re-submit, but class will want to see the specific deficiency addressed—clear water, approved surveyor, or clean hull. You can't simply redo the video; the entire survey may need to be redone if the original wasn't completed to the rule. Check with your surveyor before you reschedule. What happens if the in-water survey finds damage too severe for that kind of inspection? The survey stops and the vessel must be dry-docked for a full bottom survey. Class will treat the in-water survey as void for that section, and the dry-dock survey is the only way to get an approved condition report. Budget for it. How much notice does class actually need for an in-water survey? It varies by society, but typically 14–30 days. Always check the specific rule. Starting work without approval is a guaranteed invitation to a rejection letter.