A DNR warden or Sheriff’s deputy pulls alongside your boat, and for a moment it doesn’t feel like a traffic stop. You’re on the water. It’s summer. But the legal process that follows a boating under the influence stop in Wisconsin is every bit as serious as anything that happens on a highway, and the mistakes people make in those first hours often come from assuming the two situations work the same way. They don’t. BUI operates under its own statute, its own evidentiary rules, and its own procedural framework. The defenses available on the water are meaningfully different from what applies in an OWI case on land.
At Melowski & Singh, LLC, we’ve achieved over 1,000 DUI dismissals or non-alcohol-related charge reductions since 1993 by building strategies around how each charge actually works, not how it appears to work at first glance. BUI is no exception.
BUI Is Its Own Charge Under Wisconsin Law
Boating under the influence is governed by Wisconsin Statute 30.681, entirely separate from the OWI statute that applies on land. That separation isn’t a technicality. It produces real differences in how cases are charged, how penalties escalate, and what procedural rules govern the investigation.
One of the most significant distinctions involves prior convictions. Under Wis. Stat. 30.681, prior BUI convictions and prior OWI convictions don’t cross-count. A person with an OWI on their record who is charged with a first BUI is treated as a first-offense BUI under that statute, not a second offense. This has direct consequences for penalty exposure and how the case should be approached.
The felony threshold is another place where BUI and OWI diverge sharply. A fourth OWI conviction in Wisconsin is a felony. BUI never escalates to a felony, regardless of how many prior offenses are on someone’s record. That distinction shapes the entire resolution of a case: what options are worth pursuing and what risks are actually on the table. There’s also a zero-tolerance rule that applies specifically to boat operators under 21. Any BAC above 0.0 triggers a violation under Wis. Stat. 30.681(1)(bn), which is separate from the general prohibited alcohol concentration standard that applies to adult operators and has nothing to do with whether passengers may legally possess alcohol aboard.
How Sheboygan County Enforces BUI on the Water
The enforcement environment in Sheboygan shapes how stops are initiated and documented. The Sheboygan County Marine Unit, operating under the Sheriff’s Department, patrols Lake Michigan with a 27-foot Safe Boat WAC and inland lakes with a 17-foot Boston Whaler. The patrol season runs from mid-May through the end of September. The unit coordinates with the Wisconsin DNR, US Coast Guard Station Sheboygan, and the Sheboygan Fire Department, enforcing boating regulations under Chapter 30 of the Wisconsin State Statutes. BUI cases are processed through Sheboygan County Circuit Court in the 4th Judicial District.
Enforcement pressure spikes further during Operation Dry Water, a national BUI campaign that concentrates patrol presence on major boating weekends throughout the summer. During those windows, coordination between the Marine Unit, the DNR, and the Coast Guard is active and deliberate.
One point worth understanding: open alcohol containers aboard a vessel aren’t, by themselves, grounds for a BUI stop or investigation. Officers need separate indicators of impaired operation before a BUI investigation can lawfully begin. That threshold matters, and it’s one of the first things we examine in any case.
The Evidentiary Problems Built into Every BUI Stop
Evidence gathered on the water is subject to conditions that don’t exist at a roadside stop, and those conditions create legitimate defense angles that a prepared attorney will pursue.
Marine Field Sobriety Tests
Wisconsin uses four seated marine field sobriety tests in BUI investigations: horizontal gaze nystagmus (HGN, a test in which the officer tracks involuntary eye movement as a potential indicator of impairment), finger-to-nose, palm pat, and hand coordination. These tests are conducted aboard a patrol vessel, not on stable ground. Wave action, vessel vibration, prolonged sun exposure, heat, and dehydration can all affect performance in ways that mimic the signs of alcohol impairment. Someone who spent six hours on the water in July sun before a stop may perform poorly on a coordination test for reasons that have nothing to do with what they drank.
The Preliminary Breath Test Admissibility Rule
Under Wis. Stat. 30.682(3), the result of the preliminary breath screening test administered on the water isn’t admissible at trial. It may be used only to establish probable cause for arrest. The evidentiary chemical test (the reading that actually matters in court) is a separate step governed by Wis. Stat. 30.684, with different statutory authority and different procedural requirements that can’t simply be carried over from land-based OWI defense.
Implied Consent & Advisement Failures
Wisconsin’s implied consent law for boating, codified in Wis. Stat. 30.683, requires that a boat operator submit to chemical testing when lawfully requested. But the officer making that request must properly advise the operator of the consequences of refusal at the time of the request, as required by Wis. Stat. 30.684(1)(b). If that advisement is missing, incomplete, or given out of sequence, that procedural failure may provide grounds for relief on a refusal charge. This is a defense avenue that none of the commonly cited Wisconsin BUI resources address in any meaningful depth.
What a BUI Defense Actually Involves
A realistic BUI defense starts at the stop itself. The authority framework for a marine stop differs from a traffic stop, and the basis for initiating contact with a vessel must meet its own legal standard under Chapter 30. If that threshold wasn’t met, the stop is challengeable regardless of what evidence followed.
From there, a thorough defense looks at chemical test procedures, equipment calibration records, chain of custody for any blood draws, and whether the required implied consent advisements were given correctly and in the proper sequence. These are reviewable angles specific to BUI procedure under Chapter 30 that don’t map cleanly onto OWI defense practice.
We prepare every case for trial. That’s not a marketing phrase. It’s why we’ve achieved over 1,000 DUI dismissals or non-alcohol-related charge reductions since 1993. Quick resolutions that don’t serve the client aren’t something we pursue, and the same standard of preparation we bring to OWI defense applies to every BUI case we handle statewide.
If you were stopped on the water in the Sheboygan area, reach out to Melowski & Singh, LLC at (920) 294-1414 to talk through where your case stands.