BUI manslaughter is the boating version of a DUI death, and as of 2025 Florida treats it almost exactly like one. It is a second-degree felony, it now carries a four-year mandatory minimum, and the same two threads that decide a fatal car case decide this one: the forensic fight over the blood and the impairment, and the fight over causation, whether your operation of the vessel is what caused the death. Two new laws reshaped this area in 2025, and it is worth being precise about what each one did.
| Charge | Felony degree | Maximum prison | Mandatory minimum |
|---|---|---|---|
| DUI with serious bodily injury | Third degree | 5 years | None |
| Vehicular homicide | Second degree | 15 years | None |
| DUI manslaughter | Second degree | 15 years | 4 years |
| BUI manslaughter | Second degree | 15 years | 4 years |
| Leaving the scene of a crash involving death | First degree | 30 years | 4 years |
| DUI second-degree murder | First degree | Life | None |
License consequences vary by charge, from a minimum three-year revocation to permanent revocation, and fines and sentencing-scoresheet points are additional. See each page for the full penalty and defense picture.
What BUI manslaughter is, and the four-year floor
Under section 327.35, BUI manslaughter is operating a vessel while impaired or with a blood or breath alcohol level of 0.08 or higher and, by reason of that operation, causing or contributing to a death. It is a second-degree felony, punishable by up to fifteen years and a $10,000 fine, and a conviction now carries a four-year mandatory minimum that a judge cannot go below. As with DUI manslaughter, there is no separate negligence element. Impairment and causation are the two things the State has to prove, and causation is usually where the case lives.
Lucy’s Law and Trenton’s Law, what changed and when
Two separate 2025 laws raised the stakes, and they are often confused. Lucy’s Law, effective July 1, 2025, is what added the four-year mandatory minimum for BUI manslaughter and brought boating penalties into line with the driving offenses. Trenton’s Law, effective October 1, 2025, is what makes BUI manslaughter a first-degree felony, punishable by up to thirty years, when the boater has a prior conviction for DUI or BUI manslaughter, vehicular homicide, or vessel homicide, and it also made refusing a lawful breath or urine test a separate crime. BUI manslaughter also rises to a first-degree felony if you left the scene without giving information and rendering aid.
Causation is the same fight on the water
The State does not get a conviction just because there was drinking, a vessel, and a death. It has to prove that your operation of the vessel caused or contributed to the death. If the victim’s own conduct, another vessel, or a mechanical failure caused the collision, or if a sober operator in the same position would have had the same crash, then your operation did not cause or contribute to the death. On the water, reconstruction looks at the wake, the right-of-way and navigation rules, visibility, the positions and speeds of the vessels, and any mechanical issue, and that reconstruction is where a manslaughter charge often comes apart. The DUI manslaughter page walks through the same causation analysis on the road.
The stop and the field sobriety exercises
Two features of boating cases create defense ground you do not have on the road. First, as of July 1, 2025, the Boater Freedom Act bars officers from stopping or boarding a vessel for a routine safety check without probable cause, so a stop that began as a random safety inspection, rather than on an observed violation or genuine probable cause, is open to challenge. Second, the field sobriety exercises themselves are unreliable on a boat. The standardized battery was built and validated for stable ground, not a pitching deck, and the seated or afloat tasks officers substitute are affected by sun, wind, wave motion, fatigue, and inner-ear disturbance, all of which mimic the very signs the officer is grading. How those exercises were administered and scored is open to challenge.
The blood and the forensic challenge
A fatal boating crash, like a fatal car crash, usually sends the operator to a hospital and produces a blood draw rather than a breath test. That opens the same forensic challenges I bring in any blood case: the draw, the storage, the chain of custody, and the gas chromatography analysis. Florida law lets an officer demand a blood draw where there is probable cause that an impaired operator caused a death or serious bodily injury, but the probable cause and the procedure still have to hold up, and an unreliable result can take the State’s number off the table. This is the heart of my forensic practice. The blood test, boating under the influence, and search and seizure pages go deeper.
I started out as an Assistant Public Defender in Florida’s Thirteenth Judicial Circuit, in Tampa, and today I am one of six ACS-CHAL Forensic Lawyer-Scientists in Florida. These are the cases where the science and the causation decide everything, where an unreliable blood result or an unproven causal link is the difference between a manslaughter conviction and a far lesser charge. I bring the forensic and the crash-reconstruction fight that these cases turn on. Learn more about my background.
Related: the serious and felony DUI overview, DUI manslaughter, boating under the influence, the blood test, and search and seizure.
Florida BUI manslaughter questions
What is the penalty for BUI manslaughter in Florida?
BUI manslaughter is a second-degree felony under section 327.35, punishable by up to fifteen years in prison, and as of July 2025 it carries a four-year mandatory minimum. It rises to a first-degree felony, up to thirty years, if you left the scene without rendering aid or, since October 2025, if you have a qualifying prior conviction.
Did the law on BUI manslaughter change recently?
Yes, twice in 2025. Lucy's Law, effective July 1, 2025, added the four-year mandatory minimum and aligned boating penalties with the driving ones. Trenton's Law, effective October 1, 2025, made BUI manslaughter a first-degree felony when the boater has a prior conviction for DUI or BUI manslaughter, vehicular homicide, or vessel homicide, and made refusing a test a separate crime.
Can BUI manslaughter be reduced?
Yes, and causation is usually the lever, just as in a fatal car case. If the State cannot prove your operation of the vessel caused or contributed to the death, or if the blood evidence is unreliable, the charge can move toward vessel homicide or a lesser offense. Because of the four-year mandatory minimum, getting below the manslaughter charge is usually the whole goal.
How are boating sobriety exercises different from roadside ones?
A boat is not a roadside. The standardized field sobriety exercises were designed and validated for solid ground, not a moving deck, so officers use seated or afloat tasks whose reliability is far weaker. Sun, wind, wave motion, fatigue, and inner-ear effects all mimic impairment, which gives real room to challenge how the exercises were administered and scored.
What if another vessel or the victim was at fault?
It can decide the case. If the victim's own conduct, another boater, or a mechanical failure was the cause of the collision, then your operation did not cause or contribute to the death, even if you had been drinking. These are reconstruction cases as much as blood cases.
This page is general information about Florida law, not legal advice, and it does not create an attorney-client relationship. The charges discussed here are governed by sections 316.193(3), 316.027, 327.35, and 782.071, Florida Statutes, and the 2025 changes under Trenton’s Law apply to offenses on or after October 1, 2025. Every case turns on its own facts, and past results do not guarantee a similar outcome.
