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Summer 1998
booze & boating

older drivers
98' publications
related links:
  • for more on drinking & boating, visit the HSRC's press release section.
  • for more on alcohol studies, visit the HSRC's public information section.
  • Booze & boating:
    Study examines the role alcohol plays in boating fatalities

    story contents: introduction | are boaters drinking? | talking to families | findings


    An interviewer prepares for a day on the water.

    Introduction

    Shaking a red die in a covered plastic cup, Chad Sattler surveyed a small cove of Jordan Lake, N.C. where
    three small fishing boats gently undulated on the water. The die in the cup came to a standstill. Sattler leaned forward in the seat of the small boat he was in and peered to see how many dots faced up. "Five," he said to his fellow boat-mate Matt Schmink, then pointed to the boat furthest to his right. Taking his cue, Schmink started the trolling motor of their boat and steered in that direction. When the two got within shouting distance of the fishing boat, Sattler hollered out a "hello" then launched into an explanation for their visit.

    "We're from the University of North Carolina and we're out here today doing a boating study," he said. "We were wondering if maybe we could ask you a few questions."

    The lone fisherman gave an affirmative nod.

    "Great!" Sattler said enthusiastically. "Just a minute while we get a little closer."

    This was a frequent scene on North Carolina lakes, sounds and rivers last spring and summer and will be a common sight this year as well. Last spring, Sattler and Schmink along with several other project assistants from the UNC Highway Safety Research Center (HSRC), began collecting data for a study on the prevalence of alcohol consumption among recreational boaters. As part of this study, they used hand-held portable breathalyzers to obtain voluntary breath alcohol measurements from boaters. HSRC researchers hope to use these data to discern the role alcohol plays in boating fatalities and injuries.

    "The die is used to randomly select boats to approach for an interview," said Dr. Rob Foss, Manager of Alcohol Studies at the Center and principal investigator of the five-year study funded by the National Institute on Alcohol Abuse and Alcoholism.

    Cooperation rates for the study have been high so far, Dr. Foss said.

    "From what we've seen, a lot of people are very curious about breathalyzers, whether they've been drinking or not," he said. "They want to know how they work and most boaters help out."

    "We do get some people who are uncomfortable with blowing in a breathalyzer," he added. "The question from a research standpoint is are people who have been drinking more likely to refuse to take the breathalyzer? And the answer to that question -- from what we're seen so far -- is no. There are just some people who, for whatever reason, are uncomfortable providing that information whether they've been drinking or not."

    HSRC researchers used two boats to gather data last spring and summer -- one owned by the Center and one loaned by Logic Marine Corp. of Durham, N.C. All major bodies of water in the state were surveyed with the exception of the Atlantic Ocean.

    "Many people believe that alcohol is a huge problem among boaters, but nobody knows with any validity how much drinking is really going on and whether it plays a causal role in the death or injury of boaters," Dr. Foss said.

    "There have been measures of the level of alcohol in people who have been killed in boating accidents but that's only half the picture," he said. "In order to find out just what role alcohol plays in boating deaths and injuries, we need to find out the amount of drinking that's being done by people out there who aren't injured or killed. Then we can estimate how much drinking increases the chance of dying."

    The project, which continues into the year 2000, is a two-state venture involving North Carolina and Maryland. HSRC is working in conjunction with the UNC Injury Prevention Research Center to gather the North Carolina data, while researchers at the Johns Hopkins University Center for Injury Research and Policy in Baltimore survey Maryland waters. After all the data are collected, the information will be combined and a comparative analysis will be done between the two states.

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    Are boaters drinking?

    North Carolina waters were extensively surveyed by HSRC researchers last year. Voluntary breath alcohol measurements were collected from 1,260 boaters and a 35-question survey with questions about boating experience and drinking practices was completed by 1,174 boaters. Study respondents included fishermen, swimmers, sunbathers, skiers, jet-skiers and boaters out cruising. This spring and summer, the researchers plan to gather more data and expand their coverage of smaller rivers where canoes and kayaks are common.


    Preliminary findings from the first round of North Carolina data collection indicate
    the percentage of North

    Participants blow into a breathalyzer.
    Carolina boaters with elevated alcohol levels is low, Dr. Foss said. Just 2.1 percent of the boat operators and passengers had a blood alcohol content (BAC) above 0.08 percent (the legal limit for boat operators). Eighteen percent of the boaters reported consuming alcohol the day they were interviewed and 14 percent had a BAC above zero, he said.

    "When you talk to people about boating and alcohol, they say, 'Oh gosh yes, everybody's drunk out there.' We're not seeing that at all," he said. "From what we've seen so far, excessive drinking is not nearly as widespread as people think."

    As part of the study, HSRC researchers are investigating North Carolina boating deaths involving alcohol that have occurred over the past nine years. The North Carolina Wildlife Resources Commission is assisting by providing reports on all the state's boating-related deaths from 1989 through 1998. The North Carolina
    Medical Examiner's Office is helping by providing information on alcohol involvement
    for these cases.

    According to Dr. Foss: "An examination of 212 fatalities in these reports showed that 41 percent of the victims had a measurable amount of alcohol in their body when they died."

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    Talking to families

    A portion of the study involves getting information from the families of people who died in these boating accidents, said Bill Tolbert, the study supervisor. This section of the project began last summer when questionnaires were mailed to the families of victims.

    "We're interested in knowing if this person had been treated for any illness such as epilepsy or heart disease just before their death or if they were on some kind of medication at the time that would help us understand what happened," he said. "We're also trying to find out if this person had a drinking problem -- were they heavy drinkers, social drinkers or non-drinkers in general?"

    Another issue the study is looking at is whether the victim could swim, Tolbert said.

    "There's anecdotal evidence that suggests sometimes people with alcohol in their system will just sink," he said. "Strong swimmer, good swimmer, but he sank. He didn't even seem to try. Why is that? Nobody knows. Other times, people will thrash about wildly and then drown. Occasionally-- and this is chilling -- some people swim down. So they go under the water and they're obviously able to swim but instead of swimming to the surface, they swim down, so there's a disorientation factor. There's a hypothesis that alcohol combined with cold water going into your inner ear has the effect of causing disorientation."

    According to Dr. Foss, there are reasons to believe that alcohol contributes more to boating deaths and injuries than to motor vehicle deaths and injuries. This is because passengers who drink in boats are much more at risk of dying than passengers who drink in cars.

    "A lot of people die from drinking and boating not because there's a crash, but because they fall out and drown," he said. "Alcohol can make you fall out of a boat but it generally doesn't make you fall out of a car. It can also help you die after you've fallen out of a boat in ways that don't happen if you fall out of a car."

    In North Carolina, a boat operator is considered legally impaired if the blood alcohol content of the person meets or exceeds 0.08 percent -- the same BAC at which North Carolina motor vehicle drivers are considered legally impaired. "There is no law regarding blood alcohol levels for boat passengers," Dr. Foss said.

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    Preliminary findings

    The study's early findings show some interesting trends, according to Chris Bartley, a graduate research assistant. Passengers, for instance, were nearly twice as likely to have elevated alcohol levels as boat operators. "Nearly 3 percent of the passengers had a blood alcohol level above 0.08 percent while 1.5 percent of boat operators exceeded the legal limit," he said.

    The study also found that:

        •"Non-fishermen" were more than twice as likely as fishermen to have elevated alcohol levels •Boaters who were swimming were nearly twice as likely to have high BAC's as those who weren't swimming
        •And non-zero BAC's were most common among boaters ages 18 to 25, although the incidence of BAC's elevated above 0.05 percent was unrelated to age.

    "All in all, we estimate there are about 14 percent of people out on the water drinking at any given time -- or at least during the hours that we measured -- but very few of those could be considered impaired," Bartley said.

    The UNC researchers interviewed boaters between 11 a.m. and 7 p.m. last year and plan to keep a similar schedule this year. So far, they have found no difference between alcohol levels of boaters on weekends versus weekdays.

    Preliminary findings indicate North Carolina's boating population differs somewhat from that of Maryland, Bartley said. "North Carolina waters tend to be populated by people using small fishing or ski boats, while Maryland has more yachts and large sailboats."

    This spring and summer, Dr. Foss said the researchers plan to gather more information on people riding in smaller boats and on jet-skis.

    "I think we've gotten a substantial proportion of the interviews we need," he said. "The thing we're really under-represented on now is people in rowboats, canoes and kayaks. That's because we've primarily been on big bodies of water -- lakes, sounds and large rivers -- where you tend to see fewer people in smaller boats. This spring and summer we'll be doing some surveying standing alongside smaller rivers and streams."

    So if you're out enjoying the fresh air on a North Carolina river this spring or summer and are flagged down by a couple of people with breathalyzers, you now know that it's simply an HSRC research team out doing a day's work.

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