Boat Trailer Research Articles

Incorporating Time-Lapse Digital Cameras into Creel Surveys at Three Alabama Reservoirs

Abstract We compared different creel survey methods at three Alabama reservoirs (Harris, Jordan, and Mitchell) to identify approaches that could improve precision. We were particularly interested in whether boat trailer counts from time-lapse photos taken at boat ramp parking lots could be used as an index of fishing effort to improve the temporal coverage of sampling. Angler effort was estimated independently using roving creels, access point creels, and aerial census counts and compared with fixed-location digital camera images of trailers at boat ramps. Digital camera counts of trailers correlated with angler effort from aerial census, access point creel surveys, and roving creel surveys. This finding suggests that time-lapse digital cameras as a sampling method to obtain angler effort may provide a feasible method once calibrated to a system. Best-fitting models for relationships between time-lapse trailer counts and the other creel methods included covariates for season and day type (weekend versus weekday) effects, but not reservoir and time-of-day effects. The inclusion of effort predicted from time-lapse digital cameras incorporated with roving creel surveys did not statistically affect the magnitude of effort estimates but substantially increased the precision of effort estimates.

Limited success of the non-indigenous bivalve clam Rangia cuneata in the Lithuanian coastal waters of the Baltic Sea and the Curonian Lagoon

Summary The gulf wedge clam, common rangia Rangia cuneata, with a native origin in the Gulf of Mexico has spread to north European brackish and freshwaters. This semitropical species is able to survive in conditions of low winter temperatures in boreal environment of the Baltic Sea. Its expansion within lagoons and sheltered bays in the southern and eastern parts of the Baltic Sea appears to be with natural spread and its discontinuous distribution is likely to have been with shipping, either within ballast water or as settled stages transported with dredged material. In this account, we report on the occurrence of R. cuneata in Lithuanian waters. We compare habitats of the common rangia in the Curonian Lagoon and in the exposed coastal waters of the Baltic Sea. We notice high mortality of the species in the Lithuanian waters in comparison to the neighboring Vistula Lagoon. Based on finding of small specimens of R. cuneata attached to the spiked watermilfoil Myriophyllum spicatum, we indicate a risk of local spread with movements of fishing equipment and snagged plants on anchors or boat trailers removed from the water. We discuss the possibility of further spread of the common rangia to similar environments in the Baltic Sea and elsewhere in Europe.

Using a novel spatial tool to inform invasive species early detection and rapid response efforts.

Management of invasive species has increasingly emphasized the importance of early detection and rapid response (EDRR) programs in limiting introductions, establishment, and impacts. These programs require an understanding of vector and species spatial dynamics to prioritize monitoring sites and efficiently allocate resources. Yet managers often lack the empirical data necessary to make these decisions. We developed an empirical mapping tool that can facilitate development of EDRR programs through identifying high-risk locations, particularly within the recreational boating vector. We demonstrated the utility of this tool in the Great Lakes watershed. We surveyed boaters to identify trips among water bodies and to quantify behaviors associated with high likelihood of species transfer (e.g., not removing organic materials from boat trailers) during that trip. We mapped water bodies with high-risk inbound and outbound boater movements using ArcGIS. We also tested for differences in high-risk behaviors based on demographic variables to understand risk differences among boater groups. Incorporation of boater behavior led to identification of additional high-risk water bodies compared to using the number of trips alone. Therefore, the number of trips itself may not fully reflect the likelihood of invasion. This tool can be broadly applied in other geographic contexts and with different taxa, and can be adjusted according to varying levels of information concerning the vector or species of interest. The methodology is straightforward and can be followed after a basic introduction to ArcGIS software. The visual nature of the mapping tool will facilitate site prioritization by managers and stakeholders from diverse backgrounds.

The Use of Sophisticated Materials in the Construction of an Ultra-Light Trailer

This paper aims to study ultra-light materials, which will replace the conventional materials used in the production of trailers. Conventional materials used for the production of trailer frames are: galvanized steel or steel with untreated surface and various coatings. In addition to high strength, steel is characterized by a high specific weight, which significantly increases the weight of the trailer and reduces the permissible load. Therefore it is necessary to look for other materials that have a lower specific weight, but in the same time they meet strength requirements. The designed boat trailer has 25% less weight than the lightest boat trailer available on the European market.

A boat hitchhiker’s guide to survival: Cabomba caroliniana desiccation resistance and survival ability

Cabomba caroliniana is a submersed macrophyte that has become a serious invader. Cabomba predominantly spreads by stem fragments, in particular through unintentional transport on boat trailers (‘hitch hiking’). Desiccation resistance affects the potential dispersal radius. Therefore, knowledge of maximum survival times allows predicting future dispersal. Experiments were conducted to assess desiccation resistance and survival ability of cabomba fragments under various environmental scenarios. Cabomba fragments were highly tolerant of desiccation. However, even relatively low wind speeds resulted in rapid mass loss, indicating a low survival rate of fragments exposed to air currents, such as fragments transported on a boat trailer. The experiments indicated that cabomba could survive at least 3 h of overland transport if exposed to wind. However, even small clumps of cabomba could potentially survive up to 42 h. Thus, targeting the transport of clumps of macrophytes should receive high priority in management. The high resilience of cabomba to desiccation demonstrates the risk of continuing spread. Because of the high probability of fragment viability on arrival, preventing fragment uptake on boat trailers is paramount to reduce the risk of further spread. These findings will assist improving models that predict the spread of aquatic invasive macrophytes.

The 100th Meridian Initiative at the Lake Mead National Recreation Area, NV, USA: Differences between boater behaviors before and after a quagga mussel, Driessena rostiformis bugensis, invasion

The 100 th Meridian Initiative was developed to help prevent the spread of aquatic nuisance species (ANS) through boater education and research on boater movement patterns and behaviors. Surveys employing these elements were conducted at Lake Mead National Recreation Area (LMNRA) in 2002-2003 before the discovery of the quagga mussel (Dreissena rostiformis bugensis Andrusov 1897) and in 2007-2008 after an established population of quagga mussels was found in the Lake. Boaters were asked questions in a personal interview or a mail-in survey regarding what body of water they had previously launched their watercraft in, where they were planning to launch next, if they cleaned their watercraft between each launch, and if they were aware of quagga mussels or other ANS. Results from the personal interviews and mail-in surveys indicated a significant increase in mussel awareness between the pre- and post- mussel invasion groups. Cleaning habits between the study periods for both interviews and mail-in surveys did not differ significantly. Boat trailer states of registration were also documented in both study periods in the parking lots of LMNRA. In 2002-2003, 0.6% of the trailers documented were from states with known zebra or quagga mussel populations, whereas in 2007-2008, 98.2% of states documented had known zebra or quagga mussel populations. Increased boater awareness will help prevent the spread of aquatic invasive species and the 100 th Meridian Initiative is a helpful way to educate boaters and collect relevant data on future mussel invasions. The preservation of natural waters is vital for the conservation of native species and the prevention of zebra and quagga mussel invasions will assist in this preservation. Further efforts should be directed toward educating boaters on effective cleaning methods.

Sliding friction of sea ice blocks

Abstract Sliding friction is known to be the largest energy sink during ridging events and it controls the force during rafting. During the 1994 Sea Ice Mechanics Initiative (SIMI), we conducted a set of sliding friction tests by pulling meter-size blocks of sea ice over the natural ice cover to determine the friction coefficients. The ice blocks were similar in size to those occurring in natural rafting and ridging events. Our simple tests were conducted by pulling the blocks using a boat trailer winch and cable. This system was definitely compliant, and elasticity of the cable was an important property that gave rise to stick–slip behavior comparable to that observed during rafting and ridging events. A simple model was introduced to analyze the data. It proved useful in understanding the stick–slip response, and exposed the proper way to interpret results. Static and dynamic friction coefficients are presented for 25 test cases for blocks of various sizes pulled over ice covered with no snow and a small amount of snow. The model shows how to interpret the friction coefficients in this compliant system correctly. Interestingly, static and dynamic friction coefficients do not occur at the times of maximum and minimum pulling forces, respectively.

Assessing patterns of recreational use in large marine parks: A case study from Ningaloo Marine Park, Australia

Being able to accurately locate and describe recreational use within marine parks is essential for their sustainable management. Given the difficulty in accessing many marine parks, as well as their large size, the surveys to obtain these much-needed data are often logistically challenging and expensive. Aerial surveys are one potential method for obtaining accurate, timely data and this paper details the design for one such survey conducted in the Ningaloo Marine Park, off the northwestern coast of Australia. Ningaloo has been nominated as a world heritage site and the fringing coral reef that forms the centrepiece of the Marine Park extends for 300 km along the coastline. The survey involved 34 temporally stratified flights conducted over a 12-month period. All vessels and people were geo-referenced and where possible, their activities were recorded, providing data that clearly illustrates dramatic expansions and contractions in recreational use. Not only does the spatial extent of use expand in the peak visitor season (April–October), the density of use correspondingly increases. High densities of recreational activity in the Park’s waters were accompanied by increased numbers of vehicles, camps, boat trailers and boats on the adjacent shoreline. Aerial surveys proved to be an effective method for rapidly obtaining recreational data with high spatial accuracy. Such a method has broad applicability to marine parks as it provides comprehensive data to benchmark existing recreational use, as well as monitor future changes in activity patterns, which are essential for the informed management that must underpin sustainability efforts.

Assessing the effects of application time and temperature on the efficacy of hot-water sprays to mitigate fouling by Dreissena polymorpha (zebra mussels Pallas)

Dreissenid mussel (Dreissena polymorpha, Dreissena rostriformis bugensis) expansion into the Western US has renewed interest in hot-water spray mitigation of mussel fouling on boat hulls, trailers, and other equipment. However, the efficacy of hot-water sprays to mitigate dreissenid fouling has not been experimentally assessed. Emersed, adult D. polymorpha were exposed to low-pressure, hot-water sprays at 40, 50, 60, 70, and 80°C for 1, 5, or 10 s. Sprays at ≥60°C for 10 s or 80°C at ≥5 s were 100% lethal. In contrast, 1–10 s exposures did not induce 100% mortality at ≤50°C. The results indicate that mitigation of D. polymorpha fouling, especially in areas protected from the hydraulic impacts of high-pressure sprays requires spray temperatures of > 80°C applied for >5 s or no less than 60°C applied for >10 s. Thus, presently recommended spray temperatures of ≥60°C may not be 100% effective unless applied for >10 s.

Strain-Aging as a Failure Mechanism in Boat Trailers

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

An assessment of the recreational fishery in the St Lucia estuarine system, KwaZulu-Natal, South Africa

St Lucia is one of the largest estuarine systems in Africa, and attracts thousands of anglers each year. Catchcard data from the National Marine Linefish System for the years 1986–1999 were analysed to determine catch composition, catch per unit effort (cpue) and seasonality of catches by recreational anglers. Because not all anglers completed catch cards, estimates of total catch were made using additional data on the number of private boat outings, the number of boat trailers at boat slipways and the number of boats recorded entering the campsite gates during 1992 and 1993. In all, 27 fish families, constituting 55 species, were recorded by recreational anglers. Dusky kob Argyrosomus japonicus, spotted grunter Pomadasys commersonnii, perch Acanthopagrus berda, Natal stumpnose Rhabdosargus sarba, springer Elops machnata and mini-kob Johnius dorsalis were the most prominent species caught in terms of numbers and mass. Catch rates expressed numerically (fish angler−1 h−1) peaked during the summer and early winter. However, in terms of mass, catch rates peaked during late winter and spring, when there were increased landings of large dusky kob. Fluctuations in cpue were linked to salinity and estuary mouth conditions (i.e. mouth closure). Despite annual fluctuations in cpue, regression analysis revealed an overall downward trend for the dominant species (dusky kob and spotted grunter) and a gradual increase for stumpnose, perch and springer, but with the exception of stumpnose, these trends were not significant. Socio-economic aspects of the fishery were also investigated by conducting an independent boat-angler survey. The value of the recreational fishery, in terms of accommodation and direct angler expenditure, was estimated to be in the region of R9 million during 1992. Angler attitudes towards fishing regulations were positive and anglers generally had a good knowledge of the regulations for target species. Based on this assessment, a number of suggestions are made regarding the future management of the recreational fishery at St Lucia.

OVERLAND DISPERSAL OF AQUATIC INVASIVE SPECIES: A RISK ASSESSMENT OF TRANSIENT RECREATIONAL BOATING

Predictions of the geographic spread of introduced species are often limited by a lack of data on their mechanisms of dispersal. We interviewed boaters and inspected boating equipment at public boat launches on Lake St. Clair (Michigan, USA) to assess the potential for the zebra mussel, an invasive bivalve, to be dispersed overland to inland waters by transient recreational boating activities. Several mechanisms associated with recreational boating were found to be capable of transporting either larval or adult life stages. Larvae were found in all forms of water carried by boats (i.e., in live wells, bilges, bait buckets, and engines) but were estimated to be 40–100× more abundant in live wells than other locations. Dilution in receiving waters should, however, greatly reduce the risk of establishing new populations by the introduction of larvae. Contrary to common belief, mussel dispersal from these boat launches did not occur by direct attachment to transient boats. Rather, adult and juvenile mussels were transported primarily on macrophytes entangled on boat trailers and, less frequently, on anchors (5.3% and 0.9% of departing boats, respectively). Combining these data with estimates of survival in air and reported boater destinations, we predict that a maximum of 0.12% of the trailered boats departing these access sites delivered live adult mussels to inland waters solely by transport on entangled macrophytes. While this is a small probability, high levels of vector activity resulted in a prediction of a total of 170 dispersal events to inland waters within the summer season from the primary boat launch studied. Many other potential vectors remain to be assessed, but the dispersal of zebra mussels by trailered boats, particularly by “piggybacking” on macrophytes entangled on the trailers, must be controlled in order to limit further range expansion of the zebra mussel within North America.

An Electrofishing Raft for Sampling Intermediate-Size Waters with Restricted Boat Access

Little information is readily available to fishery scientists regarding the design and construction of electrofishing rafts. I have modified some of the customary characteristics of oar-powered electrofishing rafts to create a raft that is powered by an outboard motor, is relatively light for easier transport to and from the stream, and provides easier passage through shallow waters. This raft design resulted in more effective sampling of smallmouth bass Micropterus dolomieu by allowing us to sample sections along a creek that were inaccessible to traditional electrofishing rafts and boats, which typically are launched from a boat trailer backed into the water. In addition, this design provided greater mobility within sampling sections, ensuring that all habitats were sampled.

A Study of the Performance and Stability of Articulated Towing Vehicle and Boat Trailer Combinations

SUMMARYIn an attempt to understand the cause of a recent boat trailer accident, a study of the performance and stability characteristics of articulated towing vehicle and boat trailer combinations was performed. The performance study (braking, acceleration and climbing and steady state handling) was conducted by employing various models and criteria. The stability characteristics of the configuration were investigated by means of a three degree-of-freedom, linearized mathematical model. The propensity for trailer roll-over during evasive manoeuvres was studied by using frequency response results from the 3DOF model to obtain trailer roll angle and tyre vertical reaction forces. It was found that boat trailer configurations could experience various types of instabilities of which the divergence and the snaking (fishtailing) instability are the most important. The instabilities could be caused by a host of factors such as too heavy a trailer, its mass centre in the wrong position, too long an overhang for the tow hitch or too high a vehicle speed. The divergence or the snaking instability could appear at a certain vehicle speed and it would initially be fairly mild and probably controllable but as vehicle speed is increased, the inherent severity of the instability would increase. A driver should hence not attempt to accelerate out of an instability. It was further found that heavy boat trailers are prone to roll-over during manoeuvring at high speeds. The analysis of the UCT boat trailer accident revealed that it was caused by a snaking instability which could not be controlled and which eventually led to trailer and vehicle roll-over. The vehicle combination was inherently unstable at speeds in excess of about 115 km/h due to the trailer being too heavy for its towing vehicle. The trailer roll-over threshold was also unacceptably low at these speeds. Striving to improve the safety of boat trailer configurations, it is recommended that available mechanisms which suppress snaking, or fifth wheel connectors, be used. As a byproduct of the current investigation, a mass-spring-damper system, with vibrational characteristics similar to that of a sustained snaking motion, is proposed.