The appended story is a great example of sustainability science. Ed is a bioacoustician who found a way to understand why manatees were getting hit by so many boats. Then he devised a technological solution: an alarm sound beamed out in front of a boat.
While I’m curious to know how he plans to work with managers and boat owners to install the devices, he already deserves accolades for setting a good example. I hope that Beam Reach can make similar strides in not only identifying risks to species of concern in the Pacific Northwest, but using technology and partnerships to reduce the risks. It’s telling that Ed has been grappling with the collision issue for 17 years!
Acoustic Phenomena Explain Why Boats And Animals Collide
Researchers at Florida Atlantic University have laid the groundwork
for a sensory explanation for why manatees and other animals are hit
repeatedly by boats. Last year, 73 manatees were killed by boats in
Florida’s bays and inland waterways. Marine authorities have
responded to deaths from boat collisions by imposing low speed
limits on boats.
In spite of manatee protection policies that have been in effect for
nearly two decades to slow down boats passing through manatee-
protection habitats, the number of injuries and deaths associated
with collisions has increased and reached record highs.
In an effort to reduce manatee deaths and injuries from boats, Dr.
Edmund Gerstein, director of marine mammal research and behavior in
FAU’s Charles E. Schmidt College of Science, set out in 1991 to
investigate what might be the underlying cause for these collisions.
Gerstein disagreed with the unsubstantiated assumptions, which
wildlife officials had relied upon, that manatees could hear boats,
but they were just too slow and could not learn to avoid boats.
“Manatees have the cognitive prowess to learn and remember as well
as dolphins and killer whales,” said Gerstein. “Furthermore, when
startled or frightened, manatees explode with a burst of power and
can reach swimming speeds of up to 6.4 meters per second in an
instant.”
Given that manatees have the cognitive ability to recognize danger
and the physical prowess to evade boats, Gerstein sought to explore
the answers to some simple questions. “After a manatee has been hit
more than once (some have been hit up to 50 different times) why
doesn’t the animal learn to get out of the way?” “Is it possible
that manatees are not aware or cannot hear the sounds of an
approaching boat?”
Gerstein and his colleagues conducted rigorous, controlled
underwater psychoacoustic (audiometric) studies to understand what
sounds manatees can hear in their environment. After a comprehensive
series of hearing studies, his research revealed that manatees
cannot hear the dominant low frequency sounds of boats and that
those sounds do not transmit well in shallow water. Furthermore,
ambient noise in manatee habitats can conceivably mask the
perception of many kinds of signals. Unlike dolphins, which can use
active sonar to navigate and detect objects in the environment,
manatees are passive listeners restricted to listening to their
auditory landscape.
“It is ironic that slow speed zones result in quieter and lower
frequency sounds which manatees can’t hear or locate in Florida’s
murky waters,” said Gerstein. “Slow speed zones make sense in clear
water where the boater and the manatee can see each other and
therefore actively avoid encounters. However, in turbid waters where
there is no visibility, slow speeds actually exacerbate the risks of
collisions by making these boats inaudible to manatees and
increasing the time it takes for a boat to now travel through
manatee habitats thereby increasing the risk and opportunities for
collisions to occur.”
With these issues in mind, Gerstein and his colleagues developed an
acoustic alerting device specifically tailored to exploit the
manatees’ hearing ability. The environmentally friendly device is
narrowly focused in front of the boat so that only manatees in its
direct path are alerted.
“The alarm emits a high-frequency signal which isn’t loud, doesn’t
scare or harm manatees and doesn’t disturb the marine environment,”
said Gerstein.
Gerstein has been testing this alarm in a NASA wildlife refuge where
controlled studies are possible. He has reported that 100 percent of
the controlled approaches toward manatees by a boat with the alarm
have resulted in the manatees avoiding the boat up to 30 yards away.
Without this alarm, only three percent of the manatees approached by
the same boat moved to avoid the boat.
Manatees aren’t the only animals that collide with boats. Other
passive-listening marine mammals, including great whales, are
vulnerable to collisions when near the surface, where the risk of
collisions with ships and boats is greatest or in shallow water.
Gerstein and his colleagues are using the findings from their
studies to help understand and reduce collisions in the open seas
where great whales are regularly injured and often killed by large
ships.
Source: Florida Atlantic University.
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As multiple agents in Western Washington begin the process of harnessing the tidal currents of the Salish Sea for generating electricity, it’s worth a close examination of what’s been learned by a pioneering tidal turbine project associated with the Race Rocks Ecological Reserve/Marine Protected Area. Through a partnership between Pearson College of the Pacific (288 students from 28 countries study International Baccelaureate) and Clean Current Power Systems (Vancouver, Canada), a project was initiated to provide renewable energy to the marine station and lighthouse.
Today, a tidal and solar power system has replaced the twin 15kW diesel generators that provided electrical power (and noise, air pollution, environmental risks) during most of the 20th century and much of the history of the Race Rocks reserve (established in 1980). I assume wind was judged inappropriate because so many sea birds nest and rest on the Rocks. I’m still just learning about the details, but wanted to share some notes and frame-grabs I took while watching a nice overview video of the Race Rocks tidal power project.
My overall impression is the turbine is big. Approximately 4m in diameter, the ~65kW turbine is designed to be scaled up to 1MW (presumably for future commercialization by CCPS). The forces exerted on the support column during the maximum 3.35 m/s tidal flows must be tremendous. A cool innovation I didn’t anticipate is that the blades are designed to turn in current from opposite directions. This means that the whole turbine assembly doesn’t have to rotate on the support column (like wind turbines do).
It’s hard to find measurements or engineering data on the blade rotation rate. Quoting from generic references about tidal turbines on the EIA page, “The blades themselves rotate quite slowly relative to hydroelectric and wind turbines, namely a few revolutions per minute depending on current speed, blade curvature and size but always to maintain a blade tip speed of less than 7m/s (when cavitation is likely to occur)” and typical rotation rates are “10-20 rpm.” For a blade radius of 2m, the tip velocity would be ~4m/s at 20rpm and ~2m/s at 10rpm. Given the arrangement of guided vanes I certainly wouldn’t want to swim through it at those rotation rates… but maybe a fish would do alright?
Funding for the project has come from Encana (natural gas and oil company’s Environmental Innovation Fund) and Sustainable Development Technology Canada (non-profit foundation created by Canadian government; Vicky Sharpe).
Chronology:
- Late 2005: preparatory (concrete) work on island for cable route and battery storage
- Jul 2006: Drilling complete (after 3 weeks), piling installation continues
- Sep 2006: Installation of turbine; hydraulic and electrical performance testing begins
- Dec 2006: Testing complete; cables connected to shore storage; Summary Report on Environmental Monitoring final draft submitted
- Apr 2007: Turbine raised to repair bearings
- Oct 2008: New turbine with stainless steel bearings, lubrication system, and reinforced augmenter duct.
Artists depiction of installed turbine
Technical details (these are surprisingly hard to find… values to be filled in are in italic):
- located ~100m from Island, ~15m depth, ~20m of water
- The top of the turbine is at a mean depth of 10m, or ~5m below MLLW; thus the whole assembly reaches about 10m off the seafloor.
- post diameter?
- turbine and funnel dimensions? (~3m diameter, but not sure if that’s augmenter or blades)
- power and voltage (what function of current speed?)
Diver guiding generator unit onto post
The generator sans cowling
Clean Current Power Systems staff interviewed in video
- Russel Stothers
- Glen Darou
- Virgil Young (aerospace)
- Chris Gora
Pearson College staff interviewed in video
- Gary Fletcher
- Dave Skilling
Other projects to keep an eye on:
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One of the grandest gestures we humans in Western Washington can make for endangered orcas and salmon is to finally remove the Elwha dams. The result would be a wonderful experiment in salmon restoration, as well as sediment dynamics.
I remember thinking that the removal was just a couple years away when I lived in Port Angeles for a couple months in 2002. For a LONG while we’ve all been thinking that the Elwha dam removal would be imminent.
I also imagined it would be more or less unprecedented. Yet, today I learned that our neighbors in Oregon have set a remarkably good precedent by breaching the Marmot Dam on the Sandy River, a tributary of the lower Columbia near Portland. This video of the river removing the dam in a single day should give us all hope in the current plan (sic) to let the Elwah sediment be transported naturally by the river.
How shall we help catalyze similar progress in Washington?
Thanks to the latest edition of Wild Salmon & Steelhead News for spreading the good news.
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It was just announced that the oldest southern resident killer whale is believed to have died this year. Lummi (K-7) lived to be about 98 years old and was last seen by Brad Hansen of NOAA/NWFSC on December 23rd. As the Center for Whale Research has surveyed all of K pod multiple times this spring, they are now confident that K-7 died this winter or spring.
The full article in the San Juan Journal got me wondering what Lummi heard in her lifetime. How much did the Puget Soundscape change since her birth in ~1910? The old matriarchs of the other pods, Granny (J-2, born ~1911) and Ocean Sun (L-25, born ~1928), also experienced the rise in anthropogenic noise in the oceans. Born at the end of the age of sail, they listened through two world wars, and persist during the crescendo of global shipping in the era of peak oil. I wonder if they were hard of hearing in their old age!
Steam engines were becoming more prominent than sail power around 1850-1900. The steam turbine was patented in 1897 and was initially used to power higher-speed ships. The diesel engine was patented in 1892 and began being used in vessels, including the Danish freighter Selandia in 1903. The current wikipedia entry for ship says that “Transport of people and cargo on sailing ships continued until the 1920’s.” So, it was a time of transition for marine propulsion systems, and therefore for underwater noise.
Locally, it’s clear that many fishing vessels were becoming motorized about the time that Lummi and Granny were born. An article about the refurbishment of an old halibut schooner by the algal energy company Blue Marble, states that their vessel (the Lituya, re-named the Blue Marble) was “one of the 150 or so motorized halibut schooners built between 1910 and 1932 to work the northern waters off Alaska and Bristol Bay — resting during the off-season in the calm waters of Seattle’s Fisherman’s Terminal.” I assume the same was happening with shipping traffic that transited the Strait of Juan de Fuca…
A quick search isn’t turning up a synopsis of shipping traffic in the Salish Sea over the last century or so. I’ll have to resolve to look for publications that document number and types of ships in Puget Sound historically. It seems my best bet may be to visit the research library associated with the Museum of history and industry. Does the Coast Guard or the Ports keep track of how many of each vessel type have come/gone? What about on the Canadian side of the border? Can we separate traffic transiting south of Vancouver Island with ships transiting the north side?
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I just read a story about a band that tours and amplifies under bicycle power alone. The technology they use could jump start an idea spawned during dinnertime discussions during past Beam Reach programs: mounting two bikes on the foredeck for power generation and exercise during the sea component. A nice twist would be having a couple nice, inspirational, bikes for Beam Reach students to use while on land. In homage to our bioacoustic spin, we could even outfit them with bike sound systems!
The fellow who designed Ginger Ninja’s system offers a variety of pedal power generator (PPD) products. Dante’s Do-It-Yourself predilections will resonate with some of Beam Reach’s core staff (Val Veirs, the tinkerer, specifically). It looks like a basic system can be purchased for about $1000. A crux for our application will be ensuring the system can endure the salt spray and precipitation of a catamaran’s foredeck. Another key issue will be whether the power is pushed into the house 12V battery or directly into the pedaller’s laptop…
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Thanks to Lindsay Delp (081) who just sent me a Discovery Channel article about the fluid mechanical efficiency of cetacean fins and flukes. It turns out (ha!) that wind turbines can be made more efficient by roughening the leading edge of the blades. The idea was inspired by studying the bumpy fins of humpback whales.
Seems like a nice next step (alluded to in the article) would be for the Beam Reach boats to substitute robotic flukes for the propellers! I’ll bet the resultant propulsion would be not only more efficient, but also more quiet underwater. Perhaps some day the whole whale watching fleet will be using different flukes, optimized for making Zodiacs porpoise and deep-keeled boats thrust silently along at 5 knots?
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It is disconcerting to me that J pod did not re-visit the west side of San Juan Island during the first two-week research cruise of the spring Beam Reach program. I joined the ship last Thursday fully expecting our fish tagging exercise to be interrupted by the returning southern residents. There was even a tantalizing missive from the respective American and Canadian killer whale God-fathers (from Ken Balcomb with allusions to John Ford) the previous day:
“Thursday, 1 May 2008 @ 13:41 …somewhere between here and Nanaimo there are 12-15 other whales that were heading south past John Ford’s house at sunset last night. It is about an 18 hour trip typically from there, so we could see whales any moment.”
But we were off Lime Kiln on Thursday and Friday and heard nothing but lingcod depth measurements. And so I returned to Seattle and listened fervently through the weekend — Port Townsend in one ear, Lime Kiln or OrcaSound in the other. I heard a lot of ships and noted that something seems to be beating the PT hydrophone during peak current flow, but there were no familiar calls or clicks.
Thus, I’m up late re-visiting my previous analysis of the historical sighting data. The general pattern is that there aren’t many days when southern residents are sighted (or heard) in Haro Strait during March, but the sightings per month steadily increase from April through June.
We designed the spring Beam Reach curriculum around these data which suggest that there is high likelihood of getting some preliminary data from J pod during the final two weeks of April. Analysis of the archives confirms that there are typically more sightings at the end of April than during the beginning.
Of course, our diligent (and patient!) students are now back on land analyzing simulated data sets so they’ll be ready for the arrival of J pod in May. We’re now about a week into May and J pod hasn’t been definitively sighted in the Salish Sea for nearly a month. When last seen on April 8th at 2pm, they were heading southwestward from Hein Bank into the Strait of Juan de Fuca, gateway to the Northeast Pacific.
Who else will be worried if they don’t return by this Thursday? The trend in sightings per month is hinting that 2008 is shaping up to be an unusual year. While March sightings were about average, April sightings were the lowest observed in the last 7 years. (There may be biases in these values, but if anything the sighting effort was less in the past, so older values are expected to be relatively low — not high!) Will May set a record low as well?
All this has me wondering what is going on out there. Has something appalling happened, akin to the surreptitious killing of California and Stellar sea lions in the Columbia River on Sunday? Or is there a problem with the fish that the residents prefer to eat: salmon, and Chinook in particular? We know that the California runs have essentially failed this year, with the commercial Chinook fishery mostly closed along the West Coast for the first time in more than 40 years.
Surprisingly, it’s proving very difficult (even for an oceanographer like me) to get a coherent overview of what marine fish are around Puget Sound. The data I’ve found and ways Beam Reach is helping to fill the gaps are the topic of my next post…
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Row boats have graced the docks of the Friday Harbor Labs for many decades. To me, they have always offered a heart-warming counterpoint to the academic intensity of the Labs. After a day spent inside studying the oceans’ creatures with pipettes, microscopes, and computers, the row boat fleet beckons to the simple scientist, offering a chance to reconnect physically with the sea, marine history, and maritime language. An added appeal of the row boats is the possibility of making it to town or around the Harbor under your own power.
This spring, thanks to the good fortune and generosity of Beam Reach instructor Jason Wood, a wind-powered vessel supplemented the maritime scene down on the FHL docks. Jason inherited a sailing dinghy this winter from a neighbor on the west side of the Island. With a little rust-busting assistance from instructor Val Veirs, the mighty (little) Ciprid was deployed for the first time this spring as a sail training vessel.
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So, Beam Reach students now have two ways to experience sustainable transport technologies and to train for navigating our 42′ sailing research vessel, the Gato Verde. I’m pleased these intrepid vessels are available to strengthen our curriculum early in each program.
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I think a tradition was born last Friday, July 28. Sailing, learning, and fun were had by all at our “open boat†event. Captain Todd Shuster gave tours and sails on his recently re-powered catamaran. Now the west coast’s only biodiesel-electric charter sailing vessel. We listened to an underwater hydrophone (wow, it can be loud under water!), watched video footage from the Beam Reach program last fall, heard recorded killer whale sounds, and we all met interesting people. Here are some photos from the event.
Everyone marveled at the near silence of the Gato Verde’s electric motors. In fact, the only real reason you knew the motors were on was because we were moving, but the sails were down. There was wind so we were also treated to sailing under wind power alone.
Beam Reach alums Celia Barrosso and Laura Christoferson were on hand to tell people what it was like for them to study killer whales for ten weeks — five of which were at sea aboard the Gato Verde. For both it remains a highlight of their lives and continues to provide inspiration and guidance to their careers.
We’d love to hear your thoughts on the day. Post a comment to this article so everyone can learn from you and hopefully be inspired to attend next year’s event.
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Authored by: Captain Todd Shuster and Dr. Scott Veirs
A new type of boat will study the orcas and their environment this fall. The Gato Verde is a 13-meter (42-foot) sailing catamaran that recently became the first biodiesel-electric charter vessel on the West Coast. Last winter, dual 27-horsepower diesel engines were replaced with two electric motors, extra batteries, and a 14-KW genset burning biodiesel. The re-powered Gato Verde will serve ecotourists through Gato Verde Adventure Sailing out of Bellingham, Washington, this summer and the Beam Reach marine science and sustainability school this fall when students will study orcas and acoustics.
We’re confident that ecotourists will appreciate the changes. Sea trials indicate that propulsion noise and vibration is dramatically reduced in the cockpit and hulls. Diesel fumes and exhaust are gone and the increased propeller pitch and extra blade have enhanced maneuverability in close quarters. The total mass of the propulsion and power system increased only ~100-kg, and distributing the extra batteries in the bows re-balanced the load and improved hull performance.
Teachers in boat-based programs like Beam Reach and researchers who study orca acoustics will also value the quieter system. Class discussions in the cockpit will benefit from the ability to transit quietly under electric power. Fumes and exhaust from the biodiesel genset will be less distracting than fumes from petroleum diesel and its combustion. Acoustic observations will be much easier to make while moving under power; last fall, extended, continuous recordings were only acquired when the wind and currents allowed us to sail parallel to the traveling orcas.
Noise reduction in engine compartment and underwater
Lynch motor mounted on the saildrive.
The modifications significantly decreased the in-air sound pressure levels (SPL) in the engine compartments. Using a sound meter from Radio Shack held horizontally in different parts of the port engine compartment, we measured sound pressure levels before and after the re-powering of Gato Verde. In comparing the conventional diesel propulsion system with the electric one (powered by batteries only, no generator), sound pressure levels (C-averaging setting) were reduced at all measurment locations:
| Sound pressure level in decibels (dB) |
| |
upper compartment |
lower compartment |
| |
base |
top |
loudest point |
| Yanmar diesels |
94 |
105 |
124 |
| Electric only |
83 |
89 |
97 |
| Difference |
-11 |
-16 |
-27 |
For reference, a -6 dB shift is SPL is generally perceived as a halving of loudness. All measurements were made on the horizontal centerline of the compartments, except the loudest point measurements which were at (~1 cm from) the the air intake on the diesel engines and at the outboard base of the sail drive in the hybrid system.Preliminary, qualitative observations indicate that underwater propulsion noise is reduced, as well. Quantification of this improvement will have to await re-occupation this fall of the site where the diesel engine noise was measured. If the noise reduction is substantial and the economic benefits are made clear, then Gato Verde may provide other commercial and private vessels with an inspiring example of technology that can reduce underwater noise in orca habitat.
Engineering and performance
Captain Todd holding a Lynch motor.
Gato Verde is a 1995 Fountaine Pajot Venezia 42 Catamara (LOA 42’, LWL 40’+, beam 23’, dry weight 19000lbs, full capacity weight 23500lbs). The previous propulsion system consisted of dual Yanmar 27hp (3gm30) engines with saildrives. Each Yanmar was replaced with an “off-the-shelf†Thoosa 9000 system. The muscle of each electric system is a Lynch motor and the brains are a 4 quadrant (regen) Navitas controller. There is a Link 10 Battery monitor on each system. Each of the two battery packs consist of four 12V Group 31 AGM batteries providing 105AH @ 48V to each motor. The motors are mounted to the old Yanmar SD20 sail drives and are turning new 3 blade 17â€X15†props. The saildrive reduction is 2.6:1 and was used without modification by mounting the motor to the existing power input shaft with a custom fitting.
The new biodiesel-electric-sail power system allows Gato Verde to match (or better) previous motoring performance while decreasing fuel & lubricating oil consumption by up to 50%. Additionally, the battery pack enables Gato Verde to motor silently for up to 3 hours. When extended motoring is required, the on-board biodiesel generator will provide enough electricity to power the electric motors continously. Based on the volume of the fuel tank, we estimate an endurance of 125 hours/tank or about 625 miles. Finally, the propulsion motors will be able to re-charge the battery bank when under sail by letting the props spin turning the motors into generators.
The Thoosa 9000W system was chosen for several reasons. The system is simple and uses an efficient 4-quadrant regeneration controller. Given the risks of early adoption, it was comforting that the Thoosa system can be upgraded with increased voltage if extra power is ever needed. It was convenient that the Thoosa importer (NGC Marine in Racine, WI) could provide the two systems within the desired installation window. Finally, Hank at NGC Marine provided compelling performance projections (16×16 propeller; 8 batteries [Group 31 AGM] totaling 210AH) with and without the gen-set running:
| Without gen-set |
With 12KW DC gen-set |
| speed (knots) |
Endurance (min) |
speed (knots) |
% battery assist |
| 4.5 |
130 |
7.1 |
0% |
| 5.0 |
095 |
|
|
| 6.0 |
050 |
8.1 |
100% |
For comparison, the Yanmar engines propelled Gato Verde at 7.4 knots in calm conditions @ 3400 RPM.The bio/diesel gen-set consists of an eCycle DC generator built on a 3-cylinder 23 HP Kubota D902. The water-cooled motor/generator puts out over 12KW @ 58V DC. The buck-boost regulated system is more expensive than diode charge regulation, but it will put out the full charging voltage for the 48V battery pack no matter the RPM of the engine. Changing RPM changes current, not voltage. Thus, the generator speed can be reduced or increased to provide the exact amount of energy needed for any given conditions. For battery charging or boosting, the generator can be run at low speeds using less fuel and creating less noise. In a situation where maximum power is needed the generator speed can be increased to meet the demand.
Sea trials were conducted on April 6, 2006. The following performance data was taken in calm conditions the running times are estimates with around 20% reserve:
(Note: the last 2 data points are unevenly plotted in the range.) Gato Verde’s first charter with the electric drive system was a great success. Since the DC generator parts had still not arrived and a small gasoline AC generator was used for battery charging. The regeneration under sail worked whenever we were sailing over 6.4 knots. We don’t have detailed data on speed vs. current output yet but measured as much as 11 amps at one point when our boat speed was approximately 7.8 knots. We’re looking forward to getting out in a good blow to do some serious data collection.
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