Reducing Fuel Use in the Tropical Shrimp Fishery with Cambered Doors, Sapphire ® Webbing, and Skewed Propellers 1

1. Reducing Fuel Use in the Tropical Shrimp Fishery with Cambered Doors, Sapphire® Webbing, and Skewed Propellers1 Prepared by Michael G. Haby2 & Gary L. Graham2 Narrated by Nathan P. Kemper3 1. This work was supported with funds provided by: (a) the U.S. Department of Agriculture to the Texas AgriLife Extension Service, part of the Texas A&M University System (award number 2005-48605-03347) and (b) the Texas Energy Conservation Office, headquartered within the State of Texas Comptroller’s Office, to the Sea Grant College Program at Texas A&M University (award number 0000421118). Texas AgriLife Extension Service / Sea Grant College Program / Texas A&M University Trade Adjustment Assistance Coordinator, Southern Risk Management Education Center, University of Arkansas

2. An Overview of The Presentation • Introduction • Why address ways to save fuel when the industry is experiencing record catch rates? • A review of historical fuel-saving efforts undertaken by shrimp fishermen and the Sea Grant College Program. • A look at the topics covered in this presentation • Adaptation & testing of trawl gear new to the shrimp fishery. • Comments about a preliminary propeller-comparison study. • Measuring and comparing economic results of new trawl and propeller gear. • Next steps for the Southeastern shrimp-trawl fishery...

3. Catch rates are at record levels so why address fuel savings? Things change ... • Before 2001 ... • Low-cost inputs were used to harvest high-dollar shrimp. • In all but “banner” years catching enough shrimp generally limited profitability. • The formula for success focused on creating the capacity to catch more shrimp. This meant investing in larger more powerful vessels that could pull larger nets faster, and stay offshore longer. • Since 2001 ... • Skyrocketing catch rates, but high-cost inputs are used to harvest lower-valued product. • Profitability requires operators to reduce avoidable costs.

4. Historical Review of Fuel EfficiencyEfforts in the Shrimp-trawl Fishery • Post WWII − operators installed military-surplus, diesel engines. • In the 50s − industry began using double rigs. • In the 60s − cotton webbing was replaced by nylon. • In the 70s − offshore trawlers converted to quad rigs. • In the 70s & 80s − many vessels added propeller nozzles. • In 89 & 90 − nets made from high-tensile-strength, small-diameter fibers demonstrated fuel savings over nylon-based webbing. • In the 90s − some operators switched to more modern propellers.

5. Trawl Gear Track: Comparing the Efficiency of Different Trawl Doors and Webbing

6. A Cambered Door Uses the Same Principle of Pressure Difference as an Airplane Wing As the door (or plane) travels forward, less water (or air) pressure on the curved surface allows the door (or plane) to pull outward (or lift). Outward pull is created by a pressure difference; not resistance generated with a large angle of attack using a four-chain bridle system.

7. Hydrodynamics Applied to Door Design

8. Pioneers Who “Found A Better Way” Clockwise from top right: Patrick Riley, General Mgr. –Western Seafood Captain Manuel Calderón – Western Seafood Captain Louis Stephenson – F/V Master Brandon In 2008 each of these men received the NMFS Sustainable Fisheries Leadership Award

9. Initial Sea Trials (“Proof of Concept”) • Work began April 2005 aboard the F/V Isabel Maier • Baseline: • Caterpillar® 3412 (500 hp) • Kort nozzle with skewed Rice wheel • 4 – 47½ ft. two-seam trawls • Spectra® webbing • 9' x 40" wooden doors (2.79 m²)[9' x (40" ÷ 12"/ft.) x (1m² ÷ 10.76 ft.²)] • Initial findings: • Experienced difficulty in setting. • Doors laid in outward position. • After numerous tows, got gear to bottom & the nets to open. • Sled (“dummy door”) sank faster than trawl doors.

10. Initial Trials Showed Proof of Concept, and Identified Several Required Changes Trial and error for choosing right door size Attaching the door to the towing cable was problematic. Shoe on the bottom of the oval door needed to be modified. Quad rig sled needed to be modified.

11. Trawl Gear Modifications from Sea Trials (1) • Rethinking the required size of cambered trawl doors was the first modification: • Cambered doors generated tremendous spreading power. • Initially evaluated 2.1m2 cambered doors in place of the 2.79m2flat doors (108" x 40"). • Each door weighed 330 to 616 lb. with weight added.

12. New Doors are Fifty Percent SmallerThan Traditional Wooden Ones • Trial and error demonstrated the 1.4m2 cambered doors properly opened 2 – 47½ ft. two-seam nets • Compared to the area of the 108" x 40" traditional flat door (2.79 m2), the area of the 1.4m2 cambered door is 50 percent smaller.

13. Holes in the Brail Connect TrawlDoors to the Towing Cables Brail shown with different attachment points ... These points control the angle of attack

14. Trawl Gear Modifications from Sea Trials (2) • Connecting trawl doors to the towing cables • To create the angle of attack with flat doors, a 4-chain bridle system is required. The 4-chain bridle establishes both the angle of attack and the amount of “cut” in the door. • This 4-chain approach does not work with the vented, cambered doors. • Initially, cambered doors had just one connection point on the brail. This is the most common connection method worldwide. • Ultimately the new doors were connected with 2-chain bridles, one at the brail, and the other at the aft, bottom position of the door.

15. Two-chain Bridle Connected toa Vented, Cambered Door

16. Bridle Configuration for 1.4m2 Door

17. View of Vented, Cambered Door Showing Two-chain Bridle & Angle of Attack

18. Trawl Gear Modifications from Sea Trials (3) • “Stock” doors with curved shoes resulted in a 19% shrimp loss because of elevated lead line and tickler chain. • Once curved “shoes” were replaced with flat ones, the lead line and tickler chain attachment points were lowered, & shrimp loss ended. Padeye welded to the back of the shoe is the second connection point “After-market”, Flat Shoe “Curved” Shoe

19. Net Attachment Positions for 1.4m2 Door

20. Headrope Attachment • Several horizontal holes on the back of the doors connect the trawl. • Moving headrope & footrope to an adjacent hole alters the angle of attack by about 2 ½ degrees. • Adjustments on the aft end of the door work opposite to the towing points on the brail. • Connecting the net in the forward-most point increases angle of attack. • Attaching the net further aft decreases angle of attack.

21. Trawl Gear Modifications from Sea Trials (4) • The traditional sled sank faster than the cambered trawl doors. • New sled designs slowed descent to the sea floor: • Original modification (left) incorporated a buoyancy tank. • Subsequent modification (right) used lower-cost, flat-bar stock with a much wider shoe which “skied” to the bottom.

22. Two Views of the Buoyancy-tank Sled in a Double-rigged Trawl System

23. Essential Periodic Maintenance Ensures Continuous Production Effectiveness Stress elongates towing holes in the doors! To keep the gear fishing correctly, the original diameter must be maintained. Friction can compromise shackles in a single cruise! Extra shackles should be aboard.

24. Double-rigged, Energy-conserving Trawl System Being Retrieved & Loaded

25. Meter had to be matched to the engine brand and horsepower The meter measured fuel consumption in gallons per hour, and indicated current consumption with a dial. Very basic design Worked well in most cases Fuel Flow Meter

26. Engine Performance & Fuel Comparison: Wooden vs. Vented, Cambered Doors

27. Three-week Cruise Aboard the Isabel Maier With Traditional & Experimental Gear • After all four modifications were completed, a production cruise was conducted between mid-April and early-May 2006. • During this cruise the first-ever performance information was collected during an actual fishing trip. • To assess shrimp production differences: • both gear types were fished simultaneously, • gear position was swapped after 15 good tows to control for side bias, • cambered doors generated a 2.6% shrimp gain, but it was not a statistically significant difference. • No shrimp loss was encountered with the cambered doors.

28. Intensive Technical Assistance Tim Adams – Bon Secour David Chauvin – Chauvin Juan Gaona – Brownsville Bobby Pendarvis – Irvington Tom Williams – Tarpon Springs Texas Energy Conservation Office Delbert Bull, Jr. – Sabine Pass Charles Burnell – Brownsville Manuel Calderón – Freeport Frank Lasseigne – Brownsville Louis Stephenson – Hitchcock Cooperative Research by Elite Producers • Areas Tested • The doors have been fished on all sides of the Gulf • Muddy, offshore substrate • Hard Florida bottom • Offshore and on the beach

29. Study Protocol for Evaluating New Gear • Each cooperator was asked to record fuel use and engine RPM across steps one, two, and four of a four-step procedure. • Step 1 – Baseline (current complement of nets and doors). • Step 2 – Sapphire® nets spread with traditional doors. • Step 3 – Side-by-side prod. equivalency (traditional vs. cambered). • Step 4 – Sapphire® nets spread with cambered doors. • Approach • Cooperators pre-selected a speed-over-ground towing rate and attempted to hold it across steps 1, 2, & 4 of the four-step protocol. • Each half hour the cooperator recorded: • Time of day • Actual speed-over-ground • Engine RPM • Fuel consumption (from the indicating fuel-flow meter) • “Current” sea conditions (With, Against, Across, Slack) • Eight 3½ hr. tows are required for steps 1,2, & 4. • 15 good tows per side are required for the prod. equivalency step.

30. Helping Cooperators Address the“Learning Curve” for Cambered Doors In more profitable times, most operators could experiment with the new doors & reach production equivalency. Today, such experimentation is economically impractical due to: an abbreviated production window & record prices – on the high side for fuel and on the low side for outputs. Two elite, consulting fishermen, Captain Louis Stephenson and Captain Manuel Calderón, have: helped the cadre of cooperators complete their 4-step protocols & sped conversion to this new gear.

31. South Atlantic Experiences withVented, Cambered Doors One smaller boat in South Carolina that exclusively fishes the beachhas been using the cambered doors for several years. The gear was tested for how well it handled very hard turns, and the doors maintained their spread. Using traditional gear this vessel burned 10½ – 11 gph. After switching to the cambered doors, fuel consumption dropped to 9 – 9½ gph; a reduction of 13 to 14 percent. In addition to the fuel savings, less drag with cambered gear enables this operator to fish against strong winter seas and currents. Others pulling traditional flat doors must trawl, pick up, run up-sea, and re-deploy in a following-sea. Much more fuel and time is used with the traditional gear in the stronger seas and heavier currents.

32. What About The Inshore Fleet? • Little work has been done inshore. • Greg Falkner in Louisiana did some early work that showed positive results.

33. High Aspect (taller than long) Vented Very Short Used worldwide ... But needs to be evaluated A Potential Door for Smaller Nets

34. Replacement Considerationsfor Cambered Doors (1) • Cambered doors should be roughly ½ as long as what you now pull, but net size, net style, and webbing material also influence door size. For example, 2 – 45’ nylon nets require 1.4m2 doors but that same nets made from Spectra® or Sapphire® can be spread with 1.1m2 doors. • Evaluation by elite fishermen suggest the following rules of thumb: • If you are pulling 2 – 40’ to 45’ nets, then use 1.1m2 doors • If you are pulling 2 – 45’ to 50’ nets, then use 1.4m2 doors • Sea trials of doors required to spread 2 – 50’ to 55’ nets are preliminary and suggest that 1.4m2 doors are marginal at the 2nd tow point. Sea trials of doors required to spread 2 – 55’ to 60’ nets have not taken place.

35. Replacement Considerationsfor Cambered Doors (2) • Remember ... The smaller the angle of attack, the less the resistance and the greater the fuel economy! • Therefore, choose the door size that allows your nets to spread fully when the doors are pulled from the most forward hole in the brail. This will ensure the smallest angle of attack. • Cost differences between 1.1m2 – 1.4m2 and 1.4m2– 1.6m2 doors are about $50 per door, a minor issue. When in doubt, choose the next larger size.

36. Sapphire® Fiber, Webbing, and Nets • Characteristics of Sapphire® used on our evaluations: • Small-diameter (2.1mm), high-tensile-strength material. • Fibers are braided, not twisted. • No dipping is ever required with Sapphire® webbing. • High-density polyethylene (HDPE) − recyclable. • Our work has shown that active vessels get more than 3 years use with braided Sapphire® webbing.

37. Why Sapphire® Webbing?? In 1990, Sea Grant did extensive work with Spectra®. Excellent results were achieved, and many boats converted to it. The original cost of Spectra® was $28.00/lb. As a component in personal body armor, military demand pushed the price to over $60.00/lb. at the time our cambered door project began. Sapphire® webbing cost $8.50/lb. and was chosen because of its durability and price. Other high-tensile-strength, small-diameter fibers are available which can reduce drag and generate fuel efficiency, but they are more costly than Sapphire®. Keep in mind that all of these new fibers weigh less than nylon, so you get more webbing per pound purchased.

38. Twine Size Advantages Early Spectra® evaluations used #11 which replaced #18 nylon. This reduced twine area of the entire trawl by about 23.5%. The Sapphire® used in the new study had a diameter of about 2.1mm − roughly equivalent to #15 nylon.

39. Saving Additional Fuel with Sapphire®Nets: Cooperators’ Results • Step two of the protocol quantified the proportional fuel saving attributable to Sapphire® nets spread with traditional doors. • Being braided instead of twisted appears to be an important contribution to fuel savings. • Sapphire®nets savedfuel! • Captain Tim Adams reported 1 gal./hr. savings. • Captain Manuel Calderón reported ½ to 1 gal./hr. savings. • Captain David Chauvin reported 1 gal./hr. savings. • Captain Louis Stephenson reported 1½ gal./hr. savings.

40. Performance Summary: Cambered Doors • The doors have been in continuous use since 2006, and shrimp production has not suffered! Some operators still resist. • Among our cooperator base, when help was requested, adjustment or production problems were quickly solved. • Doors are not difficult to use, but adjustment logic is different. • Doors are effective across all Southeastern shrimp fisheries (nearshore or offshore, muddy substrate or hard bottom, brown or white shrimp). Gear can handle sharp turns, etc. • Shackles and swivels need frequent replacement. Also, the diameter of towing points in the brail need to be maintained. • At very slow speed-over-ground rates (around2.2 kt.) questions arise about effectiveness.

41. Propeller Track: Comparing Efficiency of “Nozzled” Kaplan and Skewed Propellers

42. The Skewed Propeller … • Not the newest technology. The Rice Speed Wheel has been introduced since the skewed propeller was designed. • Some owners switched to the skewed propeller, but no comparative performance data were ever collected from fishermen for public use. • At industry’s suggestion, RPM and fuel consumption was compared between Kaplan-style and skewed propellers. • Kaplan-style data were collected in late summer & early fall. • Skewed data were collected in winter when seas are stronger/heavier, and currents are faster. • Therefore, the computed difference of 0.9 GPH savings (6.1%) with the skewed wheel is probably conservative!

43. Additional Fuel Savings Documented with Initial, Comparative Wheel Trials

44. Economic Results Track: Current Operating Conditions Facing U.S. Shrimp Fishermen • Significant reduction in operators and thus fishing effort between 2002 and 2006 has boosted catch rates. But … • Shrimp fishing is a fuel-intensive enterprise. • Producers have paid record prices for fuel while receiving historically-low prices for their shrimp which has squeezed margins to razor-thin levels. • Imports continue relatively unabated and • Short-term “shocks” have also affected local prices. • Since 2001, remaining operators’ main objective has been “to remain liquid enough to fish another day.” • “Non-essential” maintenance has been deferred.

45. Fuel: A Large, Growing Production Expense for Wild-harvested Shrimp • Between 1986 & 1997 the median offshore shrimp trawler used 66,101 gallons of diesel each year (TAMU Standardized Performance Analysis project). • In 1997 those 66,101 gallons cost $49,576 ($0.72/gal.) • In 2006 those 66,101 gallons cost $140,400 ($2.12/gal.) • In 2008 those 66,101 gallons cost $209,776 ($3.17/gal.) • In 2006, roughly 40% of the 2,666 permitted offshore trawlers remained idle due to high fuel costs & low ex-vessel prices. • In 2007, days fished across the Gulf in the 10 to30 fathom range had declined by 78% compared with the ’01 to ’03 base. • In 2008, roughly 20% of shrimp fishermen gulf-wide did not generate a trip ticket … they did not fish.

46. A Summary of Fuel Savings Reported Through Cooperative Research • Results from offshore cooperators indicate the new trawl gear generates immediate, significant fuel savings. • S&S Sales (fleet): 375 hp. pulling 4 – 42 ft. nets reduced fuel use by 28 to 39%. • Western Seafood (fleet): 500 hp. pulling 4 – 47½ ft. nets reduced fuel use by 28 to 33%. • F/V Mariah Jade: 600 hp. pulling 4 – 32 ft. nets reduced fuel use by 27%. • F/V Master Brandon: 500 hp. pulling 4 – 50 ft. 2-seam nets reduced fuel use by 20% inshore & 24% offshore.

47. Expected Range in Fuel Savings from Cooperative Research • Documented fuel savings ranged from 10% to 39%. Consider the “middle half” of that range. • The median fuel-savings value is 24%. • 25% above and below that mid-point we find a 28% savings and a 20% savings. • This “middle 50%” of fuel-savings values (20% – 28%) is the range in fuel-savings most offshore operators can expect!

48. Actual & Forecasted Nominal Industrial Price for No. 2 Diesel by All Sellers: 1994 – 2035

49. Long-run Outlook for Fuel (2010 – 2035) • From 2010 to 2035, forecasts suggest diesel prices will increase by about 15¢ per gallon each year. • About every seven years, the forecasted price will increase by roughly $1.00 per gallon. • This forecast only reflects trend … supply interruptions, additional regulations further limiting sulfur, etc. can dramatically influence actual prices. • Current diesel prices exceed the 2011 forecast by $1.00 per gallon! • Energy price changes will affect the cost of virtually all activities.

50. Cost-reducing Effects of Cambered Doors, HDPE Webbing, and Skewed Propellers • Cambered doors & small-diameter HDPE webbing drive production costs out of the shrimp-trawling enterprise. How? • Less drag (mostly from the doors) requires fewer RPM to reach speed-over-ground towing rates so GPH decreases. • Fewer RPM reduce engine-service hours per hr. operated. • Reduced fuel use extends time between overhauls. • The new trawl doors and HDPE webbing are longer lasting: • Wooden doors last 12 to 18 months but cambered steel doors last 7 to 8 years if maintained. • Nylon nets last 1 to 2 years but Sapphire® nets last 3 to 4+ years. HDPE nets do not require dipping –a huge savings!! • A skewed propeller can further reduce fuel consumption.