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Whitelaw & Pearson The Costs of Increasing a Basic Shrimp Vessel from 65 to 85 FEET A Case Study.
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Transcript of Whitelaw & Pearson The Costs of Increasing a Basic Shrimp Vessel from 65 to 85 FEET A Case Study.
Whitelaw & Pearson
The Costs of Increasing a Basic Shrimp Vessel from 65 to 85 FEET
A Case Study
Whitelaw & Pearson
The Task
To investigate the economic sense of increasing the length of vessels designed to prosecute the inshore fishery now being served by a fleet restricted to 65 feet LOA.
Whitelaw & Pearson
65 Feet And Growing
Whitelaw & Pearson
Trend Towards Increased Breadth
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
1975 1980 1985 1990 1995 2000
YEAR
LE
NG
TH
/ BR
EA
DT
H R
AT
IO
Whitelaw & Pearson
Forces Driving Increased Vessel Size
MULTI-SPECIES FISHINGQUALITY IMPROVEMENT THROUGH BOXING AND REFRIGERATED SEAWATERDECK AREA for HANDLING & PROCESSINGCREW ACCOMMODATION
Whitelaw & Pearson
Vessel Variations
A “TYPICAL” BOAT 65 x 24
INCREASED BREADTH 65 x 30
INCREASED L 75 x 27.5
INCREASED L 85 x 31
Whitelaw & Pearson
Vessel Variations
ASSUMED CONSTANTS
QUOTASOPERATIONAL SPEEDCREW SIZEBRIDGE AREA
VARIABLE WITH VESSEL SIZE
FISH HOLD CAPACITYDECK AREAACCOMMODATION AREA
Whitelaw & Pearson
Side Issues – Rules And Regulations
GROSS TONNAGELARGE vs. SMALL F.V. REGULATIONSMANNING REQUIREMENTSLIFE SAVING EQUIPMENTBILGE, BALLAST AND FIRE FIGHTINGSTRUCTURAL FIRE PROTECTION
Whitelaw & Pearson
Capital Cost Categories
BASIC HULL AND DECK STRUCTURETOPSIDES & OUTFITUNDERWATER EQUIPMENT (STEERING & PROPULSION)
MAIN PROULSION MACHINERYELECTRONICSFISHING GEAR & HYDRAULICSREFRIGERATION & RSW
Whitelaw & Pearson
CASE STUDY - Independent of Length
OUTFIT LEVELELECTRONICS PACKAGEAUXILIARY MACHINERYFISHING GEAR & HYDRAULICSREFRIGERATION
Whitelaw & Pearson
CASE STUDY - Principal Variables
HULL AND DECKS STRUCTURE
MAIN PROPULSION MACHINERY
PROPELLER AND SHAFTING
Whitelaw & Pearson
CASE STUDY - CAPITAL COST BREAKDOWN
TOPSIDES & OUTFITTING
43%
HYDRAULICS/ FISHING GEAR12%
PROP/ STEERING4%
REFRIGERATION2%
PROPULSION MACHINERY
12%
ELECTRONICS 5%
BASIC HULL AND DECKS
22%
Whitelaw & Pearson
CASE STUDY - Hull and Deck Structure
FRP (Fibre Reinforced Plastic) ConstructionAmerican Bureau of Shipping (ABS) Rules for Building and Classing Reinforced Plastic VesselsLaminate Weight the Basis for Cost Comparison
Whitelaw & Pearson
CASE STUDY - Capital Cost Comparison
COST CATEGORY 65 BASIS 65 75 85
BASIC HULL AND DECKS $292,875 $343,750 $348,219 $439,313
TOPSIDES & OUTFITTING $542,763 $687,500 $687,500 $687,500
ELECTRONICS $80,000 $80,000 $80,000 $80,000
PROPULSION MACHINERY
PROP/ STEERING
HYDRAULICS/ FISHING GEAR $186,300 $186,300 $186,300 $186,300
REFRIGERATION $30,000 $30,000 $30,000 $30,000
TOTAL CAPITAL COST (MILLIONS)
Whitelaw & Pearson
THE QUESTION OF POWER
THE BASIS:Determine the required installed power for each vessel
to meet the requirements of:10 knots free running speed and 6 tonnes of tow pull at 2.5 knots
Whitelaw & Pearson
The Resistance Prediction
Started by generating lines for the four vesselsPredicting resistance for specific vessels 65 x 24 represents where vessels are now75 and 85 vessels are based on this parent hull65 x 30 represents the trend of where design is going
Whitelaw & Pearson
The Resistance Prediction
No model tests were done The resistance prediction was based on a “standard series” of similar vesselsThe accuracy of the prediction depends on how “similar” the study vessels are to the series vesselsFortunately someone else has done work on short/fat vessels, or “Low L/B Vessels”
Whitelaw & Pearson
Vessel Parameters
Cb** LWL B T
(ft) (ft) (ft)
1.75 m Draft
65’ x 24’ (Gen) 0.380 0.454 61.385 24.000 5.741 2.558 4.180 3.751
2.0 m Draft
85’ x 31.385’ 0.333 0.441 80.051 31.385 6.562 2.551 4.783 4.018
75’ x 27.692’ 0.354 0.442 70.639 27.692 6.562 2.551 4.220 3.849
65’ x 30’ 0.379 0.515 61.713 30.000 6.562 2.057 4.572 3.262
2.25 m Draft
65’ x 24’ (Gen) 0.379 0.535 61.745 24.000 7.382 2.573 3.251 3.311
2.5 m Draft
85’ x 31.385’ 0.331 0.513 80.623 31.385 8.202 2.569 3.826 3.589
75’ x 27.692’ 0.351 0.515 71.666 27.692 8.202 2.588 3.376 3.464
65’ x 30’ 0.378 0.579 62.087 30.000 8.202 2.070 3.658 2.945
VesselFn @10 knots
L/B B/T L/1/3**
Whitelaw & Pearson
Series Parameters
Cb L/B B/T
0.447 - 0.631 2.60 - 3.98 2.81 - 4.23 3.01 - 5.30
L/1/3
We had a good basis for predicting the resistance of the 65 x 24, 75 x 27 and 85 x 31 foot vessels
Unfortunately no one has done vessels as “short” and “fat” as the 65 x 30 so these results are a bit suspect
Whitelaw & Pearson
Effective Power
0
50
100
150
200
250
300
350
400
450
500
2.0 4.0 6.0 8.0 10.0 12.0
Speed (knots)
Eff
ec
tiv
e P
ow
er
(kW
)
65 x 24 65 x 30 75 x 27.7 85 x 31.4
Whitelaw & Pearson
Summary PE at 10 knots
Effective power for all vessels is essentially the sameAs expected the longer vessels require proportionately less power for the same speedThe power for the 65 x 30 is probably under-predicted
PE
(HP)
65' x 24' 221
65 x 30 A 235
75' x 27.7' 227
85' x 31.4' 244
VESSEL
Whitelaw & Pearson
Summary PE at 10 knots
The power for the 65 x 30 is probably under-predicted
This was confirmed by Professor Friis based on recently completed model testsWe added a new vessel 65 x 30 A
PE
(HP)
65' x 24' 221
65 x 30 A 353
75' x 27.7' 227
85' x 31.4' 244
VESSEL
Whitelaw & Pearson
Propulsion
The effective power is simply the power required to push or pull the hull through the water at 10 knots That brings us to the propulsion calculations.
Whitelaw & Pearson
Free Running Performance
VESSEL PROP EFFICIENCY PD (HP) PB Brake Horsepower
65 x 24 0.594 399 420
65 x 30A 0.548 649 683
75 x 27.7 0.637 360 379
85 x 31.4 0.640 384 404
Whitelaw & Pearson
Towing Performance
Towline pull is a function of the prop, not the shipA bigger prop is better
VESSEL PROP EFFICIENCY PD (HP) PB Brake Horsepower
65 x 24 0.166 470 494
65 x 30A 0.166 470 494
75 x 27.7 0.193 409 430
85 x 31.4 0.202 388 408
Whitelaw & Pearson
Propulsion
The best combination of propeller pitch and RPM for free running is NOT the best for the trawling condition and vis a versaThere must be a compromise between free running efficiency and tow pull Installed power will be greater than for ideal conditionThe final outcome is that the same engine choice is made for the 75 and 85 foot vessels
Whitelaw & Pearson
CASE STUDY - Capital Cost Comparison
COST CATEGORY 65 BASIS 65 75 85
BASIC HULL AND DECKS $292,875 $343,750 $348,219 $439,313
TOPSIDES & OUTFITTING $542,763 $687,500 $687,500 $687,500
ELECTRONICS $80,000 $80,000 $80,000 $80,000
PROPULSION MACHINERY $135,000 $181,000 $135,000 $135,000
PROP/ STEERING $57,500 $57,500 $65,201 $70,196
HYDRAULICS/ FISHING GEAR $186,300 $186,300 $186,300 $186,300
REFRIGERATION $30,000 $30,000 $30,000 $30,000
TOTAL CAPITAL COST (MILLIONS) $1.324 $1.566 $1.532 $1.628
Whitelaw & Pearson
Life Cycle Costing Model
Capital InvestmentFuelInsuranceVessel Maintenance
Whitelaw & Pearson
CASE STUDY - Operating Profile
Fishing between April and November
SHRIMP:12 TRIPS - 200 NM
OFFSHORE– To/from grounds @ 10
knots– 48 Hours Trawling @ 2.5
knots
Whitelaw & Pearson
Life Cycle Costing Model
BASESCAPITAL INVESTMENT – 15 YEARS @ 8%ANNUAL FUEL – TRIP PROFILE and SPECIFIC FUEL CONSUMPTIONINSURANCE - $31.00 per $1000 VESSEL COSTMAINTENANCE – HULL SURFACE AREA
VESSELCAPITAL
INVESTMENTANNUAL FUEL
ANNUAL INSURANCE
ANNUAL MAINTENANCE
TOTAL
65 x 24 $154,680 $22,700 $41,050 $42,500 $260,930
65 x 30A $182,960 $29,600 $48,550 $45,000 $306,110
75 x 27.7 $179,008 $21,800 $47,500 $45,000 $293,308
85 x 31.4 $190,235 $20,800 $50,500 $55,000 $316,535
Whitelaw & Pearson
Conclusions
Capital Cost Differences TrivialCapital Cost increases are Offset by Fuel SavingsTotal Yearly Costs Differences are only +/- 3%Opportunity to Improve Design Fundamentals
Whitelaw & Pearson
Conclusions - Intuitive
Longer, more slender vessels require less power than short fat ones at the same design speed – or there is an opportunity to take advantage of greater speeds with similar powerImproved free running performance in a seaway in the longer vessels due to improved pitch performance Improved towing performance in a seaway in the longer vessels due to improved pitch performance Better directional stability and therefore safety in a seawayImproved operability or “working” time for the longer vessels due to improved motionsOpportunity for improved layout on deck and below