Trans RINA, Vol 154, Part B2, Intl J Small Craft Tech, Jul-Dec 2014
Effective Thrust
Gear Box 18%
Propulsor 17%
Shaft and bearing losses
1% Vessel
Prime Mover 76%
Alternator 2%
Power Take Off
4%
Heat Losses 52 %
Diesel Fuel 100%
Auxiliary Engine 1
18%
Heat Losses 6.8%
Alternator 5%
Generator Losses
240V
Electrical System
240V
Auxiliary Engine 2 6%
Alternator 2.6 %
Heat Losses 5.4%
Electrical System
Generator Losses
Figure 7: Estimated Chemical Energy Use Break Down of an SESSF Long-line Vessel2
Effective Thrust
Gear Box 14%
Prime Mover
60-64%
Alternator 2%
Hydraulic Pump
4%
Heat Losses 41-44%
Diesel Fuel
100%
Auxiliary Engine
8%
Alternator 2.6%
Heat Losses 5.4%
Auxiliary Engine 28%
Hydraulic Power pack
8%
Heat Losses 16%
Figure 8: Estimated Chemical Energy Use Break Down of Surveyed SESSF Trawler
Closer inspection of vessel operation conditions may allow for the changing of
propeller to better suit
operating conditions. To investigate this option the propeller operating conditions for the vessels surveyed were determined and are summarised in Table 10.
2 Only one auxiliary engine is used at any one time B-64 ©2014: The Royal Institution of Naval Architects 240 V
Electrical System
Generator Losses
Flood Lights
Refrigeration system
Ice Maker
Propulsor 13%
Shaft and bearing losses
1% 24 V
Electrical System
Steering Gear
Anchor Winch
Propulsor losses
10% 3%
Vessel Navigation Systems
Battery Bank
Net
Movement 3%
24 V
Electrical System
Hydraulic Pump
Navigation Systems
Battery Bank
Steering Gear
Anchor Winch
Fishing Gear Figure 9: Recommended Propeller Clearances [11] Flood Lights
Refrigeration system
Ice Maker
In general the propeller diameter should be as large as possible without causing large amounts of vibration. To determine the required propeller clearances to avoid vibration, the recommended guidelines shown in Figure 9 and Table 11 were used.
From these recommendations, the percentage of the propeller diameter recommended clearances for the vessels surveyed were calculated. These are summarised in Table 12.
These clearance dimensions can be used by operators to assess whether they can increase the size of the propeller installed on their vessels.
For vessels that need to tow fishing gear such as a scallop dredge or a trawl net, replacing the existing propeller with accelerating duct and appropriate KAPLAN propeller will decrease the fuel consumption by 8 to 10%. This propeller change has the advantages of:
vessel able to tow a larger trawl net use the same net at a lower engine load
The disadvantage of this is the capital cost which may have a longer return on investment time.
Since most of the vessels operate in the high end of the displacement range when steaming to and from port, reducing the transit speed is an option to reduce fuel consumption.
Net and Warp
Winches
upper end of displacement speed regime the wave resistance
of these 13%
Propulsor Losses
4%
Since the vessels are operating in the vessels increases in magnitude
compared to frictional resistance of the vessel. The biggest advantage of a speed reduction is that it does not require any capital cost. The disadvantage of reducing the steaming speed is the extra time added to each fishing trip. This can have social impacts upon vessel crew (being away from home longer) and also on catch value since the shelf life of fish caught is limited especially when stored in ice or in a fish room. To determine which vessels
could benefit from a speed reduction, the
steaming speeds and durations of the southern rock lobster and SESSF vessels was compiled as shown in Table 13 and Table 14 respectively.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88