I constantly get asked "Why not just replace the existing diesel engine and transmission? Here are the trade-offs:

DIESEL-ELECTRIC

  1. Two existing generators AC 240v
    • Reliable
    • Easy to maintain
  2. Install two AC electric motors, one direct to shaft, the other belt-driven
    1. Very reliable
    2. Cheap to buy
    3. Easy to install
    4. Cheap to install
    5. Inherently a dual-redundant system
    6. Can only propel at 3.5 to 4kt based on experimentation
    7. Very easy to replace failed electric motors

Single points of failure:

  • Propshaft
  • Stuffing box
  • Propeller
DIESEL ENGINE
  1. Install replacement diesel engine and transmission
    1. Fairly reliable
    2. Fairly expensive to install
    3. More maintenance required than electric motors
    4. Faster - a 100HP naturally-aspirated diesel may propel at 5kt
    5. Very difficult to replace failed engine or transmission
    6. Requires raw water cooling intake, strainer connection
    7. Requires water-lift engine exhaust connection

More single points of failure:

  • Transmission
  • Engine
  • Propshaft
  • Stuffing box
  • Propeller
All the above assumes delivery of clean fuel (I have a very effective fuel polishing system and more RACORS/filters than will ever be needed...)

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Discussion Forum

TRADE-OFF ANALYSIS

Started by Captain Ray Thackeray, IRG Sep 5. 0 Replies

TYPES OF MOTOR

Started by Captain Ray Thackeray, IRG. Last reply by Captain Ray Thackeray, IRG Sep 3. 2 Replies

BATTERY DISCUSSION

Started by Captain Ray Thackeray, IRG. Last reply by Captain Ray Thackeray, IRG Sep 1. 1 Reply

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