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Subelement D
Other Equipment
Section 20
Power Sources
For a small passenger vessel inspection, reserve power batteries must be tested:
  • At intervals not exceeding every 3 months.
  • At intervals not exceeding every 6 months
  • Before any new voyage
  • Correct Answer
    At intervals not exceeding 12 months, or during the inspection.

For a small passenger vessel inspection, reserve power batteries must be tested:

At intervals not exceeding 12 months, or during the inspection.

Practical testing advice on MySeaTime site, article GMDSS Batteries: Tests and checks mariners must know

Inspection guide from National Marine Electronics Association How to Conduct a Great Lakes Small Passenger Vessel Inspection

Comprehensive small vessel requirements from US Coast Guard on Small Passenger Vessel Guide

For battery regulations, Code of Federal Regulations, Title 46 Chapter I Subchapter T Part 183:
§ 183.350 Batteries - general.
§ 183.352 Battery categories.
§ 183.354 Battery installations.

Title 47 Chapter I Subchapter D Part 80 Subpart S
§ 80.915 Main power supply.
§ 80.917 Reserve power supply.
§ 80.919 Required capacity.
§ 80.963 Main power supply.
§ 80.965 Reserve power supply.

Title 47 Chapter I Subchapter D Part 80 Subpart I
§ 47 CFR 80.409 Station logs.

47 CFR 80.409(e)(7) An entry at least once every thirty days that the batteries or other reserve power sources have been checked and are functioning properly.

Last edited by markadlerdallas. Register to edit

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What are the characteristics of the Reserve Source of Energy under GMDSS?
  • Supplies independent HF and MF installations at the same time.
  • Cannot be independent of the propelling power of the ship.
  • Correct Answer
    Must be independent of the ship’s electrical system when the RSE is needed to supply power to the GMDSS equipment.
  • Must be incorporated into the ship’s electrical system.

What are the characteristics of the Reserve Source of Energy under GMDSS?

Must be independent of the ship’s electrical system when the RSE is needed to supply power to the GMDSS equipment.

NOTE:> There are two CFR paragraphs in this area, please scan over the below requirements to get an overview of what is required. It is a good investment in time.

Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart
R - Technical Equipment Requirements for Cargo Vessels Not Subject to Subpart W

§80.860 Reserve power supply.

47 CFR 80.860(a) When the main power supply is not on the same deck as the main wheelhouse or at least one deck above the vessel's main deck, a reserve power supply must be provided and must be so situated.

The location of the reserve power supply must be located as near to the required transmitter and receivers as practicable and meet all applicable rules and regulations of the United States Coast Guard.

47 CFR 80.860(b) The reserve power supply must be independent of the propelling power of the ship and of any other electrical system, and must simultaneously energize the radiotelephone transmitter at its required antenna power, the required receivers, the emergency light and the automatic radiotelephone alarm signal generator. The reserve power supply must be available at all times.


Additional requirements in this paragraph:

47 CFR 80.860(c) The reserve power supply may be used to energize the bridge-to-bridge radiotelephone and the VHF radiotelephone installation required by § 80.871.

47 CFR 80.860(d) All circuits connected to the reserve power supply must be protected from overloads.

47 CFR 80.860(e) Means must be provided for charging any batteries used as a reserve power supply. A continuous indication of the rate and polarity of the charging current during charging of the batteries must be provided.

47 CFR 80.860(f) The cooling system of each internal combustion engine used as a part of the reserve power supply must be adequately treated to prevent freezing or overheating consistent with the season and route to be traveled by the particular vessel involved.

47 CFR 80.860(g) The reserve power supply must be available within 1 minute.


Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart W - Global Maritime Distress and Safety System (GMDSS)

§ 80.1099 Ship sources of energy.

47 CFR 80.1099(a) There must be available at all times, while the ship is at sea, a supply of electrical energy sufficient to operate the radio installations and to charge any batteries used as part of a reserve source of energy for the radio installations.

47 CFR 80.1099(b) A reserve source of energy to supply radio installations must be provided on every ship for the purpose of conducting distress and safety radiocommunications, in the event of failure of the ship's main and emergency sources of electrical power.

Last edited by markadlerdallas. Register to edit

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Which of the following terms is defined as a back-up power source that provides power to radio installations for the purpose of conducting Distress and Safety communications when the vessel’s main and emergency generators cannot?
  • Emergency Diesel Generator.
  • Correct Answer
    Reserve Source of Energy.
  • Reserve Source of Diesel Power.
  • Emergency Back-up Generator.

Which of the following terms is defined as a back-up power source that provides power to radio installations for the purpose of conducting Distress and Safety communications when the vessel’s main and emergency generators cannot?

Reserve Source of Energy.

NOTE:> There are two CFR paragraphs in this area, please scan over the below requirements to get an overview of what is required. It is a good investment in time.

Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart
R - Technical Equipment Requirements for Cargo Vessels Not Subject to Subpart W

§80.860 Reserve power supply.

47 CFR 80.860(a) When the main power supply is not on the same deck as the main wheelhouse or at least one deck above the vessel's main deck, a reserve power supply must be provided and must be so situated.

The location of the reserve power supply must be located as near to the required transmitter and receivers as practicable and meet all applicable rules and regulations of the United States Coast Guard.

47 CFR 80.860(b) The reserve power supply must be independent of the propelling power of the ship and of any other electrical system, and must simultaneously energize the radiotelephone transmitter at its required antenna power, the required receivers, the emergency light and the automatic radiotelephone alarm signal generator. The reserve power supply must be available at all times.


Additional requirements in this paragraph:

47 CFR 80.860(c) The reserve power supply may be used to energize the bridge-to-bridge radiotelephone and the VHF radiotelephone installation required by § 80.871.

47 CFR 80.860(d) All circuits connected to the reserve power supply must be protected from overloads.

47 CFR 80.860(e) Means must be provided for charging any batteries used as a reserve power supply. A continuous indication of the rate and polarity of the charging current during charging of the batteries must be provided.

47 CFR 80.860(f) The cooling system of each internal combustion engine used as a part of the reserve power supply must be adequately treated to prevent freezing or overheating consistent with the season and route to be traveled by the particular vessel involved.

47 CFR 80.860(g) The reserve power supply must be available within 1 minute.


Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart W - Global Maritime Distress and Safety System (GMDSS)

§ 80.1099 Ship sources of energy.

47 CFR 80.1099(a) There must be available at all times, while the ship is at sea, a supply of electrical energy sufficient to operate the radio installations and to charge any batteries used as part of a reserve source of energy for the radio installations.

47 CFR 80.1099(b) A reserve source of energy to supply radio installations must be provided on every ship for the purpose of conducting distress and safety radiocommunications, in the event of failure of the ship's main and emergency sources of electrical power.

Last edited by markadlerdallas. Register to edit

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In the event of failure of the main and emergency sources of electrical power, what is the term for the source required to supply the GMDSS console with power for conducting distress and other radio communications?
  • Emergency power.
  • Ship’s emergency diesel generator.
  • Correct Answer
    Reserve source of energy.
  • Ship’s standby generator

In the event of failure of the main and emergency sources of electrical power, what is the term for the source required to supply the GMDSS console with power for conducting distress and other radio communications?

Reserve source of energy.

NOTE:> There are two CFR paragraphs in this area, please scan over the below requirements to get an overview of what is required. It is a good investment in time.

Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart
R - Technical Equipment Requirements for Cargo Vessels Not Subject to Subpart W

§80.860 Reserve power supply.

47 CFR 80.860(a) When the main power supply is not on the same deck as the main wheelhouse or at least one deck above the vessel's main deck, a reserve power supply must be provided and must be so situated.

The location of the reserve power supply must be located as near to the required transmitter and receivers as practicable and meet all applicable rules and regulations of the United States Coast Guard.

47 CFR 80.860(b) The reserve power supply must be independent of the propelling power of the ship and of any other electrical system, and must simultaneously energize the radiotelephone transmitter at its required antenna power, the required receivers, the emergency light and the automatic radiotelephone alarm signal generator. The reserve power supply must be available at all times.


Additional requirements in this paragraph:

47 CFR 80.860(c) The reserve power supply may be used to energize the bridge-to-bridge radiotelephone and the VHF radiotelephone installation required by § 80.871.

47 CFR 80.860(d) All circuits connected to the reserve power supply must be protected from overloads.

47 CFR 80.860(e) Means must be provided for charging any batteries used as a reserve power supply. A continuous indication of the rate and polarity of the charging current during charging of the batteries must be provided.

47 CFR 80.860(f) The cooling system of each internal combustion engine used as a part of the reserve power supply must be adequately treated to prevent freezing or overheating consistent with the season and route to be traveled by the particular vessel involved.

47 CFR 80.860(g) The reserve power supply must be available within 1 minute.


Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart W - Global Maritime Distress and Safety System (GMDSS)

§ 80.1099 Ship sources of energy.

47 CFR 80.1099(a) There must be available at all times, while the ship is at sea, a supply of electrical energy sufficient to operate the radio installations and to charge any batteries used as part of a reserve source of energy for the radio installations.

47 CFR 80.1099(b) A reserve source of energy to supply radio installations must be provided on every ship for the purpose of conducting distress and safety radiocommunications, in the event of failure of the ship's main and emergency sources of electrical power.

Last edited by markadlerdallas. Register to edit

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What is the requirement for emergency and reserve power in GMDSS radio installations?
  • An emergency power source for radio communications is not required if a vessel has proper reserve power (batteries).
  • A reserve power source is not required for radio communications.
  • Only one of the above is required if a vessel is equipped with a second 406 EPIRB as a backup means of sending a distress alert.
  • Correct Answer
    All newly constructed ships under GMDSS must have both emergency and reserve power sources for radio communications.

{NOTE: The Practice test has a flaw due to the randomization of the order of the multiple-choice answer candidates. For example, I saw candidate answer A as " Only one of the above is required if a vessel is equipped with a second 406 EPIRB as a backup means of sending a distress alert." where there is nothing above A. Presumably other misalignments can occur.}

What is the requirement for emergency and reserve power in GMDSS radio installations?

All newly constructed ships under GMDSS must have both emergency and reserve power sources for radio communications.

NOTE:> There are two CFR paragraphs in this area, please scan over the below requirements to get an overview of what is required. It is a good investment in time.

Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart
R - Technical Equipment Requirements for Cargo Vessels Not Subject to Subpart W

§80.860 Reserve power supply.

47 CFR 80.860(a) When the main power supply is not on the same deck as the main wheelhouse or at least one deck above the vessel's main deck, a reserve power supply must be provided and must be so situated.

The location of the reserve power supply must be located as near to the required transmitter and receivers as practicable and meet all applicable rules and regulations of the United States Coast Guard.

47 CFR 80.860(b) The reserve power supply must be independent of the propelling power of the ship and of any other electrical system, and must simultaneously energize the radiotelephone transmitter at its required antenna power, the required receivers, the emergency light and the automatic radiotelephone alarm signal generator. The reserve power supply must be available at all times.


Additional requirements in this paragraph:

47 CFR 80.860(c) The reserve power supply may be used to energize the bridge-to-bridge radiotelephone and the VHF radiotelephone installation required by § 80.871.

47 CFR 80.860(d) All circuits connected to the reserve power supply must be protected from overloads.

47 CFR 80.860(e) Means must be provided for charging any batteries used as a reserve power supply. A continuous indication of the rate and polarity of the charging current during charging of the batteries must be provided.

47 CFR 80.860(f) The cooling system of each internal combustion engine used as a part of the reserve power supply must be adequately treated to prevent freezing or overheating consistent with the season and route to be traveled by the particular vessel involved.

47 CFR 80.860(g) The reserve power supply must be available within 1 minute.


Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart W - Global Maritime Distress and Safety System (GMDSS)

§ 80.1099 Ship sources of energy.

47 CFR 80.1099(a) There must be available at all times, while the ship is at sea, a supply of electrical energy sufficient to operate the radio installations and to charge any batteries used as part of a reserve source of energy for the radio installations.

47 CFR 80.1099(b) A reserve source of energy to supply radio installations must be provided on every ship for the purpose of conducting distress and safety radiocommunications, in the event of failure of the ship's main and emergency sources of electrical power.

Last edited by sdubuis. Register to edit

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What is the meaning of “Reserve Source of Energy”?
  • Correct Answer
    The supply of electrical energy sufficient to operate the radio installations for the purpose of conducting Distress and Safety communications in the event of failure of the ship’s main and emergency sources of electrical power.
  • High caloric value items for lifeboat, per SOLAS regulations.
  • Diesel fuel stored for the purpose of operating the powered survival craft for a period equal to or exceeding the U.S.C.G. and SOLAS requirements.
  • None of these.

What is the meaning of “Reserve Source of Energy”?

The supply of electrical energy sufficient to operate the radio installations for the purpose of conducting Distress and Safety communications in the event of failure of the ship’s main and emergency sources of electrical power.

NOTE:> There are two CFR paragraphs in this area, please scan over the below requirements to get an overview of what is required. It is a good investment in time.

Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart
R - Technical Equipment Requirements for Cargo Vessels Not Subject to Subpart W

§80.860 Reserve power supply.

47 CFR 80.860(a) When the main power supply is not on the same deck as the main wheelhouse or at least one deck above the vessel's main deck, a reserve power supply must be provided and must be so situated.

The location of the reserve power supply must be located as near to the required transmitter and receivers as practicable and meet all applicable rules and regulations of the United States Coast Guard.

47 CFR 80.860(b) The reserve power supply must be independent of the propelling power of the ship and of any other electrical system, and must simultaneously energize the radiotelephone transmitter at its required antenna power, the required receivers, the emergency light and the automatic radiotelephone alarm signal generator. The reserve power supply must be available at all times.


Additional requirements in this paragraph:

47 CFR 80.860(c) The reserve power supply may be used to energize the bridge-to-bridge radiotelephone and the VHF radiotelephone installation required by § 80.871.

47 CFR 80.860(d) All circuits connected to the reserve power supply must be protected from overloads.

47 CFR 80.860(e) Means must be provided for charging any batteries used as a reserve power supply. A continuous indication of the rate and polarity of the charging current during charging of the batteries must be provided.

47 CFR 80.860(f) The cooling system of each internal combustion engine used as a part of the reserve power supply must be adequately treated to prevent freezing or overheating consistent with the season and route to be traveled by the particular vessel involved.

47 CFR 80.860(g) The reserve power supply must be available within 1 minute.


Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart W - Global Maritime Distress and Safety System (GMDSS)

§ 80.1099 Ship sources of energy.

47 CFR 80.1099(a) There must be available at all times, while the ship is at sea, a supply of electrical energy sufficient to operate the radio installations and to charge any batteries used as part of a reserve source of energy for the radio installations.

47 CFR 80.1099(b) A reserve source of energy to supply radio installations must be provided on every ship for the purpose of conducting distress and safety radiocommunications, in the event of failure of the ship's main and emergency sources of electrical power.

Last edited by markadlerdallas. Register to edit

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