MK 20 UBA Flashcards
What are the depth limits of the MK 20?
Surface Supplied - 60’
Scuba Mode - 190’
What are the two MK 20 configurations and their differences?
MOD 0 - Positive Pressure
MOD 1 - Non- Positive Pressure (mainly for scuba mode to conserve air)
What are the four major assemblies for the MK 20 MOD 0 and MOD 1?
- Full Face Mask (FFM) Assembly
- Umbilical-to-Mask Hose Assembly
- Communications Assembly
- Harness Assembly
What are the two different materials and three colors the Mask Body comes in?
Colors: Black, Gray and Yellow
Materials: Silicone and Natural Rubber
What may be used to aid in getting a proper seal?
Tygon Tubing
Which MK 20 configuration is required when diving in category 3 contaminated water?
MOD 0
For the MOD 0, what is the approximate positive pressure in the FFM that helps prevent water from entering the mask?
.03 psi
Which MK 20 configuration has a built in lever assembly on the second stage regulator?
MOD 0
What is the overbottom for the MK 20 that is surface supplied?
90 psig
What is the overbottom for the MK 20 that is in SCUBA mode?
Set to manufacture’s recommended pressure, but no lower than 135 psig
The air supply system must be able to provide a sustained flow of what to the divers?
1.4 acfm
Air consumption varies between what range? (with occasional faceplate and make clearing)
0.75 - 1.5 acfm
What breathing rate is considered free flow mode?
8 acfm
How many non-return valves does the MK 20 have?
Two
The built in relief in the MOD 0 and MOD 1 second stage regulator will lift and reset at what pressure?
Lift: 210 +/- 36 psig
Reset: 10 psig below set pressure
What is the length, inside diameter and hose rating of the Umbilical-to-Mask Hose Assembly?
Length: 30 inches long
Inside Diameter: 5/16
Hose Rating: 250 psi
Mission Maintenance is required prior to a mission only if?
- Equipment has never been used
- Equipment has been idle for more than 18 months
- Condition of equipment is suspect
What is an extended dive mission?
A dive mission that exceeds 30 days without any one break in service of seven days or more.
When is a mission is due when?
- If a break in service of seven days or more is anticipated
- 30 day milestone is reached during extended dive mission
SCUBA mode may be used if?
An ANU approved single hose first stage regulator with and an octopus, to the approved depth of the regulator as indicated in the ANU
What current speed requires extra weight?
1.5 knots
What are the MMP requirements for MK 20?
(Depth / .445) + 90 = MMP
*round up to the next whole number
What breathing mode is considered heavy work?
6 acfm
