1987 Commercial LCM 8

NEW TO MARKET, LCU-8, BUILT FOR US NAVY, EXCELLENT CONDITION! EVERYTHING WORKING 

LCM-8 "Mike Boat" Specifications Often called the "Mike Boat," the  LCM-8 is a rugged, steel-hulled vessel designed for transporting heavy equipment and troops from ship to shore.  

Length Overall: According to Wikipedia and Ocean Support Vessels, the craft measures approximately 73 feet 7 inches to 74 feet.

Beam: 21 feet.

Displacement: Approximately 105 to 111 long tons when fully loaded.

Propulsion: Typically powered by two Detroit 12V-71 diesel engines providing 680 hp sustained to twin shafts.

Capacity: It can carry one M48 or M60 tank, or up to 200 combat troops, 60 DWT.

Performance: A maximum speed of 12 knots light or 9 knots when fully loaded, with a range of 190 nautical miles.

LCM-8 "Mike Boat" (74-Foot Craft)The LCM-8 is designed for short-range ship-to-shore shuttle operations rather than independent long-distance travel.

Fuel Capacity:

Standard Military Spec: Approximately 864 gallons.

Commercial/Private Builds: Varies by modification; for example, a 1972 Gunderson Marine build is listed with a 640-gallon capacity across two tanks. Other variants have been recorded with up to 900 gallons.

Range:

Full Load: 190 nautical miles at a speed of 9 knots.

Light (Unloaded): Approximately 332 nautical miles at 11 knots.

Extended Range: Some modified or civilian versions claim a range of about 400 miles with a 60-ton load.

Fuel consumption for the Detroit 12V-71 engine varies significantly based on engine "tune" (naturally aspirated vs. turbocharged), RPM, and load. In a 74-foot craft like an LCM-8, which typically uses twin engines, you must double these figures for a total vessel burn rate. 

Hourly Fuel Consumption (Per Engine)

Idle / Low Speed (1,000 RPM): ~5 to 9 gallons per hour (GPH).

Cruising (1,200–1,500 RPM): ~12 to 24 GPH.

High Cruise (1,800–1,900 RPM): ~40 to 54 GPH.

Wide Open Throttle (2,100–2,300 RPM): ~65 to 80 GPH. 

Trip Cost Calculation FactorsTo estimate costs for a specific trip, use the following variables:

Standard Efficiency: A common "rule of thumb" for these two-stroke diesels is 1 gallon per hour for every 20 horsepower produced.

Twin Engine Total: For an LCM-8 at a steady 10-knot cruise (approx. 1,200 RPM), expect a combined burn of roughly 25 GPH.

Engine Type: Turbocharged (12V-71T/TI) models are generally more efficient per horsepower than naturally aspirated (12V-71N) models, but they produce more power and can burn more total fuel at high RPMs.

"Wet Stacking" Risk: Running these engines below 1,300 RPM for extended periods is often discouraged as it can lead to incomplete combustion and carbon buildup. 

Estimate Formula

For example, a 50-nautical-mile trip at 10 knots (5 hours) burning 25 GPH total would consume 125 gallons of diesel.

74' x 22' x 4

Hydraulic bow ramp

Built by Bender Shipbuilding, Alabama

Gross tonnage: 95 ton

Net tonnage: 76 tons

Hull depth: 9'

Head room: Cabin - 7', Engine room - 6'.

Shell plate thickness: 1/4"

Bulkhead thickness: 1/4"

(2) 12V-71 Detroit Diesel engines

Steering: Hydraulic

Propellers: 34" x 24"

Fuel capacity: 900 gal

Fuel consumption: 12 GPH

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