Canadian Polar Icebreaker John G. Diefenbaker

Some information from Canadian ship design agency VARD, on the planned Canadian polar icebreaker John G. Diefenbaker. The project is long delayed and construction has not yet begun.

There is much more detail in the VARD brochure and Wikipedia entry linked above, but a few significant data points.

• Displacement, full load: 23,500 tons
• Length overall: 150.1 m 492’-6”
• Length waterline: 137.6 m 451’-5”
• Breadth moulded 28.0 m 91’-10”
• Design draft: 10.5 m 34’-6”
• Generators: 39,600 kW 53,100 hp
• Propulsion: two 11 MW (14,751 hp) wing shafts and a 12 MW (16,092 hp) azimuth thruster. total 34 MW (45,595 hp),
• Speed: 18 knots ice free, 3.0 kn, 2.5m ice 
• Range:  26,000 NM @ 12 kn ice free 
• 1,800 NM @ 3.0 kn 2.2 m of ice
• 60 core crew + 40 program personnel
• Endurance  270 days

For comparison these are figures for the planned Polar Security Cutter. Projected delivery dates, 2024, 2025, 2027.

• Displacement, Full Load: 22,900 tons
• Length: 460 ft (140 meters)
• Beam: 88 ft (26.8 meters)
• HP: 45,200
• Accommodations: 186
• Endurance: 90 days

In many ways the designs are remarkably close. Looks like the Canadian breaker will be slightly larger than the PSC, but will have a much smaller crew.

Presumably there will be no provision for armament since the Canadian Coast Guard does not arm its vessels.

The Diefenbaker’s very long endurance is a bit of a surprise, in view of Canada’s lack of a requirement to go to Antarctica, a feature that has driven the design of the PSC.

Propulsion power is almost identical, a bit over 45,000 HP, and both designs include three propellers, but the way it is done is different. While the PSC has a conventional shaft on the centerline and rotatable drive units to port and starboard, the Canadian design has a single rotating drive unit on the centerline and conventional shaft driven props port and starboard. This may provide the PSC with a redundancy advantage in that it might allow steerage even if one unit is damaged. On the other hand the single Canadian unit may be less likely to be damaged because of its position.