Overpowered Trawler???

Just calculated the usage of the Krogen 58'. It doesn't differ much from the 55' but it's interesting as the 58' also gives a range/usage for 6 knots.

Brief specs Krogen 58'
- Length Overall (LOA) 63' 3"
- Length on Deck (LOD) 58' 0"
- Length at Waterline (LWL) 52' 3"
- Beam (Molded) 18' 1"
- Beam (Over Rub Rail) 18' 10"
- Draft (Designed Water Line - DWL) 6' 3" (standard single screw)
- Draft: Twin screw option 5' 3"
- Displacement (DWL with Half Load) 96,830 lb.
- Ballast: (Encapsulated Lead) 7,000 lb.
- Fuel: 1,810 gal. standard single screw.
- Fuel: 1,760 gal. twin screw option.
- Water: 400 gal.

I'm assuming the one given 58' range/usage table is for the 1,810 gallon tankage + single engine & prop version as that's the standard version of the 58'.

I've added for comparison the usage of the twin set up Krogen 55' in dark red, and the topic boat in blue.

Range & Usage
6 kts. 5,690 NM / (1,810 gal. x 0.9) = 3.49 NM/gal. ~ 3.7 NM/gal. ~ is guess from extrapolating below figures.
7 kts. 3,840 NM / (1,810 gal. x 0.9) = 2.36 NM/gal. - 2.54 NM/gal. -
8 kts. 2,590 NM / (1,810 gal. x 0.9) = 1.59 NM/gal. - 1.65 NM/gal. -
9 kts. 1,780 NM / (1,810 gal. x 0.9) = 1.09 NM/gal. - 1.09 NM/gal. - 1 NM/gal. -
10 kts 1,240 NM / (1,810 gal. x 0.9) = 0.76 NM/gal. - 0.71 NM/gal. -
NOTE: Calculated with a 10% reserve. Ranges are approximate.

Interesting is the turning point at 9 kts, below 9 kts the Krogen 55' burns less and above she burns more than the 58'. The 55's max displacement speed there . . ? ?

Cheers,
Angel

 

is guess from extrapolating below figures.

The "Voyaging under Power" book by Beebe has graphs that seem quite accurate at all speeds..

Probably in the library.

FF