Endurance of Basset / Bangor / Bathurst classes (Full Version)

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LargeSlowTarget -> Endurance of Basset / Bangor / Bathurst classes (11/9/2019 11:22:06 AM)

I have long haboured suspicions about the low endurance of the Bangors - 1400 - and Bathurst classes - 1200 - esp. when compared to the smaller and coal-fired Basset class with an endurance of 2000.

A web search brings up pages that indicate endurances between 2600 to 2800 nautical miles for the Bathurst and 4000 to 5900 nautical miles for the Bangors.

Anyone here knows a specific reason why the endurance has been lowered in stock scenarios?

http://jproc.ca/rrp/bangor.html
http://www.navypedia.org/ships/uk/brit_o_esc_bangor_diesel.htm
http://www.navypedia.org/ships/uk/brit_o_esc_bangor_vte.htm
http://www.navypedia.org/ships/uk/brit_o_esc_bangor_turbine.htm

https://www.tracesofwar.com/articles/4707/Australian-corvettes-of-the-Bathurst-class.htm
https://www.navyhistory.org.au/bathurst-class-minesweepers-corvettes/







Dili -> RE: Endurance of Basset / Bangor / Bathurst classes (11/9/2019 3:34:05 PM)

Bangor VTE 150t oil 2400iHP=16.5kt
Bangor Turbine 150t oil 2000shp 16.5 kt
Bangor Diesel 65t oil 2000bhp 16.5kt

Bathurst VTE 124-153t oil 1550-2000ihp 15-16kt

Bathurst have a bigger beam and slight bigger draft so should have less range unless there is something we don't know

Basset had 190t coal so the should not even approach the range.


But you will get many issues with range in database. Ex Japanese destroyers.







LargeSlowTarget -> RE: Endurance of Basset / Bangor / Bathurst classes (11/19/2019 1:31:25 PM)

Ship endurance must be the same can of worms like aircraft range - depends on load, speed, weather and other factors.

In sources, endurance is often indicated for the most economical speed or a specific cruise speed, not the top speed.

For the Bathursts I have found 2640 miles at 10 knots (and a design top speed of 15 knots while in practice they managed only 13 knots "at load draught").

The AE editor manual says "endurance is the number of miles the ship can travel at cruise speed before it expends all of its fuel".

Stock scenario gives them a cruise speed of 12 knots and a top speed of 16 knots and an endurance of 1200 miles.

So 2640 miles at 10 knots IRL but only 1200 miles at 12 knots in the game - can the 2 knots speed difference explain the difference in endurance?

There seems to be a point where fuel consumption is skyrocketing to gain extra speed due to hydrodynamics, but I'm a landlubber and have less than half-knowledge on this topic so maybe a seafaring forumite can provide some insights?




spence -> RE: Endurance of Basset / Bangor / Bathurst classes (11/19/2019 6:41:00 PM)

I served in the USCG at different times on USCGC Duane and USCGC Bibb (both sister ships of USCGC Taney that is in the game). The ships were powered by 2 steam turbines burning Navy Special Fuel Oil (has to be pre-heated to 140 degrees F to flow like a liquid).

Fuel consumption is definitely NOT a linear function of the speed of a ship. It is rather a geometric function. The ordinary speed of the Duane/Bibb was 15kts making 180 rpm on the propellors. That could be done constantly for 2 weeks. The most economical speed of Bibb/Duane was 12 kts which could be managed for around 3 weeks.

When I served on the Duane we could make 22.5 kts at roughly 275 rpm (only did it for 2 hours during a full power trial). When I served on Bibb some years later we were restricted by the Commandant to making no more than 230 turns (due to the age of the boilers) but when we had to meet a Cadet Cruise in San Juan, PR we made that; 18.5 kts (230 turns) for approximately 4 days and we burned around 80% of our fuel capacity IIRC about 160000 gallons of fuel out of 200000 gallons.





LargeSlowTarget -> RE: Endurance of Basset / Bangor / Bathurst classes (11/25/2019 11:26:45 AM)

Thx spence for sharing your experience.




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