fuel problem

[fireftr18]

In general, 9 to 10 knots will give you the most efficient diesel fuel consumption. I don't know the physics of it, but slower speeds tend to use more fuel. With electric, the slower, the longer the batteries last. When you use electric, you need to charge the batteries. The diesels will run full to until the batteries are charged. That uses an incredible amount of fuel. Best to run on surface as much as you can at a moderate speed. Only submerge to avoid aircraft and destroyers, then run at slow speed.

[hcs53]

Thanks for your reply

I must go to the Japan-luzon Straits with my Porpoise.
I always use the speed of 9kn.
I did not know about"The diesels will run full to until the batteries are charged. That uses an incredible amount of fuel".

I am going to read the instructions in ISP.

Henny

[TorpX]

I must go to the Japan-luzon Straits with my Porpoise.

Ah, that explains it.

Cruising at ~ 9.0 kn. is the most fuel efficient. fireftr18 is right that battery charging will use up more fuel, but I wouldn't freak out about it.

With ISP, you will be able to get better battery performance than you would otherwise. I was able to patrol all day at 3 kn. submerged, surface, charge batteries, and move 30 nm overnight using about 1% fuel per day. That in a S-boat. I don't remember exactly how much fuel is used by charging, but it is approximately proportional to the amount of depletion. So, it you run submerged at a low speed, say 3 kn., you should not use more than about 30 % of your battery. This can be recharged without an enormous quantity of fuel.

[hcs53]

I started again the journey from Midway to HaHa Lima, 4786km my fuel level is 72/100.
Very good weather,no diving,only surfaced at 9kn
What do you think?

henny

[TorpX]

That looks about right.

Later on, when you have forward bases, you'll appreciate the advantage.