Fuel Tank Setup?

[Quixotic]

Hoping to get some opinions from some of the experts here.

I am a little skeptical of my diesel fuel tank setup. My auxiliary diesel is supplied by a gravity fed tank which is mounted under the starboard cockpit locker slightly above my diesel engine. There is a shutoff valve at the bottom of the tank with a short length of hose that connects to a "T". From the other side of the "T" the hose goes uphill to my primary filter then back down to the engine mounted lift pump, secondary filter and so on. From the the top of the "T" there is a clear hose that extends just above the height of the tank into the starboard cockpit locker and is fitted with a brass barbed nipple. The clear tube serves as a sight gauge and also as a vent I assume. The fuel return line comes from the aft end of the fuel injectors and connects to a a copper pipe connected to the top of the fuel tank. I have several questions regarding the setup.

First, is this gravity fed system a good idea or should change it?

Second, I am very skeptical of the sight gauge/vent line or whatever it is. It can and does leak fuel when I am on a starboard tack. I like the convenience of the sight gauge but will gladly toss it if it is a bad idea to have. Also could it be modified and how?

What is the "standard way" to setup this system?

[DeepFrz]

You have what is called a "day tank". Day tanks are supplied with filtered fuel from the fuel tank and gravity feed the engine, thereby assuring (?) clean fuel to the engine. In some ways this simplifies the fuel system, in some ways makes it more complicated.

A sight tube can be great but it needs a valve so it is shutoff when running. In your case a valve at the top of the sight tube would be a good idea. You might want to mount it so you can calibrate the fuel level in the day tank.

[Quixotic]

I am familiar with the day tank setup I used one for the first time this past summer while crewing on a delivery and this is definitely my main tank (it's the only one on the boat).