1985 Catalina 48 fuel tanks question

Remember these were Uniflite boats not original CC. I'm looking at an 1989 with the same setup. Did you ever get your answer?

An arrangement like this should gravity feed to the center tank, however there should also be selector switches so you can draw off one side

The switches are on the bridge to the right of the wheel above the throttles. Small square on the far right, mid picture. Same approximate location on lower helm.

From the Catalina FB page....

If it’s like my 1985 480, the two 157 gallon mains and two 100 gallon aft tanks gravity feed to the center 100 gallon tank. Both engines feed from that tank. Because the mains are higher than the aft tanks, they drain first. Each tank should have a shutoff lever. Fuel gets pulled from the center tank, through the manifold and filters, to the engines. The excess fuel to the engines returns to the mains. My generator was modified to feed directly from the starboard aft tank. Hope this helps.

I have a 1987 catalina 480. 2 tanks in engine room 150 gals each, and one tank, 100 gals, under the floor in aft cabin. Two tanks in lazerette have been removed. All 3 are connected and the aft cabin tank is lower than the engine room tanks and drains last.

I believe ‘IDrankWhat’ is correct. I have a 1987 Catalina 480 with 5 tanks, the two mains in the engine room and 2 aft tanks all gravity feed to the mid or day tank and the engines and generator get there fuel from that tank. The engines return their fuel to the engine room tanks and the generator returns to the day tank. This is the original Chris Craft set up.
I know this because my port main tank shut off clogged and because the port engine was still returning to that tank it overflowed thru the vent! Not the best configuration.
And so, I’m having my tanks polished next weekend.

I'm jumping in late on this thread, but based on what I'm reading and how my 1987 Catalina 480 is configured there may be a variety of arrangements as well as previous owner "customization". My 150 gallon engine room tanks are not original but were replaced by the previous owner in 2016 due to leaking. The previous owner also removed the 95 gallon aft cockpit saddle tanks due to leaking and did not replace them. This caused the boat to float and operate "bow heavy" - The aft tanks are essential in this boat and I had new tanks fabricated after my first year of ownership. I keep them full and only draw from them after the engine room tanks and the aft center belly tank have been drawn down. As far as fuel feeding goes... I have a complex manual valve system on the aft bulkhead of the engine room which allows any tank to feed any engine and also the ability to cross-flow between then engines and tanks for even consumption. While a pain to have to manage while underway, it's straight forward. I did have the feed for the generator moved to only pull from the aft center belly tank for ease of fuel management. FYI - If you run the main engine room tanks completely dry, you will crank the engines forever and a day to draw fuel from the belly tank or aft saddle tanks.

With the two fuel tanks in the lazerette removed, the bow dits a little low. My fresh water holding tanks only hold 120 gallons so i am thinking about replacing the loss of weight in the stern with 2 100 gal fresh water tanks.

If you don't have a need for the fuel capacity, that's a great idea! The 480 craves weight in the stern - I've added all I can and shifted as much from forward as possible and it's just enough.

You mentioned that you had custom tanks made, what dimensions are they?
thanks

Hi there - I think we also communicate on the FB Cat forum.
The tanks I had made aren't really custom, they were made to the original factory spec regarding gauge, pick up locations, size, shape and capacity. I ordered them through Sea Cure Technologies in Washington state.
https://www.unifliteparts.com/about/
If you need dimensions to have custom tanks built I can get them next time I'm on the boat. Otherwise, It's a lot easier to order them from Tim at Sea Cure (and the price was fair as well). The boat NEEDS these tanks and we carry them full of fuel until everything else has burned and then treat them as "reserve" and re-fill them as soon as we are back to port.
You may have realized that your deck drainage isn't quite right? Water flows forward? that issue is mostly fixed my having the aft tanks full. At this time I'm also having forward deck drains installed, since the molds for the deck seem to have a bit of a dip in them right up at the bow.

Thanks for the response, I’ll order them since they are available.
I’ve not noticed the drainage problem

It does not.

Also, while you are doing the aft fuel tanks... It's time to replace the fuel lines that run from the tanks to the fuel distribution manifold (unless they have been cut and you have to anyway). The old lines were installed while the boat was being built, so you will not be able to remove them, only cut off sections that are exposed. The new lines will have to take a different path forward. I suggest routing them up the port side, under the vanity counter, under the aft head counter, then to the engine room.

Thanks, great advice