Adding Auxiliary Tank

[Lite Tackle]

After going back and forth on the future of fuel holding and boat balance for the 226, a decision has been reached. Gave serious thought to replacing the main and only tank currently rigged. The idea was have a new 92 gallon tank built and move the location forward to balance out the added weight of the new F250 and the T9.9 kicker. Placement of the fill, vent and sender repositioned to remain under the deck inspection plates. This was drawn out and quotes received from a number of fabricators from local to Florida. Prices shipped to my business was from $875 to $2100.

Since the main tank has yet to reveal any leaks and after inspection of tank it appears sound (knowing this “appearance” can be very deceiving), I began to rethink things. Knowing that Grady was kind enough to rig for an aux tank even if not installed and the hoses looked like new, I thought maybe add the second tank. Received drawing from GW. Back to sourcing fabricators. Found a local commercial aluminum boat builder who was looking for small projects between builds and I gave him the job. He turned out to be a very poor communicator and after not hearing from him for a couple weeks, went back to my original plan of the relocated main tank. Ordered up from a shop in Arizona for a really great price (but 1 month lead-time). Two days later, local guy says your tank is ready, WTF? Ok, contacted shop in Arizona and provided a redesign with original GW 92 gallon tank. No issue with them as they had not started tank.

So, I will have factory spec’ed main and aux tank when done. Found correct switch, McGill 0852-269, SPDT to swap between senders. Side note, GW even has pink/white sender wire rigged for aux tank. At switch panel they routed the main tank sender wire the full length of the switch panel and back to gauge to allow for cutting and terminating at switch (pink wire). Well thought out. New Perko fuel fill, Moeller Fuel Tank Three-Way Valve with fittings, various SS hose clamps and 25’ of 3/8” fuel line.

Picked up new aux tank last night. Work appears good. Plan on using 1/2” thick, 2” strips of neoprene glued to tank for mounting. Need to lift coffin lid later and dry fit to get a better idea for final fitting. Started rigging today. Fill/vent installed and hoses fastened. Kind of a pita. Tight quarters and no leverage. Switch wired and valve installed.

Few pics of progress and will update as progress continues:

 

[leeccoll]

"Kind of a pita"??

For those who have redone the hoses, I would say for me was a harrowing experience lol.

Looks good, and my 228G also has aux hoses from the factory installed incase I want to add an auxiliary tank. Nice touch by Grady White.

You are extremely fortunate you don't have to change out the hoses. That was the most challenging part for me.

Keep us posted and good luck with the install!

 

[Greyduk]

What is the capacity of the aux tank?

 

[Lite Tackle]

 

[Lite Tackle]

Went with .125 aluminum, so 55 3/4 gallons or so (lol).

I have hit a stump. Really was expecting the tank to fill out the coffin a bit better. That’s what I get for relying on the GW drawing. Gonna have to rethink the support and securing of the tank.

 

[Greyduk]

LT, do you think there might have been extra space in the cavity for a water tank and that is why there is so much extra room? Maybe Ky Grady can shed some light on this since he recently replaced his aux tank. I would be interested to hear since I only have a main tank in my boat.

 

[Lite Tackle]

Ya, there’s a shelf between the two fuel tank locations for the water tank. My issue is the angles of the belly tank are nowhere close to matching the hull. The flat is closer to 16” across and the diagonals are about 3” across. Not like drawing. Was planning on adding strips of neoprene to diagonal section (port to starboard). Now it looks like the strips will be on the bottom of tank bow to stern like Grady’s install. No problem, just opportunity.

 

[Greyduk]

Now that you mention it, I think I see the shelf in the picture with the tank in place. Did you have to cut the sides much to get the tank to go in?

 

[Lite Tackle]

No cutting at all. Had it made 3/4” narrower than GW drawing.

 

[Greyduk]

That is exactly what I was thinking. Since I don't have an aux tank to take out and the space is open and if the hoses are there in mine, it would be much less of a problem than otherwise. Are you going to shim on each side of the tank?

 

[Lite Tackle]

Yes, just got to come up with the design. Got right about 1 3/4” of space on each side. Thinking I will fiberglass in 1 1/2”x2” wood shims (3 each side and cuddly end) at top of tank with 1/4” neoprene glued to it spaced evenly. Come off the top of wood shim with 1” starboard to secure tank down. Trying to avoid going out in morning. I have all above material on hand. For stern end, I’ll have to build a new bulkhead off the freshwater tank shelf. Think there will be close to 3 or 4” from shelf to tank. Done thinking about it tonight. Ready for Sharks hockey.

 

[Ky Grady]

Shelf behind auxiliary tank.

 

[Lite Tackle]

Hey Ky, where do the sender wires enter the aux tank box?

 

[Lite Tackle]

Your tank all the way forward and just the 2x4 securing it to the rear?

 

[Ky Grady]

Hey Ky, where do the sender wires enter the aux tank box?

Your tank all the way forward and just the 2x4 securing it to the rear?

Wires and fuel line come into the box on port side through two 1 inch holes at the top of the box. The sender wires run up along port side of back box and into the front box. The auxiliary fuel line comes in in the back starboard corner of back box and crosses main tank and into port side corner of front box. Tank is all the way forward against the two strips shown in the picture. The 2x4 is toe nailed with 2 screws on both sides with a strip of rubber between board and tank. I also have 4 wedges holding tank side to side. Think you need to coat your tanks with some kind of Macropoxy coating to protect them. Raw aluminum won't survive long exposed to the elements.

Here's a pic of my finished installation of both tanks.

 

[Ky Grady]

Found a pic of the wedges on the sides.

 

[Lite Tackle]

Thanks Ky, helps a lot.

 

[DennisG01]

Just an FYI...

It "sounds" like you may be overthinking the securement of the tank. It really doesn't take much to properly secure the tank. What KY did is perfect. Besides, you want it a little bit loose - if you try and secure it too tightly, something will break. A little room for movement is good. Believe me, I've seen A LOT of tanks in my life and how they get installed - in many cases, even less than what KY did... and I've seen those tanks 20 to 30 years of boat use... no issues.

In my opinion, the most important thing (since it's not a plastic tank) is to control corrosion, especially with a bare Al tank. This is done by having proper air gaps all around with no place where water can stay in contact with the Al. Al will self protect itself AS LONG as it's exposed to air. Anything you use to secure the tank should really be glued to the tank first (and fair the edges), then secured to the bulkhead/stringer. In that case, the joint to the bulkhead/stringer would be the "loose" part to allow for some movement.

Point is, don't overthink it by trying to strap the tank down to survive armageddon. Gently held in place is all you need.

 

[Greyduk]

KY, What did you use to make the wedges?

 

[Lite Tackle]

Tank will be primered before final install. Ky had the luxury of having the mounting materials provided by GW. I am working from scratch. Corrosion control is my emphasis is well. My fuel cell box was completely dry and clean. I don’t believe a drop of water has ever been in it in 20 years.

The neoprene strips will be secured to bottom of tank with 5200. I don’t have the wedges from GW for the sides. Could I have them made by taps plastic, or buy the material and fab them myself? Probably. But i think I can do as well with materials I have on site.

My original plan was as explained here: https://www.yachtsurvey.com/fueltank.htm and final product to look like this: https://www.thehulltruth.com/attachment.php?attachmentid=917535&d=1504631729