Gas Tanks ---- Again

[boatnut]

As we look forward to a major job on the 18 this year including a new tank although no leaks or problems have been detected) and an engine rebuild or replacement, I continue to wonder about this gas tank situation.
1) It is tempting to follow the time-proven rule of "if it ain't broke don't fix it". However your combined knowledge and advice have me now thinking we should change the tank in this 1969 boat. Any new thoughts on this.
2) What really bothers me is I have 1997 22 that seems to have the same tank mounting technique (metal surrounded by foam) that the industry says is wrong and will result in crevice corrosion in metal (stainless, aluminum, or galv steel) over time. Are we all facing this same time bomb in the 22's and newer 18's -- or has Donzi been (finally) smart enough to do something different. If they have solved this problem when (what year) did it enter the production run?
Thanks guys, Happy New Year, Ed

[gcarter]

You know what I think......
But this also backs it up;

http://www.uscgboating.org/recalls/pdfs/BSC79.pdf

Look at page three and four.
It reiterates about good foaming installation, coatings, etc.
I still have several gallons of coal tar epoxy. It's probably the nearest thing to complete isolation there is.

[mattyboy]

however you do it do it now while you have the chance, popping the deck will make the engine rebuild easier to give you a chance to check everything out too

[RickSE]

Donzi started using polly tanks in the 2003 model year. There may be some late 2002MY boats out there with polly tanks but my mid-year 2002 has a steel tank.

[roadtrip se]

built in 9/00 has a poly tank in it.

Hmm, the plot thickens.

Maybe the SE got the metal tank for strength?

[MOP]

The 91 16 of mine had a Poly tank.

Phil

[rustnrot]

Are the poly tanks foamed in?

[Rootsy]

my 97 16 has an aluminum tank...

my 66 18 has no tank :eek!: well actually it has a tank from a 1967 16 sitting in it... that's been groped and prodded and pried on by nearly every donziphile on the east coast. but they took care of her and gave her the best protective coating known to man... a hefty garbage bag :tongue:

[mrfixxall]

When i replace gas tanks in my cust boats i give them the option to have the tank rhino lined on the outside only. It depends on the size usually a 30 gal tank costs $150.00. It also helps the foam stick to the tank better because of the ruff serface. i have also noticed some boat mfr's dont install a piece of pcv under the tank from stringer to stringer to keep the water from getting traped under the tank..good luck
p.s. just make sure you use the two part pour in foam and not the stuff in the cans.

md

[gcarter]

Are the poly tanks foamed in?
Tom, from a support standpoint, I don't think you can beat foam. Particularly in the bilge where the bottom contours are constantly changing.

[Greg Maier]

Rick,
Your SE has a steel tank? You don't hear about many steel tanks.
I've done a lot of tank research and have come to the conclusion that the best tank is a poly rotomolded tank. The only drawback is the lack of baffles. Moeller makes rotomolded tanks in all shapes and sizes including belly tanks that would fit a Donzi.
Moeller Belly Tank (http://www.overtons.com/modperl/overtons/detail/pdetail2.cgi?r=detail_view&item_num=30458&fcat=)

[cigarette30]

This may be a a stupid question ... I know my 04 has the poly, is it better?, and if so, why would that not be the choice of replacement. So many still favor the alum. or steel?

[Greg Maier]

Cigarette 30,

I guess that depends on what you definition of better is. I'm sure that all the different types (Aluminum, Poly, Steel, Fiberglass) hold fuel equally well. But, there are manufacturing, installation and durability issus with all of them except for poly. For instance, aluminum is supposed to be installed in a way that water will never come into contact with it for a prolonged period of time. According to the Coast Guard, aluminum tanks should never be foamed in, even though many peole do. Fiberglass tanks are very difficult to manufacture without pinhole leaks and also expensive. Stainless tanks are prone to cracking and should be avoided. The only drawback that I have read about with poly tanks is that they are not baffled. This is just my opinion, I know there are people on the board who know more about this than I do.

[mattyboy]

I think most choose alumn to replace in older boats as some mfg's still have original tank measurements and still make sight gauges custom made poly tanks are big bucks I couldn't find a poly tank the right size for my 16 I went with a florida marine tanks original equipment replacement

[gcarter]

I think that if ALL of you go back and read the USCG link I posted in #2, it addresses all of the assumptions so many are making here.
To summarise;
Foaming in alum. tks. is good, just do it right.
Many poly tanks fail.
ALL metal tanks can have problems in the area of welds.

Just read the artical, it covers everything.

[cigarette30]

I think that if ALL of you go back and read the USCG link I posted in #2, it addresses all of the assumptions so many are making here.
To summarise;
Foaming in alum. tks. is good, just do it right.
Many poly tanks fail.
ALL metal tanks can have problems in the area of welds.
Just read the artical, it covers everything.

George,

I read the article, and it appeared the summary, provided installation was correct, was that the poly tank would "last the expected lifetime of the boat" Respectively, did I miss the part "many fail"? Great link BTW, maybe I just missed something...... getting old ya know. Thanks

PS, regarding cost, or availabilty, I would think they would be easy to find, just locate where the factory is buying them. It would seem on the surface, this could be the easy and best way for replacement. Again, am I missing something? (are the basic stringer/hull layouts the same in the "classics" since inception, at least where the tanks would go?

[mattyboy]

George,
PS, regarding cost, or availabilty, I would think they would be easy to find, just locate where the factory is buying them. It would seem on the surface, this could be the easy and best way for replacement. Again, am I missing something? (are the basic stringer/hull layouts the same in the "classics" since inception, at least where the tanks would go?

Cig,
no they are not, your classic should be a 40 or so gallon tank, the old ones were setup for a 23-25 gallon tank,the bulkheads are different, the older boats were setup with site gauges in the floor no dash gauge not sure on the newer ones if they still have the site gauge, I had about and 1-2 inches of a gap between the tank and the stringers and bulk head, moving the forward bulk head was out of the question as the front lift ring is attached there and not sure how far back I could have move the rear tank bulk head with out impacting the floor storage locker, plus i didn't want that kind of structural glass work to deal with
again mine being an early classic

i bet ya your lift ring is up by the bow mine is like right in the middle of the deck, donzi used the same the tanks in the 16 and the 18, so when they went to the 40 gallon tank the did it in both models

[gcarter]

George,
I read the article, and it appeared the summary, provided installation was correct, was that the poly tank would "last the expected lifetime of the boat" Respectively, did I miss the part "many fail"? Great link BTW, maybe I just missed something...... getting old ya know.
Take a look at the last paragraph on the left column on page 4. I'm sure they are referring to a minority of tanks.

[boatnut]

Thanks for all the feedback guys, the article is very informative George. After reading the article I believe that it advises that poly (PE) tanks are used in most new boats now and they advise that a PE tank would be a good solution to replace a failed metal tank. They do also say that aluminum could also be a good solution with a lot of "ifs". If it is built correctly, if it is coated correctly, if it is installed correctly, if foamed in the correct foam must be used, if other metals are correctly attached to prevent electrolysis, etc. (Of course the PE tank has some "ifs" also. Being able to get an aluminum tank that is the correct shape and size for our older classics is also a big advantage. Maybe we could get a PE tank mfg to make one to older classic specs if we had enough buyers --lots of us are considering a tank change.
One thing the article doesn't go into in detail is the nature of crevice corosion. Getting a tank (aluminum or stainless) wet with fresh or salt water is ok as long as there is a flow of water or sufficent air (oxygen) available. You can drag aluminum thru salt water continuously and it wouldn't corrode through as the surface would get an oxide coat that would protect it. But if there is dampness or moisture (even condensation) without sufficient oxygen (in air or water) the corrosion happens quickly. I have experienced this on larger boats on both aluminum and stainless parts. So the foam and coatings if they are not perfectly moisture proof cause the problem. Therefore I think it is not good to have metal wrapped in foam in the bilge. However I have had long term issues with "plastics" that seemed to be bullet proof in the short term and then start to deteriorate after many years. I would be willing to try a PE tank if I could find one the correct size. I also think an aluminum tank coated as George described doing in his project would be a good solution (if one is as careful a craftsman as George seems to be). In summary, I think the boat mfgs (especially the good ones) do a lot of good research to ensure they have minimal exposure to warranty costs and liability exposure and if they are switching to PE tanks they must be the better solution. Ed

[MOP]

When you get the tank out measure it, check West Marine you may get lucky RDS supplies their tanks. I found a perfect fit for my 22 about $100 less then getting it direct from RDS. I spoke at length with Donzi, the problem you may run into is the stringers were configued several different ways on the early 18's some tapered toward the front. You may end up with a custom tank.

Phil

[gcarter]

Your points are good Ed.
As I pointed out in my resto thread (Breaks Over), my tank was NOT protected (coated) in any way, just bare aluminum. It had not corroded through, yet.
I think, as you do, if an AL tk is properly prepped (etched, primered, and coated) it will last as long as a PE tk. Additionally, there is much more flexability in an AL tk, RDS will modify the stock design any way you want.
If someone could find a PE tank mfgr who would duplicate a stock 18, Minx 42 gal tk, it would be great.
There's a surplus store in Daytona, Surplus Unlimited, who ALWAYS has 50-80 surplus PE tanks in stock. I can tell you none of them would be suitable for our needs. None of them are more than 20* deadrise, most are less. Additionally, they all seem to be constant section, or nearly so. If you were to use one of their tanks that fit the stringers and bulkheads, it probably wouldn't be more than 30 gal.

[Cuda]

Phil, what year is your 22, and what size tank did it take?

[gcarter]

Phil, what year is your 22, and what size tank did it take?
Joe, keep in mind, Phil added an ADDITIONAL tk.

[hardcrab]

my new aluminum tank for my '66 was built by RDS to my specs.
every dimension was expanded to utilize the max area available.
i dealt with Ray Veal at RDS, he couldn't have been a better resouce. the final product is excellent; complete with baffles, all fittings, sending unit, USCG certification tag and, in primer. i ended up with two spits over 31 gal. capacity.
cost at $400.00 / very satisfied

QUESTION: is an additional tank coating suggested? i noticed in another post that bedliner is being used.

[gcarter]

I added additional zinc phoshpate primer and coated with coal tar epoxy.
I hadn't thought of Rhino Lining, but it might be great if applied properly.

P.S.;
I still have some coal tar epoxy. It's available.

[hardcrab]

I added additional zinc phoshpate primer and coated with coal tar epoxy.
I hadn't thought of Rhino Lining, but it might be great if applied properly.
P.S.;
I still have some coal tar epoxy. It's available.
i don't know what that is, but i'm interested. if you mean it's available as in off the shelf, where would i look? if you mean you have some for sale, feel free to call me; 410 255 1227 ..... johan

[gcarter]

Here's the web site for the product description;
http://www.epoxy.com/216.htm
I had to buy five gallons and used one, then sold one to MOP. The site says it comes in 2 1/2 gallon also, but they haven't done so in quite awhile.
I have th price (what I paid) at my office. I'll look it up tomorrow.
Also take a look at;
http://www.donzi.net/forums/showthread.php?t=36703&page=3
and see how I applied it.

[hardcrab]

excellent post George!
now i want some foul, evil smelling black goop............. enough for a 32 gal. tank (plus a little)

[cigarette30]

Cig,
no they are not, your classic should be a 40 or so gallon tank, the old ones were setup for a 23-25 gallon tank,the bulkheads are different, ...........
so when they went to the 40 gallon tank the did it in both models

Thanks Mattyboy, you sure answered my question ........

[MOP]

Scott is right about poly failure on land equipment we have all seen a lot of that, there must be some differences in boat tanks as they do very well. I have not heard of any failures, possibly they are made of a better, thicker material or just supported better..
The biggest consideration when installing any tank be it poly or metal is secure mounting and ventilation in the case of metal tanks. We can argue the merits of platform "vs" foam, foam gives the best support eliminates flexing and adds structural integrity to the boat. If platform mounted the bottom must be well supported from end to end to eliminate flexing, it must be secured in a manner not to allow any motion what so ever. A tank without proper bottom and side support is surely doomed to early failure! In all cases the compartment must have good ventilation and drainage. I think there is way to much ‘To Do" about foamed aluminum tank failures, if you go back over the tank posts the majority of tanks being or having been changed gave many years good service. Some around 30 years far more years then most will ever own their boats.

To answer Joe's ? "Phil, what year is your 22, and what size tank did it take?" Its an 86 like George said I added a 40 gal tank directly behind the original. The original tank is fine, I just wanted to move the CG aft which I believe worked well as I use far less trim at speed.

Phil

[DAULEY]

phil
while you had the deck off to add a tank did you replace the orginal tank
lot of work to take the deck off also did you put the new tank in the cooler area between the seats
bob

[boatnut]

The biggest consideration when installing any tank be it poly or metal is secure mounting and ventilation in the case of metal tanks. We can argue the merits of platform "vs" foam, foam gives the best support eliminates flexing and adds structural integrity to the boat. If platform mounted the bottom must be well supported from end to end to eliminate flexing, it must be secured in a manner not to allow any motion what so ever. A tank without proper bottom and side support is surely doomed to early failure! In all cases the compartment must have good ventilation and drainage. I think there is way to much ‘To Do" about foamed aluminum tank failures, if you go back over the tank posts the majority of tanks being or having been changed gave many years good service. Some around 30 years far more years then most will ever own their boats.
To answer Joe's ? "Phil, what year is your 22, and what size tank did it take?" Its an 86 like George said I added a 40 gal tank directly behind the original. The original tank is fine, I just wanted to move the CG aft which I believe worked well as I use far less trim at speed.
Phil

Good points Phil, a few questions please:
1) In your opinion, assuming one could provide a perfect platform between the bottom of the boat and an RDS alum tank (e.g. a flat surface that matched the tank with foam between this surface and the boat bottom, including a PVC pipe in this area to take bilge flow through this area), would it be better to platform mount the tank (on rubber strips??) where most of the tank surface would be venilated as opposed to foaming in the entire tank?
2) Do you have a feel for how many removed tanks (from Donzi's) were actually leaking as opposed to showing crevice corrosion? Mine is 36 years old with no leakage signs yet.
3) Do we know of any Donzi gas tank caused explosions? We had an event on our lake last year-- a 70's era Hornet or GT had an explosion that blew off the hatch and burned around the engine. Two adults and a child in the boat were not injured. I haven't been able to talk to those involved to see if they know the cause (tank or other leak??).
4) And lastly (I probably should make this another thread as I do not want to change from this excellent discussion on gas tanks), I was surprised to find you wanted to move the cg back in your 22. I have a 22 with a 454/Bravo and at first glance the boat seems stern heavy. I was considering adding some old Mercruiser racing afterplanes I have but was concerned about adding more weight. I need almost full trim at mid speeds to stop porpoising (which may be a prop issue). Any comments?

Thanks for your continued experience sharing. Ed

[MOP]

I prefer foam for simplicity and strength, Most non foamed bilge mounted tanks do not have the compartment bottom sealed but have fair sized limber holes to allow water to get out easily and to help with air circulation. No matter which way you decide to go do your home work, coat it well and mount it tight in a well ventilated compartment. If you use rubber make sure to use sythetic, "real" rubber, real rubber has proven to be corrosive.
The majority of the tanks I have seen were pitted with quite a few from the top, failed seams were mostly on platform mounted ones.
My 22 has a mild 383, I know getting the weight aft improves speed. I do not think the 383 makes much more HP then the Tempest it replaced, but I am 4 miles an hour faster and require a lot less drive trim. I also switched to a Bravo drive which I have been told steals about 2 MPH. I am more then happy with the results, it matched or exceeded what I wanted from the boat, full tank and just me 65+ is a given, 45 cruise and very good economy.
The 22 for the most part can get away without tabs, mine did not have tabs but by adding the 12X12's it gave me the added control for seas conditions and passenger weight changes. I feel any planing hull benefits from tabs being able to control ride attitude. But face it we spend most of out time at a high cruise it is sweet to be able to fine tune it. No argument many have cured porpoising with the right prop. At WOT tabs UP trim Out!

Phil

[gcarter]

excellent post George!
now i want some foul, evil smelling black goop............. enough for a 32 gal. tank (plus a little)
I just looked up what I paid for five gallons.
One gallon would be $55.00 plus shipping. Let me know. My email addy is below.

[Rob]

When I pulled the original galvanized tank out of my sixteen after almost thirty years, the problem was not the tank. It was all the rusty, dirty crap that had been pumped into the tank from marina's that didn't filter their fuel. The spin on filter certainly keeps it out of the engine, but if it ends up clogging the pick up tube in the tank, you are still screwed.

I still have the tank in my attic. After I washed it out and cleaned it up, it could have easily gone back in the boat. There was very little rust on the outside or the inside of the tank. All of the seams were tight.

It was extremely heavy however. For what I had to pay to Florida Marine Tanks to get an aluminum version, it seemed like a good deal so I went for it.

I now have a funnel with a brass screen that I use when I fill the tank. Although by no means a big problem, I am still surprised what I catch in that screen in the way of crud, even from land based gas stations.

[Tony]

Below is what my tank looked like when I pulled it out after 37 years. The joint where the PVC tube met the aft bulkhead was compromised, allowing water to soak the foam. This slowly corroded the tank from the outside. As I scraped the foam off the tank it was literally dripping wet with gas!
Inspect a tank carefully...the top 4 or 5 inches of foam was bone dry prior to removal. Further probing and, of course, a telltale odor indicated it was time for a deck-off tank replacement project.

[gcarter]

The pipe is another subject.
My '86 Minx pipe was mounted in double sided tape, which didn't do much to seal at all. I replaced the sch 40 3/4" pipe w/ a 1' thinwall pipe like they use in irrigation systems.
1) This more than doubled the area of the pipe for much faster draining.
2) I increased the hole size in the bulkheads to 1 3/8" with a hole saw. I epoxied the new pipe in, no leakey again!!!

Anything simple like this you can do to improve your boat, you should do. There's almost no expense involved.

:wavey:

[gcarter]

Good points Phil, a few questions please:
1) In your opinion, assuming one could provide a perfect platform between the bottom of the boat and an RDS alum tank (e.g. a flat surface that matched the tank with foam between this surface and the boat bottom, including a PVC pipe in this area to take bilge flow through this area), would it be better to platform mount the tank (on rubber strips??) where most of the tank surface would be venilated as opposed to foaming in the entire tank? Ed
Ed, the problem is the complexity of the inside shape of the hull. The tank is kind of like an airplane wing design where the tip shape is defined, the root shape is defined, and the in between area is whatever corresponds to the position between the two defind sections i.e., there is the "front" of the tank, which is a six sided shape of a particular size, the rear of the tank, ditto. in between are six flat plates, four of which change widths continuously. That's complex enough, but then to build some sort of support system in a totally undefined, constantly changing void.
I guess you have to be there.....

[MOP]

George is right doing a hard mount in our odd shaped bliges is more work to get it right. Foam is simpler and provides bottom, side and end support to eliminate any flexing also adds some rigitity to the boat. To me the simplest answer to foam is how long it lasted in the first time around, more then likely with lesser grade foam and little no coating. Kind of a no brainer!!!

Phil

[mattyboy]

Tony,
I had one looked just like it I think Jamie's got it now, my pvc pipe was not damaged. Mine just had no way for the moisture that gathered in the tank compartment to leave that compartment so it sat and stewed in it's own juices

[gcarter]

FWIW, this is the RDS drawing of the stock 41 gallon alum. tk......

http://www.donzi.net/forums/attachment.php?attachmentid=4762&d=1090533577

For those that haven't seen one of these yet, it gives you an idea why it is so difficult to build a hard support.
Also notice it is .125 thick, not .090 which is better according to the USCG piece I posted in #2.

[boxy]

George is right doing a hard mount in our odd shaped bliges is more work to get it right. Foam is simpler and provides bottom, side and end support to eliminate any flexing also adds some rigitity to the boat. To me the simplest answer to foam is how long it lasted in the first time around, more then likely with lesser grade foam and little no coating. Kind of a no brainer!!!
Phil

So Phil/George/Foamy guys, if you take the time and do it right, isn't a hard mount superior to a foam mount ?

[boatnut]

I hear all of you on the complexity of providing a platform for a complex shaped tank sitting on a more complex shaped bottom. My thought was to try and use the new tank with some spacers attached and wrapped in plastic as a male mold. This could be mounted in the proper position and then enough foam poured in to support the bottom and go up the sides an inch or two. When the foam cures the tank could be removed and the carefully coated tank could then be reinstalled to sit on the foam with some rubber spacer strips or something --- it was just a conceptual thought to get air around most of the tank. The fact that my current tank has been in there for 36 years and doesn't seem to leak is also a good point and vote for the simpler method of foaming the tank in. My tank is the older (25 gal approx) style so I am not sure of the shape of it. My boat has led a pretty protected life (not that that makes any difference with crevice corrosion) so at times I think I should watch for sight/smell clues of leakage and just leave it alone until it fails -- but I guess that is not the cautious path. George, this is probably a dumb question, did you find that epoxy adhered well to pvc? I have never tried it. I was thinking of securing the flow-through pipe under the tank with 5200, but your epoxy method is probably better.

[Lenny]

George, what a NICE little .pdf tidbit that above post is :yes:

Thanx

[MOP]

So Phil/George/Foamy guys, if you take the time and do it right, isn't a hard mount superior to a foam mount ?

Steve that is a good honest question!

If done correctly both are very good but depend upon the application, in higher performance boats it becomes far more critical to make sure you have absolutely no motion. A platform or cribbing type mount is like George said is complicated by compartment shape and it must be done very well, in a high performance boat the tank must have side, end and bottom support to eliminate motion which will cause flexing of the tank any flexing. The most important thing to achieve in any tank installation is -0- motion under the pounding loads we give our boats, any motion will transmit to the tanks surface and work harden the metal which will eventually crack. The proof of foam being superior is well proven just on this one site, the biggest complaint about removal is how tenaciously they are still stuck in the bilges of very old models.

Foam tanks can be removed quite easily doing the following!

There is about ½" or better gap around most all foamed in tanks. everyone tries to cut around the tank with thin blades of some sort and still it a :cussball: to break free! The foam needs to be cut out so as to allow the tank to be pryed side to side!

To accomplish this take a long enough piece of steel bar stock to get down to the bottom, it should ½ wide at least 3/16" thick 1/4" is better. Bend a hook into the end and sharpen the edge, use the bar stock like a hoe to dig out the foam all the way around the tank. Once you have dug out the foam take a pry bar and pry the tank side to side that will break the foam loose under the tank it will then lift out effortlessly.

Pardon some of the above rambling's! Bonnie is on the war path with "Honey Do's" Back to work:sombrero:

Phil

[MOP]

I hear all of you on the complexity of providing a platform for a complex shaped tank sitting on a more complex shaped bottom. My thought was to try and use the new tank with some spacers attached and wrapped in plastic as a male mold. This could be mounted in the proper position and then enough foam poured in to support the bottom and go up the sides an inch or two. When the foam cures the tank could be removed and the carefully coated tank could then be reinstalled to sit on the foam with some rubber spacer strips or something --- it was just a conceptual thought to get air around most of the tank. The fact that my current tank has been in there for 36 years and doesn't seem to leak is also a good point and vote for the simpler method of foaming the tank in. My tank is the older (25 gal approx) style so I am not sure of the shape of it. My boat has led a pretty protected life (not that that makes any difference with crevice corrosion) so at times I think I should watch for sight/smell clues of leakage and just leave it alone until it fails -- but I guess that is not the cautious path. George, this is probably a dumb question, did you find that epoxy adhered well to pvc? I have never tried it. I was thinking of securing the flow-through pipe under the tank with 5200, but your epoxy method is probably better.

My pipe had to be joined to the exsiting one under the original tank, I was unable to use a coupler so I took care to make long ajoining tapers one in and one to insure a good fit used 5200 to join and mount the tube followed by 2 layers of glass over it sealing it completely.

Phil

[Donzigo]

My fuel tank changing story:

Two years ago, I changed out the 200 gallon fuel tank in the 33 and installed a 140 tank. The 200 gallon tank was made in 1989 of 1-8 inch aluminium. That would be illegal to use such a thin material for such capacity; and, was possibly borderline illigal then. The old tank was measured by my fuel tank manufacturer, it was slightly less than 1/8 inch and was made by the same people that made George's new tank. (Perry, Florida). No fault of theirs, they make whatever the manufacturer wants. I went to a 140 gallon tank; because, it didn't make much sense to have such a large capacity, given my boating and unless somwone is fishing, I don't understand why a 200 gallon tank would be necessary in a 33 - Donzi anyway. Oh, I also changed the valves to be stainless and larger than the original. I had JTR, here in St. pete, paint it white with primer underneath. I had large tabs built on the tank, two on each corner, top and bottom, a total of 8 tabs with three hole in each tab. I drilled into the huge 4 inch side stringers on both sides and put 24 stainless steels bolts with 4 nuts and washers on all sides of each tab, thus making the mounting stable from any type of movement. I used 1/2 inch thick rubber, (Donzi original was wafer thin) and put 8 rows of rubber, twice as many pieces as the original 4 rows. I used no foam and got rid of the PVC pipe. I now have flow through water from the front compartment to the back right into the engine room. It's not that way they do it at the factory; but, I'm told that race boats do this sort of installation, so I did it that way and I am OK with it. I recently checked everything by taking the hatch off, after the two year annviversary. Everthing is perfect, just like it was the day I installed it. My guess is that at the factory, my installation would take a enormous amount if time, and be far more costly. I've had two boats that I changed the fuel tanks, a 25 and 33. They were both beatiful inside and out, until I looked at the outside of the bottom. OMG, am I glad I changed them. Corrosion city. On the 25, I went back with the foam and the 33 got tabs. I like the idea of tabs better.

My 2 cents.

[sweet 16 1966]

I also had the Perry Fla folks make me a 25 gal. tank in 85 which I changed in
2004. It was close to pitting through. I wonder if Donzigo's padded installation will last longer. What is it, moisture without the presence of oxgen causes corrosion? Why can't they use a closed cell foam creation to prevent this or is it not available?