21GT gas tank replacement

[Danny]

Have to do this, so who has done this ? Any pictures?
I have followed Nate's rebuild (great job)
I just want to do a quick in and out.
The same as the 16 but only on a bigger scale?
Any input would be appreciated.

Danny

[Lenny]

I just want to do a quick in and out.

Yeah, and who doesn't ? :D

[Donzigo]

Well, changing out a fuel tank is like this............you start by taking the screws out from around the edge of the top cap, you find a hoist, crane, or some strong friends and you take the cap off................and then you see where it leads you.............right George Carter ????

If your boat begins to smell like fuel or is over 10 years old, you should be thinking "new fuel tank". OK, OK, I know some will beat me up for the 10 year number; but, I'm sticking ot it.

Richard

[Ted Guldemond]

I'm not so sure you need to pull the deck to get the tank out. I've looked at mine in anticipation of the same delema. I'm probably wrong but I would first pull the engine (much easier then removing the deck), saw out the 1/2" thick plywood framing between the stringers, separate the tank from foam & stringer, then pull the tank aft (either pry or use a come-along). Even if the tank is too long to remove aft, after emptied flushed and ventilated it could be sectioned to complete removal. It my require a different size/ shape going in but in my mind and limited work space might be an easier fix?

[mrfixxall]

I would first try to find the leak first..I have a 77 x18 with the oe tank in it..My leak was coming from a combination of the fuel sender(the old cork gasget fell apart from age) and my over flow hose was dry rotted ..Now no more leak....I have also found that some sending units will fail..(im my cust boats)

[gcarter]

IMHO, with the original wiring and plumbing, it's easier to remove the deck.
Also, I'm not sure how you could re-mount the tank from the rear. It would certainly be nearly impossible to re-foam the tank in.
Just for reference, take a look at;
http://www.donzi.net/forums/showthread.php?t=36420&highlight=tank

and

http://www.donzi.net/forums/showthread.php?t=36703

[Lenny]

Ted, for what it is worth, I think I agree with you to a point. When I had my GT21 I thought the same thing. Pull the motor and slide it out the back. BUT, I do not know how long the tank is, I do not know if it would pull up and out through the engine hatch and clear the forward engine hatch area, and as for securing again once a new on is in, how woulkd you manage that?

I think the deck off is the right way to go about this, and makes for re-plumbing ease and correctness, and re-foaming or however you re-fasten the tank in there can be done properly.

I vote for deck off.

[Danny]

There are no leaks, mine is a comtamination problem from too many years of not a lot of use and the galvinization breaking down in the tank. It's been emptied, flushed, tried different additives, polished the fuel and the problem persists. Even with a fuel seperator and inline fuel filters I still have problems. I finished the season running on an outboard gastank that I rigged up.Time for a new tank.
Looks like the deck is coming off, I think it would be extremely difficult to get the old tank loose from the foam while still under the floor.
I have had a couple of people suggest cutting the floor(mostly under the rear seat) but I just cringe at that option.
My 16 had fiberglass tabs between the stringers and floor beside the storage locker, are there any places on the GT that are glassed together or just the deck screws?
Stainless, aluminum or plastic?
Leaning toward stainless, having it custom made in a local shop that does a lot of marine work.
thanks Danny

[Lenny]

Danny, the 21 has glass tabs as well. Along the stringers and forward area. Same as a sixteen only more. Then again, it depends on the mood of whomever put it together as there have been variances before.

[Donzigo]

Take off the cap...........you'll be glad you did.

[Rob M]

Cream boat, brown stripe. Brown interior. 350 Corvette engine?

[gcarter]

There are no leaks, mine is a comtamination problem from too many years of not a lot of use and the galvinization breaking down in the tank. It's been emptied, flushed, tried different additives, polished the fuel and the problem persists. Even with a fuel seperator and inline fuel filters I still have problems. I finished the season running on an outboard gastank that I rigged up.Time for a new tank.
Looks like the deck is coming off, I think it would be extremely difficult to get the old tank loose from the foam while still under the floor.
I have had a couple of people suggest cutting the floor(mostly under the rear seat) but I just cringe at that option.
My 16 had fiberglass tabs between the stringers and floor beside the storage locker, are there any places on the GT that are glassed together or just the deck screws?
Stainless, aluminum or plastic?
Leaning toward stainless, having it custom made in a local shop that does a lot of marine work.
thanks Danny
I see you're from Cannuck Land....here SST and 'glass tanks are illegal for gas.
The only options you have are an aluminum duplicate, or a similar size plastic tank.
Tabs are over rated, remember, they were pieces of scrap. Also cockpit floor support is almost non existant. You might want to note how I solved both these problems.

[Danny]

Rob that would be the boat.
Where do you keep your boats?

George what's the rational for not allowing stainless tanks?

Thanks Danny

[Rob M]

Rob that would be the boat.
Where do you keep your boats?


Danny: On Lake Rosseau...sleeping soundly for the winter. Good luck with your 21GT.

[Danny]

Rob do you know more about the history of my GT. I tried to find the previous owner to no avail and no one at Magregor's new anything.
Danny

[Rob M]

Rob do you know more about the history of my GT. I tried to find the previous owner to no avail and no one at Magregor's new anything.
Danny

Hi Danny: Not really, sorry. I remember it was in BoatTrader on several occasions before it was auctioned off, listed in BT by a Marina - originally it was at a location farther up Hwy 11, closer to the water. I'm pretty sure it was a local boat (Simcoe/Couch) for a long while - perhaps always. If I recall correctly from talking to the marina when it was listed, the previous owner had it for a long time and traded it into them for a newer upgrade - but that could just be a BS sales story. When I looked it over thoroughly prior to the auction it was all original with hull/engine numbers matching, about 900+ hours if I remember right? So it wasn't likely traded around and messed with too much - just had the ski holder cut out as I recall.

[Danny]

Rob
There were two McGregor locations, one on the water just north of their dryland loctaion , both on hwy 11 just north of Orillia.
You are right the original owner traded it in and it was used by the sales guys at the waterfront location but ended up in the auction at the other site.
I looked at on several occassions and made a couple of offers on it over the years and ended up getting it at the auction.
Danny

[Rob M]

Hi Danny

The stories match - that's good. I'd keep hunting down the owner - someone will know him.

If you're overhauling with the deck off that's not a bad time to consider changing the colour if you don't like brown. Good luck with the 'lift'!

Rob

[Ted Guldemond]

I agree the best way to replace the tank is to pull the deck. I dont recall the length of the tank. If it wasn't shrink wrapped I'd go measure it. Re: wiring & plumbing, the sender and siphon are accessable from the engine compartment. I changed the sender last year. The fill and vent tube are difficult but reachable through the bow. In fact there is considerable room forward of the existing tank to put either a longer tank or a second tank. I have gotten in there myself (195' on a good day). With regard to foaming the tank in, you might want to check a web site Yachtsurvey.com. The author is quite opinionated but has many good ideas. including is short how to on tanks. Look under his maintainance section. There are many excellent threads on gas tanks here, as mentioned above. Again I agree pulling the deck certainly gives you the most access and ability to do the million other unexpected problems. But if all you want is to change tanks I thought it might be an option.

[BERTRAM BOY]

Danny,
For the love of God.... don't cut any bulkheads!!!!! You most likely wouldn't be able to get the tank out afterward if you did. the foam is too strong (yes Phil, I said the foam was too strong) for you to pull it out.
The best way is to pull the deck.

If you do a search on "deck lifting" and/or gas tank, I'm sure you will find plenty of info.

Here is one of many.

http://www.donzi.net/forums/showthread.php?t=23152

[gcarter]

George what's the rational for not allowing stainless tanks?
Thanks Danny
Danny;
Here's the reason;
"Stainless Steel

The UL report indicates that some boat owners chose stainless steel as the material for replacement fuel tanks, since this material is obviously "stronger" than aluminum; however, it is also susceptible to pitting and crevice corrosion in the marine environment, although at a different rate than aluminum. Stainless steel is also susceptible to stress-corrosion cracking and is even more prone to that type of failure at weld areas.

Only the 316L stainless steel alloy with a specified minimum wall thickness of 0.031 inches is considered suitable for use in the construction of marine fuel tanks. American Boat and Yacht Council standards ANSI/ABYC H-24, ABYC H-33, and ANSI/NFPA 302 all require stainless steel fuel tanks to be less than 20 gallons in capacity and cylindrical with domed heads to limit the wall stresses experienced in service.

While the uninformed boat owner who happens to construct a small capacity rectangular tank may be lucky enough to avoid a failure due to stress corrosion cracking; some boat owners who participated in the UL study spent considerable amounts of money to have replacement tanks constructed to capacities as high as 150 gallons. Many other boat owners who were surveyed mentioned that, on a cost independent basis, they would have preferred to have used stainless steel for their replacement tanks. "

However, being a Canuck, you apparently have an advantage;

http://www.tc.gc.ca/marinesafety/tp/tp1332/section7.htm#gen7-1

[Ted Guldemond]

No matter how you take the tank out, the foam is a minor problem. Take a hand saw (crosscut or rip). Saw throught the foam, sides and bottom. Use a keyhole saw on the corners. I pulled a 60 gal tank on my St. Tropez without a hernia. By the way BertramBoy, God has nothing to do with it!

[Tony]

Here's another vote for the deck-off process:

Deck-off Day 1
http://www.donzi.net/forums/showthread.php?t=35831

Deck-off Day 2
http://www.donzi.net/forums/showthread.php?t=36114

Deck-off Day 3
http://www.donzi.net/forums/showthread.php?t=36402

[BERTRAM BOY]

No matter how you take the tank out, the foam is a minor problem. Take a hand saw (crosscut or rip). Saw throught the foam, sides and bottom. Use a keyhole saw on the corners. I pulled a 60 gal tank on my St. Tropez without a hernia. By the way BertramBoy, God has nothing to do with it!



Ted,
You're right foam is a minor problem.......if you take the deck off.

As far as the God reference is concerned, It's an expression. Get over yourself.

[hardcrab]

i am currently smack dab in the middle of this deck off / tank replacement also. ( slooooowly but surely )
this question is being asked after the fact but, i've had a replacement tank made (by RDS mfg.) that is larger in all dimensions. the foam surrounding the original installation was several inches thick; i now have 1+" space which to re-foam.
is there an issue in strength, or is the primary intention of the foam to secure the tank?
thanks for any opinions or experiences
(mine is a 1966 18' 2+3):crossfing

[gcarter]

Don't worry, the foam does it all.
It actually becomes an integral part of the boat.

[mattyboy]

the biggest problem we had was with the foam on the bottom of the tank, the bulk heads don't allow enough room to get a saw blade under the tank and normal keyhole saw aren't deep enough and a full length cross cut hand saw isn't flexible to follow the angle of the hull , in hind sight maybe a piece of piano wire with two wood blocks could have been worked under the tank then pulled thru between the bottom of the tank and the foam??( I got that idea last night watching the godfather when they whack Luca Brazzi)

Hey Cliff thanks for posting that link, now i'll have to start up therapy again :p ;)

[gcarter]

Your tank was steel, right Matty? And pretty rusty? If so that could be why.
Mine almost came out on its own after I sawed out the shallow end.

[thecore]

Ted,
You're right foam is a minor problem.......if you take the deck off.
As far as the God reference is concerned, It's an expression. Get over yourself.
Hey Bertam BOY, Your the one that needs to get over yourself. From reading Ted's post, he is obviously experienced and very smart. By the time you boys rip the deck off and replace the tank, Ted would be out on the ocean and living large. Leave your ego at the door and fallow the master.

[mattyboy]

Leave your ego at the door and fallow the master.
along with your brains and spell checker????

[hardcrab]

Hey Bertam BOY, Your the one that needs to get over yourself. From reading Ted's post, he is obviously experienced and very smart. By the time you boys rip the deck off and replace the tank, Ted would be out on the ocean and living large. Leave your ego at the door and fallow the master.
so, do YOU have any USEFUL input or ANY experience?

[BUIZILLA]

fallow the master.dum-dum-dum-dum-dum-dum.....

fallow: adj ; plowed but left unseeded during a growing season ; characterized by inactivity ; to plow and till, especially to eradicate weeds

now, why would BB want to fallow, plow, unseed and eradicate the master?

unless, of course, BB wants to remain seeded, and intellectual

ahhh, the ENGLISH language is such a wonderful tool to change the tides

:alligator

[BERTRAM BOY]

I love it when my buds are watching my back.

[Greg Maier]

Yes, it does seem like "Ted Guldemond" and "the core" are good friends and tend to pay compliments to each other ! See the thread below:
http://www.donzi.net/forums/showthread.php?t=41206&page=2

[Ted Guldemond]

Let me start this reply by first apologizing to Danny. I'm sorry your question on gas tanks got hijacked. What I have to say now, I do so without intentional malice, nor is it focused at any individual. I am truly surprised that in a forum designed for the sharing of information and ideas, that the participants would resort to personal attacks and insults. If I have offended anyone it was not my intention. I feel a better way to reinforce a position is with explanation and discussion. Put-downs and personal attackes will not bolster an opinion any further than hyperbolic "verbal expressions" and hypertrophic punctuation. Impugning someone's argument because of spelling errors is also without merit, as there are many informative posts on this site riddled with typos. I'm sure you noticed I stopped replying when the discussion turned negative. I only reply now because of the character attack. As to the speculation re: "The Core", he is indeed a good friend and his own person. I do not speak for him, or him for me. There is no attempt at deception. We both post from the same small town in Mass.-not hard to conclude we know each other. As to the referenced quote from earlier this year. When that was posted I did not know that was my friends pseudonym until we talked a few days later. In closing I appreciate all the wisdom the particpants of this board have imparted over the years. They have made my restoration projects much easier. So feel free to beat me up now, but at least be civil about it.

[TuxedoPk]

Ted,

"I am truly surprised that in a forum designed for the sharing of information and ideas, that the participants would resort to personal attacks and insults....Put-downs and personal attackes will not bolster an opinion any further than hyperbolic "verbal expressions" and hypertrophic punctuation."

If you've been following the board for any length of time you'd realize that the position of using big words, personal attacks, and insults is already filled and quite competantly I might add. :wink:

Cliff- Never would have thought to watch your back... I've never seen an arrow flying in your direction before :)

[joseph m. hahnl]

NOW: NOW: We all go at it. I get my fair share of criticsism too..But it's all in good clean fun. That said: there is an old machinist saying"Hurry up and **** it up" this is usually said by the boss because he is so impatient he'd rather have you make something twice instead of taking the time to do it right the first time. any way it all comes down to time.How long it takes to do the job. At some point we all have to do a tank replacement.There are many here who have proven the method and more or less set a standard for tank replacement.In some cases there is no short cut to success and this would be one of those ocassions.Take the time to do the proven path"Remember the Donner Party"short cuts usually imply laziness and always end up taking longer.

It is easier to turn a screw driver than to saw thru anything. It is amazing to me that Donzi made it so easy to take the deck off. why would you want to do it any other way?

joe

[Donzigo]

Well said, Jopseph.............how's about someone who has done it (not me-Z33's aren't easy to take the top off), tell Danny exactly how long he should expect this "top-off" process to take...............George?, other's.....I know there have been many who have done it.

Seems like a fairly easy thing to me...........so, what's up with all that sawing foam from the back, etc. etc.?

As for personal attacks............comes with the territory in Donzi country, partner. Keeps us all awake through the winter. Heck, we haven't had a good discussion in a while about other controversial issues........windsheild/no winsheilds, types of oils, etc, etc............oh no, here I go stirring it up....

[mattyboy]

Donzigo
very true ;)

the top off process lasts as long from a weekend ( 3 day) to weeks depending on what is being done, now in my case there was an unforseen repair that excalated my project into weeks someone had glassed the hull to the deck along the port side rail of the boat from the throttle to the bilge , and we took advantage of having the top off to repair replace all the stuff I can't get to when the top is on starter bilge pump ,impellor also painted the bilge.
The best advice I can give is expect the worst, from bad stringers to finding dead things in there this way when it is not that bad you feel better I went from a quick in and out to having the 2 halves of my boat in two different states!!, have a good support system the guys who helped me were GREAT I can't thank them enuff, have plenty of beer pizza and cash ;) and a camera on hand, just remember the old addage about projects it will take twice as long and cost twice as much ;)

and always remember why you are doing this to make your Donzi better
and I plan on being around when the deck gets popped on Scott's benchseat hornet just like I was there for Cliff's 16

:)

[Donzigo]

LOL.................DEAD THINGS.................like what kind of dead things?

[Danny]

Ok
Deck off
Coated aluminum tank
Foamed in

I have access to the shop at work that has phenomenal lifting equipment so the deck removal may actually be almost fun in a sick sort of way. However I would like to be in and out in a weekend. Get to the shop with everything ready to lift the deck off, cut the old tank out, new tank foamed in and the deck back on.
Overall condition of the boat is very good and my tank problem is from lack of use and interior deterioration of the tank not corrosion or leakage so I don't anticipate any other issues.
Already had the motor out , new transom, bilge paint ect.
I have a pretty good idea of the shape and size of the new tank but does anyone have the exact dimensions, length and width are easy but looking for depth and shape of the bottom. I assume the bottom of the tank follows the contour of the hull with a flat surface in the bottom to accomodate the waterraceway in the very bottom.
I really would like the new tank fabricated and ready to go.

Thanks Dan

[gcarter]

Wasn't anyone around to help me. I had to figure out ways to do it all myself.
Mine was off about three-four months.

[Rob]

I did mine solo too. It's very possible, you just have to be a little more creative. I also had the luxury of a spare space in the garage over the winter.

If you had all the parts lined up and nothing went wrong, you could do it in a weekend. I wouldn't bet on it however.

[Marlin275]

I have a pretty good idea of the shape and size of the new tank but does anyone have the exact dimensions, length and width are easy but looking for depth and shape of the bottom. I assume the bottom of the tank follows the contour of the hull with a flat surface in the bottom to accomodate the waterraceway in the very bottom.
I really would like the new tank fabricated and ready to go.
Thanks Dan

You need your old tank as a sample to make the new tank.
Sure you can get plans but you don't KNOW whats in there till you get it out.
I sent my old tank to the metal guys to copy to fit.

[Tony]

Another thought...some guys have added an inch or two here and there, for increased capacity. Carefully check all dimensions, and location, before pulling the tank. (Especially if you have a sight glass guage...don't ask how I know this) If you can swing a slightly bigger tank the extra capacity is helpful.