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Sweet Cheekz
05-23-2009, 08:11 PM
can I assume that a gt21 is slower than a 22c? What is the highest speeds and power combo's that get one running? Thanks
Parnell

Donziweasel
05-23-2009, 08:26 PM
Donzi Gt-21's were made in single engine configs and a few twins w/350's. Seen some big singles. Cool boats and although stock they were not near as fast as a current 22, they can go fast with the right power/drive.

It is a heavy boat. Will take some BIG power to go really fast and that means big $$$$$$$.

BUIZILLA
05-23-2009, 08:34 PM
it's very doable.. :yes:

gcarter
05-23-2009, 08:53 PM
There's a member in Tampa that has just about finished beefing up the hull of a GT, including a 509 BBC. He's lost interest and it's in storage. He made a comment once about selling it.

Lenny
05-23-2009, 09:15 PM
There's a member in Tampa that has just about finished beefing up the hull of a GT, including a 509 BBC. He's lost interest and it's in storage. He made a comment once about selling it.

Wouldn't be our friend in Naples would it ;) ???

I had one, never got it out, then sold it. 351's were the twin version. Had ride angle quirks and running issues apparently. That is a LOT of motor for the back of a 21 foot boat. Might be better off to shave 900 pounds off and just lighten up and then go grab another 300 ponies in a single. These are a 400-450 horse boat minimun to have fun in my opinion, and then some.

Beautiful tho, to say the least if the windshield is somewhat in tact...

mattyboy
05-23-2009, 09:21 PM
the gt is really from a different era it started in the late 60's and ended it's career just about the time the 22 criterion was introduced which was the start of what we know as the 22c a warmed up late model 78 ish gt with a 454 and trs ran mid 70's just about the same as a 22 hull with the same setup


I don't know of any twin 350 boats but twin fords were made 302's and 351's usually mated to volvo I/O's they did make one twin 427 side oiler v drive gt as well as single engine v drives and jet drive these were usually earlier models before the BB and the trs drive came about

but with the higher freeboard and higher sides, the rounded keel and deep vee it is a great platform to start with not to mention it is almost 800lbs lighter in a single setup than the early 22's ;)

olredalert
05-24-2009, 12:18 AM
-------Matty,,,They made at least one with a #3 Speedmaster/427HO GT21, and they made mine with a standard #3/low HP 427. I dont think they were the only ones but I never saw any others. The Speedmaster one apparently ended up in Texas and Conquistador actually owned it, but I think DONZI took all the good stuff out before delivering it to the second owner. The first owner was a very close friend of John Chisholms. The same guy owned one of the twin Holman/Moody GT21s before the Speedmaster boat. One of the biggest problems with at least the 1st twin H/M twin boat was a single 3/8ths gas line to feed both motors if I remember correctly. I road in both boats at one time or another and both performed well but the Speedmaster boat was about a 75 or so MPH boat which trumped the twin pretty easily. That was real fast back in that period!!!!!!!!...........Bill S

Lenny
05-24-2009, 01:23 AM
Bill, I love your stories and the past that you were a part of :yes:

:)

superhatz
05-24-2009, 01:27 AM
-------Matty,,,They made at least one with a #3 Speedmaster/427HO GT21, and they made mine with a standard #3/low HP 427. I dont think they were the only ones but I never saw any others. The Speedmaster one apparently ended up in Texas and Conquistador actually owned it, but I think DONZI took all the good stuff out before delivering it to the second owner. The first owner was a very close friend of John Chisholms. The same guy owned one of the twin Holman/Moody GT21s before the Speedmaster boat. One of the biggest problems with at least the 1st twin H/M twin boat was a single 3/8ths gas line to feed both motors if I remember correctly. I road in both boats at one time or another and both performed well but the Speedmaster boat was about a 75 or so MPH boat which trumped the twin pretty easily. That was real fast back in that period!!!!!!!!...........Bill S

Bill...was that a 427 Chevy....Mercruiser?

superhatz
05-24-2009, 01:28 AM
the gt is really from a different era it started in the late 60's and ended it's career just about the time the 22 criterion was introduced which was the start of what we know as the 22c a warmed up late model 78 ish gt with a 454 and trs ran mid 70's just about the same as a 22 hull with the same setup
I don't know of any twin 350 boats but twin fords were made 302's and 351's usually mated to volvo I/O's they did make one twin 427 side oiler v drive gt as well as single engine v drives and jet drive these were usually earlier models before the BB and the trs drive came about
but with the higher freeboard and higher sides, the rounded keel and deep vee it is a great platform to start with not to mention it is almost 800lbs lighter in a single setup than the early 22's ;)

Twin side oilers?....really?

superhatz
05-24-2009, 01:31 AM
I stole this photo from somebody....:)

Is this the side oiler boat?.....H&M decal and v-drives.....

mattyboy
05-24-2009, 06:10 AM
Bill,
great info, I recall the fuel issue too with the twins it was brought up when the blue and white one was redone. I always look at the GT as a bridge from the past to the present for Larger Donzi. the 16 and 18 never really changed much mostly SB power and volvo then SB power and merc although they did make a few BB boats.

The GT on the other hand had the room to add power like the 22. Unlike the 22 that came in with BB merc power (trs) the GT started in the early days before the volvo was really proven to handle BB power . so if you wanted a fast gt you needed more HP so add an engine . I bet if you look the twin boats are earlier models. then as power and drives improve the BB and merc boats come around which were lighter faster

the really nice blue and white Lake George GT that sold recently was a 454 trs boat warmed up it was a 75 mph, wish I had the ching I bet if you treated a Gt to a revamp like some of the faster 22 here are getting you'd find they are just as fast.

Bill is the X Dim. an issue on the GT???? are they a little low like the early volvo 16 and 18's ???



Super yes twin 400 hp HM 427 side oilers not sure if that is the boat or not but i bet i would look something like that :cool:

BigGrizzly
05-24-2009, 08:31 AM
What Poodle didn't show was the old Corsican chasing him down and blowing bye bye. Another piece of information was the 427 side oilers were 300 HP. and the V drives in that boat were slower then the same power in out drives. Another overlooked fact is one 600 HP engine is faster then 2 300 HP motors, especially i n smaller boats under25 feet approximately. Trust me we have done this comparison many times both on OBs and out drives too.

mattyboy
05-24-2009, 09:09 AM
Grizz not sure of the actual HP ratings but they sold a 300hp and a 400 hp 427 option from the factory
the famous SS barrelback V drive that was assigned to the LBJ detail was a 400 hp option

I agree in a under 27 foot boat one big HP motor will be faster than two motors that make the same HP as the single high HP motor well in an I/O or v drive anyway seems with today's eggbeater you get more of a thrust to weight ratio so adding 300 hp doesn't mean adding all that much weight

BigGrizzly
05-24-2009, 09:21 AM
Trust me on this, we have had the 400 H&M, very limited production, on the dyno and 400HP was a way over stated power. the 300s were just shy of 290. These came in a month and a half ago for rebuilding.

olredalert
05-24-2009, 09:27 AM
------Thanks for the props, Lenny. It has been a fun ride!!!
------Its funny but I had never heard of that twin V-drive 21GT except on this board. I would like to see how far under water the boot stripe is on that one.
------Back then I dont think I had a clear idea about X-dimension. I can tell you now that all those early NO.3 and TRS boats had the X way too low. They handled really well but lacked alot in the upper speed ranges. I am raising the X up two inches on the Spitfire and could probably raise it more but I still want a nice cruise.
------Having seat time in both 21GTs and 22 classics, both with similar but not the same power, I can say that the 21GT with its higher freeboard is a drier boat. Actually, I dont see much difference in actual ride, however my 21GT with 427 Chev/NO.3 seat time is a long time ago. It would be really interesting to see a side-by-test of a 21GT with 496/Bravo power next to a new 22 Classic with exactly the same power. One thing thats undeniable is that the 22s (of all designs from the Crits forward) were sleeker, better looking DONZIs than the 21GTs. When I saw my first 21GT I dont think I could have imagined a better looking boat, but DONZI managed that quite handily.
------The Corsican V-drive up here on Harsens Island started life as a 427/400 Holman/Moody. Griz, those pics of the 300s look exactly like my buddies Dads old 35 Magnum powerplants back in the late 60s/early 70s.............Bill S

superhatz
05-24-2009, 01:51 PM
I thought there was a 400hp and a 500hp Holman Moody option in the early Hornets.....?

HOWARD O
05-24-2009, 08:51 PM
I thought there was a 400hp and a 500hp Holman Moody option in the early Hornets.....?

Sho 'nuf, according to this price list.

http://www.donzi.net/cat/cat69/price3.jpg

Donzi Racer
05-24-2009, 09:31 PM
I have always loved the look of the GT-21's, and although not my favorite color, this one is a true sleeper. I hear stories of how fast but I will not say because I do do not like being made fun of! MUCH! I will only refer you to the fact that there is no super or turbo charger and it slings a 30 pitch 4 blade prop quite well, thank you. I will let some of the math wizz peoples figure that out, but it seems it would be much faster than the 70's. She is a true beauty! Tom

BUIZILLA
05-24-2009, 09:42 PM
I could own that.. :yes:

Donzi Racer
05-24-2009, 09:45 PM
I could own that.. :yes:

Jim, do the math for me, probably 1.5 gear with a 30 labbed 4 blade. Turning over 5k rpm. What does that give us?

This one is really done up right. Looks like a new penny. WICKED! Something you do not see everyday. Definitely the fastest GT-21 I have ever heard of. Tom

superhatz
05-24-2009, 10:06 PM
Thanks Howard.....:)

MDonziM
05-25-2009, 03:43 AM
I have always loved the look of the GT-21's, and although not my favorite color, this one is a true sleeper. I hear stories of how fast but I will not say because I do do not like being made fun of! MUCH! I will only refer you to the fact that there is no super or turbo charger and it slings a 30 pitch 4 blade prop quite well, thank you. I will let some of the math wizz peoples figure that out, but it seems it would be much faster than the 70's. She is a true beauty! Tom

wow, wow!!! That is a sweet looking GT. You could raise the x-dim as much as you want and still have room under the hatch. I have always loved that model...the add seat room and the extra beam. If you want to divulge the eng I won't laugh. - Marshall

Rob M
05-25-2009, 04:03 AM
Wasn't this boat for sale a while back for a relatively modest price?

BUIZILLA
05-25-2009, 06:30 AM
since i'm contemplating putting a wood floor in the Critter, where could I see this boat, and how they did it? :lookaroun:

did all of the GT's have a slight raised hatch like that?

hmmmm, dry tails too...

I came up with 82 with that prop or 85-86 with a MUCH better prop..

MR MAGOO
05-25-2009, 07:06 AM
[QUOTE=Donzi Racer;514697]Jim, do the math for me, probably 1.5 gear with a 30 labbed 4 blade. Turning over 5k rpm. What does that give us?


Ok, lets play with this a bit. We'll assume that this modified blig block is making hp to 5400 rpm, 1.5 ratio, 30 B1
Given this info, theoretical speed is 98 mph, back out a conservative slip, lets say 13% will give you 85 mph!

No blowers, how many cubic inches?

Cool boat!

olredalert
05-25-2009, 08:00 AM
------OK,,,Since I know a whole lot about that particular GT21 I will try to answer all the questions. The boat was restored/customized right here in Marine City. The work was done well and the boat is very nice, The people who built it arent!!! Over a period of years they schemed and scammed there way thru a huge number of peoples wallets, mine included. There are banks and loan institutions all over the country that have felt their pinch. They are now thankfully severly out of business. FBI is compiling enough info for an airtite case against them and soon (God willing) they will be on the otherside of the bars.
------The boat did get sold at a very reasonable price to a guy over on the Lake Michigan side of the state. He bought it from the bank that had loaned way over what the boat was worth and had repossesed it. The black Legends boat, really just a 24 Squadron built by the same pair, had a similar fate except they managed to snatch the motor out of it and the bank that repoed it found that another bank had also loaned a bunch of money on it. I believe they are still fighting over the remains, probably about 1 20th of what was loaned against it. The motor in the orange boat was changed out several times but I believe it is about 510 cubes and app 500hp. It does pull very well and I believe it ran a bit over 80!!! The boat runs a Bravo redone by Chuck Broeduer the ex-driver of the "Short Circuit" 27 Magnum that is an old favorite of all the St. Clair warriors.
------The raised hatch that you see, Jim, is actually a sunken center of the engine hatch with a fitted pad that matches the paint and is almost flush with the deck. I really liked that idea, and it shows you just how much room there is in the engine compartment of a GT21 as the X dimension was set pretty high on this hull during the resto...........Bill S

Sweet Cheekz
05-25-2009, 02:24 PM
Bill
You are a fountain of info Are there any pics with the cover off? I would love to see that fairing. Do you know what town on the west side? Is the owner on this board or do you have his name? Thanks
Parnell

Donzi Racer
05-25-2009, 04:23 PM
since i'm contemplating putting a wood floor in the Critter, where could I see this boat, and how they did it? :lookaroun:

did all of the GT's have a slight raised hatch like that?

hmmmm, dry tails too...

I came up with 82 with that prop or 85-86 with a MUCH better prop..


I wanted to get the owner to bring this beauty to AOTH and take a few bets on her. I had not ever heard of a GT-21 that would run like this one. Especially without a Charger of some sort on it. I thought I knew a lot about this beauty, but WOW Bill S thanks for the rest of the story. I would like to hear more about all that. Sounds lke a good book. Any way to get more info on all that? Thank goodness the bank got to this one while it was all still there. Not as fast as Mighty Mouse but it is definitely a WORK OF ART similar to Georges X-18.

Jim, if you get a chance send a pm and I will be glad to pass along the info you asked for. I don't think the owner would mind. This Bad Boy is something else. I had heard 90's, but runs 85 mph relatively easy. Enjoy the final pics. If you cannot own the fastest X-18, why not the Fastest GT-21, that I know of anyway? Tom

Sweet Cheekz
05-25-2009, 05:10 PM
Thanks for the pics Tom The fairing looks great. PM'ed you
Parnell

Sweet Cheekz
05-25-2009, 05:13 PM
since i'm contemplating putting a wood floor in the Critter, where could I see this boat, and how they did it? :lookaroun:

did all of the GT's have a slight raised hatch like that?

hmmmm, dry tails too...

I came up with 82 with that prop or 85-86 with a MUCH better prop..

The wood looks awesome. I had a teak floor in one of my boats one time and it was a real attention getter. Hot in the sun, very slippery when wet and needs a bit of maintanence every year for scrating ect but worth it if you like the look.
Parnell

BUIZILLA
05-25-2009, 05:56 PM
www.plasdeck.com (http://www.plasdeck.com)

www.plasteak.com (http://www.plasteak.com)

www.teakdecking.com (http://www.teakdecking.com)

gcarter
05-25-2009, 06:41 PM
I found this product on the new issue of Professional Boat Builder......Cork Decking...probably a lot cooler than a lot of other products. Also a great sound deadener.

Sweet Cheekz
05-25-2009, 07:25 PM
Looks like these get rid of the hot, slippery and maintanence all in one Someone should have told Cigaretter about this.

Sweet Cheekz
05-26-2009, 09:20 PM
Talked to the owner today Thanks Tom

Sweet Cheekz
05-28-2009, 02:24 PM
-------Matty,,,They made at least one with a #3 Speedmaster/427HO GT21, and they made mine with a standard #3/low HP 427. I dont think they were the only ones but I never saw any others. The Speedmaster one apparently ended up in Texas and Conquistador actually owned it, but I think DONZI took all the good stuff out before delivering it to the second owner. The first owner was a very close friend of John Chisholms. The same guy owned one of the twin Holman/Moody GT21s before the Speedmaster boat. One of the biggest problems with at least the 1st twin H/M twin boat was a single 3/8ths gas line to feed both motors if I remember correctly. I road in both boats at one time or another and both performed well but the Speedmaster boat was about a 75 or so MPH boat which trumped the twin pretty easily. That was real fast back in that period!!!!!!!!...........Bill S

Thanks for the info Bill
How did the boat handle the #3? Not interested in a twin. Curious if it can take that heavier drive Ever hear of someone putting an extention box on one?
Matty you said lighter than an early 22c? I got the impression it was heavier.
Thanks

mattyboy
05-28-2009, 02:50 PM
Thanks for the info Bill
How did the boat handle the #3? Not interested in a twin. Curious if it can take that heavier drive Ever hear of someone putting an extention box on one?
Matty you said lighter than an early 22c? I got the impression it was heavier.
Thanks



the 22 classic is a big fat pig :tongue: especially a criterion that long sleek deck fiberglass weighs more than air ;)

my records show the gt at 2900 lbs

the criterion at 3700 lbs

and the modern 22 classic at 3400 lbs

Pismo
05-28-2009, 03:28 PM
There was a tan 1978 21 GT on Lake George owned by Todd Leach. Anyone know if that boat is still around? It was in beautiful shape. 330 TRS, airhorn. He kept it in Basin Bay until the property was sold.

olredalert
05-28-2009, 04:04 PM
------Cheekz,,,I only got one ride in the single with the #3 Speedmaster so my memory wont mean much as it was not behind the wheel time, but I certainly dont remember any problems of any significance. Up until then I had never been that fast so I was sort of adjusting to that. Remember, it was 1972........Bill S

Sweet Cheekz
05-28-2009, 05:51 PM
Thanks Bill

Matty What do you show for my 16 for weight I am going to try and get mine weighed this weekend. I am positive I'm a little heavier than normal but I want to find out. Also is the deadrise the same on the gt as a 22 classic? Thanks

Parnell

Donzi Racer
05-28-2009, 05:52 PM
the 22 classic is a big fat pig :tongue: especially a criterion that long sleek deck fiberglass weighs more than air ;)

my records show the gt at 2900 lbs

the criterion at 3700 lbs

and the modern 22 classic at 3400 lbs

I would have bet the GT was heavier also. That is one reason I was struggling to understand how the orange GT could get to those speeds, but 500-800 lbs. is a lot of weight. Now what would a better prop for handling and speed compared to the 4 blade 30"? A 3 blade 32 in what name? Tom

Sweet Cheekz
05-28-2009, 05:59 PM
It just looks a lot bigger in person than a classic Struggeling to figure out where the weight has gone?

mattyboy
05-28-2009, 06:15 PM
well as i said fiberglass is heavier than air and the criterion has alot of it with the benchseat and the molded bulkheads for the front seats and the bigger deck the gt is like the 18 basically a tub in the deck

1500 lbs on an unrigged 16 will have to check if i have rigged weights for it


yes as far as i know the hornets were the only classics that had other than a 24 degree deadrise

Donzi Racer
05-28-2009, 06:18 PM
It just looks a lot bigger in person than a classic Struggeling to figure out where the weight has gone?

I agree and can you imagine a 22 classic with twin engines like a couple of the GT's had? I know they don't have the beam and the weight in the rear would be all messed up. I liked the way our 22 classic with the small block handled much much better than the big blocks in the 22's. Makes you rethink the 21 GT's. I have always loved the look of the Gentleman's Cruiser. Never thought of one running like a bat out of Hell!!! Tom

Sweet Cheekz
05-28-2009, 06:24 PM
the gt is like the 18 basically a tub in the deck


This is funny. I called my freind with a 16 after I pulled the deck off mine and told him he has a hot tub with a cover. I crawled around the inside of a 21 the other day and there is 0 support or weight forward of the dash. Thats not different than a 22c is it?

gcarter
05-28-2009, 06:44 PM
I crawled around the inside of a 21 the other day and there is 0 support or weight forward of the dash. Thats not different than a 22c is it?

No, no difference.....that's one of the problems and why the floor cracks.

mattyboy
05-28-2009, 06:53 PM
the older classics like the 21 gt and the hornet are really larger than life
the hornet is huge for a 19 foot boat as is the 21 gt they seem much bigger than a classic in their size range

the early hornets had alot of problems with the benchseat and the coring in the massive hull sides I have not had the pleasure of really going thru a gt but would love to

:yes:

Sweet Cheekz
05-28-2009, 07:06 PM
It's very cave like
I doubt it's the best with big power and no additional beefing up. If I do buy one I think I will probably do what I did to mine at least as far as structural integrity goes. Seems like bigger waves and high horsepower might be a lethal combo on this boat without some help. I saw lots of opportunities for cracking

BUIZILLA
05-28-2009, 07:28 PM
which one did you crawl around?

Sweet Cheekz
05-28-2009, 08:05 PM
Gt21

BUIZILLA
05-28-2009, 08:08 PM
uh duhhhhhhh

I guess I wasn't specific enough..LOL

Sweet Cheekz
05-28-2009, 09:03 PM
Duh Is right I just reread a few posts back and I had already said that Sorry :bonk:
It's in Michigan, unnamed, unused for the last 10 years and basically a hull and deck with a newer interior that would have to go. No dash, drive or motor Just my kind of project. Tons of structural work, glassing and hopefully a touch of creativity. We will see

olredalert
05-28-2009, 10:33 PM
------Cheekz,,,I know where there is another GT21 in Mt. Clemens area with virtually nothing but the hull and deck. Its possible it might be bought as well but it would be one hell of a project.........Bill S

BigGrizzly
05-29-2009, 07:46 AM
My Criterion tips the scales at 3800+ pounds and is built like a brick

Sweet Cheekz
05-29-2009, 08:55 AM
------Cheekz,,,I know where there is another GT21 in Mt. Clemens area with virtually nothing but the hull and deck. Its possible it might be bought as well but it would be one hell of a project.........Bill S
Bill
I would be interested in knowing more. Pics, year ect I just did one hell of a project in 6 months I am looking to take a year or two on the next one. Thanks
Parnell

olredalert
05-29-2009, 09:04 AM
------Parnell,,,I have no idea what year the old boat is, but will try to find out........Bill S

Sweet Cheekz
05-29-2009, 07:31 PM
I appreciate the effort Bill Let me know if you find anything out. Thanks
Parnell

axelkloehn
06-04-2009, 02:33 AM
...here's a pic of my GT21 which I've just bought for peanuts in Germany w/o engine and drive.
It's been delivered originally with a jetdrive...
Does anyone know which jet/engine combo it had? Delivery date must be around 1970.
Is it worth keeping the original jet if I can find one? There is a Bravo 1/454 Mark IV around in my garage, but it needs a lot of fiberglass work to get it in caused by gigantic hole in floor and Transom!!??

Cheers, Axel:germany:

BERTRAM BOY
06-04-2009, 06:51 AM
My Criterion tips the scales at 3800+ pounds and is built like a brick

Randy, did you actually weigh your boat. I've always been curious if 3800 lbs. is an accurate weight.

BUIZILLA
06-04-2009, 07:01 AM
it's pretty close...

axelkloehn
06-04-2009, 09:09 AM
Only saw a handful with jets, they were 455 Olds packages.. One was supposedly a Flagship 450hp or something according to the legend though.. Can you find a hull # anywhere on it?


...there's no hull # where it's supposed to be, even after sanding down to gelcoat couldn't find any #. After check under dashboard there's nothing marked with pen or so... must be a very early one...!?

cheers, axel :germany:

Jamesbon
06-04-2009, 09:23 AM
Right now she's only as fast as the F-150 will pull her :bonk:

...I got your number Poodle... :yes: