Tahiti boats

[jimthetoolman]

Has anybody ever had or seen a 18 foot bubble deck tahiti go faster than 65 mph. With out crazy money in the motor.. I can't seem to get past 62 with the gps. I have a 427 2 750's double pumpers with a tunnel ram and the good rectangular heads,comp cam 292. Is this thing a brick or what?

[victorfb]

i get nearly that speed with a 18' tahiti bubble deck. (actually a "runabout") and it still has the harmon marine 390 HP 455 olds, single 750 vac holley on a torker. no high dollar stuff here.
what pump are you running? mine is a berk JC. i would look more into the pump for added speed. no matter how much HP you put into a non efficient pump, you wont gain any speed. it will only work as good as it is. a properly set up pump can give you an amazing gain.
as for the hull, what i have heard is that most Tahitis were more of the river/lake boat. a bit heavier glass but stronger. they made a bunch of em.

[Jake W]

My Tahiti is a 77 bubbledeck.I have never GPS mine but will soon but think I am runn9ing 70 or so.Nothing fancie about the engine but I have a lot of pump mods.you guys have pics of your boats ?Do they look like this? http://www.***boat.com/image_center/data/521/82sidetah.jpg
[ July 18, 2003, 06:38 AM: Message edited by: Jake W ]

[Moneypitt]

How does "bubble deck" differ from the earlier Tahiti model. I've got a 69 that looks quite simular to the one shown, at least the profile. As for speed, with a 12j ab pump and a well built 402 BBC, mine was gpsed at 63 mph. Wide flat open for a mile or so, 63 mph. In an acceleration run, 63 mph when it stopped pulling. I think it would be fair to say the boat will go 63, no faster. So your speed of 65 or so is real close, and the suggestion to work the jet for more speed was probably right. A boat this heavy (mine) seems to be a good driver, takes the chop pretty well, turns on a dime, has plenty of room for the gear, and has enough speed to be fun. Trying to get more speed may be a tall order, considering these boats size and weight, and really, isn't 65 fast enough on the water? (just kidding, I know its never fast enough!!!!!)...Moneypitt

[squirt]

Along with checking your pump, get under that thing and check the bottom for hook. I have seen a number of Tahiti's that have this problem and this will really knock the snot out of your speed. What rpm are you turnning and what impeller do you have. I've seen a number of 75+ mph Tahiti's but like anyother boat it has to be set up right.
Don

[BrendellaJet]

Toolman, what RPM are you turning? What pump do you have? Impeller size? overall pump condition? Have any other cam specs? if you want my 2 cents, Im guessing your motor doesn't make enough power to turn the impeeler up to the motors peak power. Need to know the condition of the pump.

[Jake W]

the older 69 models usualy have the deep entry v and very wide I have seen some from Dick that do not though if you look at the front of mine it is not like that.I am pretty sure mine has a Rogers bottom and bubbledeck from the 18 ft Eliminator.Thers bubble decks are really a basterd chiled of several boats.Post a pic of yours.
Jake

[jimthetoolman]

Thanks for all your responces. To answer your questions. I have a Panther jet that is in good shape. The damn thing throws out one hell of a rooster tail . and the cam is a Comp Cams 292ah with 110 lope seperation and .510 lift. Also how do you post a pic on this board?

[jimthetoolman]

You also asked about rpm. Its around 5800.

[squirt]

Hey Jim, That rpm is a little high I think. One of the (local to you) guys is spinning his Tahiti with a panther around 5,200 and is seeing 68mph. I think Panthers tend to spin a little higher than the same setup with a berk style pump maybe like having a B impeller. Another guy you migh want to talk with is Cas ( he is also kinda local to you) He should be able to give you some advise on your setup. Your boat is not a brick althougt it is pretty solid. Look at the bottom for strightness but to me it sounds like your pump needs some attention
Good luck, Don

[Cas]

Jim,
Sounds to me like you at least one of three things going on. The clearance between the impeller and the housing is too big, the clearance between the impeller and stator housing is too big or the stator rings are worn or non existant. That's all assuming there's nothing lodged in the impeller or stator blades.
First thing to do is to crawl under the boat , look up into the intake to make sure it's all clean in there.
Next thing is to remove the stator housing and all the linkage from the main housing, 4 bolts on hold it to the main housing. Take a close look at the main housing where the impeller meets the housing to see if there is gouging in the housing. If there is, you need to pull the impeller so all the gouges can be fixed.
Now focus on the stator housing.
http://www.***boat.com/image_center/data/500/210stathous-med.jpg
The stator rings will be on the area that fit into the impeller. There should be 2 of them and they should be about 1/8 in height.
http://www.***boat.com/image_center/data/500/210statrings1-med.jpg
You can see the stator rings in the above pick.
The third thing which should actually be number 2 is to check the clearance between the impeller and the stator housing. The is checked by placing a straight edge across the main housing and measuring the clearance between the straight edge and the impeller.
If you want some help, I'll be more than happy to give you a hand. The tough part is when?

[Cas]

btw, as far as Tahiti hulls go, more than likely you have about 1/4" hook on the bottom. That will need to be removed in order for the boat to reach it's potential.

[jimthetoolman]

I have used dev-con puddy to remove the grooves. But I still have a somewhat deep groove at the front of the impeller. I still have wear rings on the stator housing.. And Yes I would like that if you could check it out how about tommorrow? I will be waiting out in front of my house around 11:00 am. Just kidding. Thanks for all of your help so far.

[Cas]

Jim,
You just might luck out, I'll be in Walnut Grove this morning. I got your number off the LBBA message boards so I'll give you a call on my way over there. I sure hope you'll be awake when I call :D
it'll be about 9am or so.
I'm giving squirt a hand taking down a portable carport thingie. If you can make it down around 11:30 or so, I'll be more than happy to check it out for you.

[jimthetoolman]

yea I will be up. Be glad to hear from you. Thanks

[Moomawnster]

Cas , why do you assume the boat has hook , and why is that bad .... where do you measure for it ? and how does it get there ? my boat only rides on the last 3ft or so of the hull ..... Moo

[1Bahnerjet]

Well you know back in the '70s Tahiti's goal was to Build as many Boats as fast as they could. Later on they started to look at the Quality of there Boats, Maybe to Late?
http://www.***boat.com/image_center/data/500/43e-med.jpg
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Thats BANNER with an H

[Taylor LP]

jimthetoolman:
You also asked about rpm. Its around 5800. Might want to check that tach, too!

[Cas]

Moomawnster:
Cas , why do you assume the boat has hook , and why is that bad .... where do you measure for it ? and how does it get there ? my boat only rides on the last 3ft or so of the hull ..... Moo Moo,
I've had 4 Tahiti's and they all had about the exact same amount of hook. I think it's built into the hulls. Hook can also happen over a period of time with the boat sitting on a trailer that the bunks are too short.
To check for it, take about a 4 ft straight edge and place it on the bottom of the boat from the transom forward. I usually check it at 3 different spots on each side. If there's a gap between the straight edge and the bottom of the boat, it has hook.
Hook in the bottom of the boat can and will force the bow down, especially at higher speeds. Doing so gives the boat more wetted surface which will prevent the boat from reaching it's potential.

[old rigger]

1Bahnerjet:
Well you know back in the '70s Tahiti's goal was to Build as many Boats as fast as they could. Later on they started to look at the Quality of there Boats, Maybe to Late?
http://www.***boat.com/image_center/data/500/43e-med.jpg
--------------
Thats BANNER with an H The quality was there in the 60s when they were introduced. A early Tahiti is built as well or better than most boats from the same time. Dick Schuster was first a laminator before he struck out on his own, building boats for the legendary PowerCat boats from the late 50s and early 60s. I've owned handful of 60's Tahiti's that were old when I got them and none of them had any hook. All the bottoms at the keel were an inch thick. Hook was never built into any Tahiti, that came from pulling the parts from the molds too fast. That and installng the intake quickly and the boat not fitted to the bunks on the trailer properly all added to te hook in the bottom.
You'll get no argument from me about them building lots and lots of boats, but most of the bigger shops did in the 70s, it was a golden time, everyone had cash and gas was cheap. By the late 60s Bell owned Tahiti and they, like Eliminator and countless others were pumping out boats at a mind boggeling rate.
Bahner was also famous for staring out with a good product, built a loyal following by racing (with a Rogers bottom) but towards the end of his run, his stuff really slipped in quality. And I don't mean a little bit. We repaired more of his boats that I can't even count over at Advantage in the late 80's. He was good friends with the owner there and they had a deal worked out for fixing his stuff. Mainly because Bahner was in hiding.

[1Bahnerjet]

OldRigger, Yeah I heard the Bahner Story, he made a good boat, you just wouldn't want Rod to do your Taxes. :rolleyes:
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Thats BANNER with an H

[Moomawnster]

Thanks for the mini lesson Cas , now if the boat has rocker ... is that good ? I haven't looked yet but my boat airs out pretty well , I do realize that a small amount has a huge effect ..
OK OK ! I'll get out a straight edge! :rolleyes:

[jimthetoolman]

Cas: I did what you told me to do on the phone yesterday (To check the clearences) and you where right! my clearences where off on my impeller. But why would this make my rpm so high?. This is a stupid question I know but Work with me I am a mildly retarded. Just mildly.

[Cas]

OR,
Thanks for the clarification about hook not being built in but may have occured from pulling the molds too fast.
Moo,
I don't have any experience with rocker at but I'd think it would make the boat feel real loose. I guess it would be like trying to balance yourself on a big beach ball. :D

[old rigger]

1Bahnerjet:
OldRigger, Yeah I heard the Bahner Story, he made a good boat, you just wouldn't want Rod to do your Taxes. :rolleyes:
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Thats BANNER with an H ???????
His being in hiding had nothing to do with the way he handled money.
but you're right, for a while he made a good boat.
[ July 20, 2003, 11:37 AM: Message edited by: old rigger ]

[squirt]

[
but you're right, for a while he made a good boat. [/QB][/QUOTE]
Yeah I'm with ya on this Old Rigger. The only thing is most people only remember the bad parts about Rod and his boats so most people think his boats were $hitty. The only bright side to it is you can get some good deals on his boats cause of the bad rep.
Don :D