Straight Bottom T/G Speeds
 

Post up your Power/drive/speed combos for your straight bottom gun.

Full cabin or cover girl cabin.

how is Bill Procter's spider boat doing these days. Is it still the fastest straight bottom?

Straight Bottom T/G Speeds
 

My 1997 T/G with full cabin, pump out head, 5 adults, 2 grandsons, a pile of Italian sandwiches, a cooler full of ice and drinks, and 3/4s fuel load ran 73mph on GPS couple of weeks back. Powered by 525s/c's, spinning 26p 4 blades on Bravo drives at 5,000 rpm in brackish water.

Whatcha up to??? This will b a fun thread to re-spark after many years.....:food-smiley-007:

Will be interesting to see who is actually running/using theirs and not in moth-balls. Looking forward to see if anyone inputs on the Spider boat. I'm still running Old School, now with fresh Wesco power...1200's on Sixes turning to 6100rpm...can hit 100mph at 54-5500.....just haven't stretched her out yet...seem to always have to take the wife n kid:daz:

97 kevlar 1/2 cabin w/ 600sc w/bravos ran 80ish
2000 straight bottom/full cabin 500efi's w/ bravos ran 72-74ish
2000 TS 1/2 cabin w/ 600sc's runs 90ish

That boat is up for sale - I think I saw it here in our classified section. (The spider boat)

I have a few of questions for you if you don;t mind.
1. What Cubic inch and blower?
2. What fuel are you running @ 1200hp?
3. What props are you hitting 100mph @ 5500 RPM?

We have similar boats, you have more HP, just curious if I do turn up the power in my boat.

598's with M4 procharged...built and set up by Dave at Wesco. They are mildly set up at 1200hp with room for more but not needed and generally they don't feel much different than running the N/A 750's previously in the boat...Nice to be able to change pulleys/boost set up. I run pump fuel with Boostane. Props are four blade, usually 33's or 34's depending on the day, but still dialing in. Had a porpoise issue at mid-90's where it wanted to hop into the clouds unless I drag some tab...wicked/not good....with anything less than a half tank of fuel, it goes away and is on rails...over half tank of fuel throws balance off too far for those higher speeds even with #6's on it.

What are you running in your set up?

[QUOTE=38Raptor;4481392]598's with M4 procharged...built and set up by Dave at Wesco. They are mildly set up at 1200hp with room for more but not needed and generally they don't feel much different than running the N/A 750's previously in the boat...Nice to be able to change pulleys/boost set up. I run pump fuel with Boostane. Props are four blade, usually 33's or 34's depending on the day, but still dialing in. Had a porpoise issue at mid


What gear ratio do the drives have?

Running 572 Cu in with 14-71s, 1000hp. and SSM 5s on boxes. I have bad porpoising also, but not at speeds over 65-70. Honestly, not much seat time at speeds over 90mph.

I have a set of 30s on there now, have not been much over 5000rpm at all, setup to run right at 6000rpm. I think my drive ratio is under 1.5, more like @ 1.4+. Have seen 92mph at 5100-5200rpm with the 30s. I have a set of 32s to try which run a lot better.

I ask about your setup because I would like to set them up to run 1100-1150hp a side, and with the correct props 32,33, or 34p 4 blades, in hopes that 100+mph is easily touchable at that setting. I do run 93 non-ethanol w/ Boostane, probably around 99-100octane in tanks. I only got 15 hrs this season, so setup is not ideal at this point.

That's a really nice set up - I couldn't go with the 14-71's and fit under my motor hatch...have an 04 style hatch and wanted to keep it. Have zero blower surge with pro-charger set up....think that's why they "feel" so tame. Have 1.62 gears in #6's turning in. With 1100hp, you will be able to break into triple digits....just be aware of that fuel/balance issue once you start rolling into the mid-90's...night/day difference...it's more like an even worse "hop" than a porpoise...very similar to your Avatar...not a good feeling at those speeds!!!

I believe when Craig had this one, he posted here w/pic that the best he saw was 112mph w/1240 Sonny Lenoard quad whipples in it. He had a set of 16-1/2 x 33's if memory is right...the boat does like smaller diameter...17 is too much. I have pretty much the same HP but way more torque in this set up

16-1/2", really? Drives even with bottom? I had trouble getting on plane with 17-1/2" x 32s. I currently run 17-1/2" x 30p and it still struggles getting on plane with full fuel.

I can see that on the top end, it would like the 16-1/2", but hard to believe your boat runs well with the smaller diameter. I am going to get the 32s worked on, bump the pulley down a little for next year, and see if I can get there without too much more $$$.....

The prochargers are definitely cool, and sound wicked spinning that fast. I don;t want to screw with the boat too much, I really just want to go boating. Also, a little timid on blowing up #5s, they do have their limit, and I prefer not to know what that is...

92. Carbon fiber top gun bought in01 with 502 Eli's 62 mph repowered 05 with 600 mercs xz's 87 mph out of fuel no passengers repowered 09 1000 mercs dry sump sixes 101mph turning 17.5 X 34 4 blades

about the porpoise problem I owned a 97 tg half cabin Kevlar called big kahuna it had 600scs from factory rebuit to 750hp with bravos 380 k planes had to run tabs to # 6 to stop porpoise hated the boat .put 5 blade hydromotive props spinning in or out no more porpoise hope that helps

I'd say thats pretty dialed in. Turning 33's to 5400 and 100MPH with 1.62 drives, thats 4% slip. On an old straight bottom top gun , thats amazing slip. Most cats can't even get that.

That boostane is interesting stuff. What octane level do you shoot for, and how much boost you running? Seems like an affordable option to race fuel

650 hp 540s #3 drives 1:40 gear ratio running 26p 3 blade 16.25 diameter props. saw 81.4 on gps at 5300rpm in perfect conditions but it will run 76-77 every day. My boat hates larger diameter props too porpoises worst the larger diameter I run. And by perfect conditions I don't mean under the peace bridge going with the river current I think I could hit high 80s there lol

I wish.....More like 9%....34's at 54-5500 at 100...with the 33's at 5400-ish it loses a bit down to 95/96. Boat has allot left in it but Season is about over up here so will get the 34's to 6200 next summer when I grow some bigger Kahunas for more trim over the winter:evilb:

I won't run my motors without Boostane....not worth the risk. Not really for the octane boost for me, it's more about the fuel treatment. I run one quart per 100 gallons on 93 pump gas, on harder run days I'll run two quarts per 100 for a little piece of mind. Had a buddy blow up his fresh motors early this summer from local marina gas and forgot to add it in...have seen this movie, and lived it WAY too many times. It's shocking how many catastrophic motor problems come from crap gas...marina or station. Super cheap insurance IMO

Saw you headed into Sutton Bay two Saturdays ago. Looked and sounded great. One of the better 90's paint jobs.

When it comes to planing, my boat doesn`t care about diameter or how many blades. It`s all about the cup. 18" 5 blades and little cup= 5000rpm burnout for 5 minutes.


Now this thread is all about "my boat hates large diameter props" when the last one was all about large diameter to stop the porpoise. **** this I`m getting a Fountain those bastards run straight as an arrow.:evilb:

^^^Too funny Dan.

There is some good info here though, please keep sharing, because it might save one of us thousands of $$$ in setups, props, etc.

I also run Boostane for the safety factor, similar mixes to Raptor above, cheap insurance I guess. I am not a Chemical Engineer, however, seems like the stuff works. If I could get a season together, and figure out this setup, would be a happy man.

Seems like 1000hp, surface drives, and the right props all boats pretty even @ 100-103mph. How much does it take to get to 110? 1200hp?

In all honesty, all the hype I've read about these boats, I'm not exactley blown away by the handling in big water at faster speeds. You'd would think these things drive themselves through 6ft waves without having to "drive" the boat. Not what I have found to be true.

That's just my Nashville high-test Power Wheelie!

Someone I know had a nice idea to lengthen the front inner lifting strakes . On the Fountains they extend much further down the boat.
You can see the water leaves the front strakes and the bow falls only to be lifted again. This also may be the hop 39Raptor was referring to.. feels more like a hop then porpoise to me anyway.


https://www.youtube.com/watch?v=DkFZo9x-vWg&feature=youtu.be

(Now that all my engine stuff is all taken care of I`m moving on to handling)

How fast were you going there? 65mph?

Be nice if we could solve this one, once and for all. I hate the "hop"

MPH was Mid 80`s I think.

I ran a Kevlar gun this weekend with bravos and 600sc's. Hop or porpoise was worse than any other gun I've been on. Drives are real high, this was an early lip ship boat. Going to put a 1" spacer in and lab the props see how it is. Could extend the strakes a little further and engineer some rocker into them to hold the bow down a little

our top gun has some hop but can often be corrected with tabs and drive height. in the video I bet if you tucked in the drives it would eliminate a lot of what you see. granted it's not conducive to going fast.

Is this just a result of taking what was designed to be a 75mph boat back in the day and trying to run them over 90mph? Did the 90mph guns have a modified or tweaked bottom in order to offset this negative ride attribute? Would be nice if one of the "90" owners chimed in on this. (They were staggered, that would affect the balance).

"Locked and Loaded"???

They're not built to run on rivers and small lakes. Get those boats in any chop and porpoise will be gone

They were first built as race boats that went 90 and later became pleasure boats.

Every Cigarette Ive owned porpoised at cruising speed, especially in flat water..Old School was definitely a different animal with the 6's.
Now I have a 35 Fountain(flat bottom), and it does the same thing. I usually bump the tabs down til it stops and then gradually bring them up. OR if I speed up, the porpoise will stop that way too.
With a 1-2 ft chop,they all ride much better...... Ive also notice, that the Fountain gives a "flater" ride than the Cigarette when going high speeds.Flat bottom Cigarettes always seemed to ride "bow up".
I am a river rat, so the flat fresh water really isnt what these boats were built for.

I will admit, that when the Sandusky bay was kicking up a constant, and predictable, 2-3 ft wave set, it's the best the boat has ever run. Smooth as heck @ 75mph.

My one bad experience has me a little spooked so I was probably laying off the throttles and had the boat setup wrong for cruising. She runs great above 90 with 1-2ft chop, straight, solid, and predictable.

Bravo Straight bottoms changed the Center of Gravity, they hopped more. I rode on a 1/2 cabin 87 bravo Top Gun, it was bad. Guns were built to have transmissions and better weight ratios.

I think straight hulls all have a lil porpoise in them, just comes with nature of the hull. If it's dead smooth mine will not at cruise 48-52mph, gets just a lil chop it will start & never stop. Lil negative tab it goes away. Anything above 60mph the nose lays over & goes over near anything.

I've run several bravo top guns, this one acts very differently. It is the only Kevlar, bravo gun I've ran though

Mine runs straight as an arrow from 70mph and up. No hop. Drive input no longer does anything for speed so I run them level and tabs are all the way up at 70mph plus.

I've gotten myself in trouble running fast, in bigger water, above 70mph with the tabs all the way up. Never again. they will always be even with the hull or slightly negative from now on. Boat is extremely bow happy, might be the tonnage I have bolted to the rear end.

These things do not fly level. Would look into getting into a twin step or catamaran after this boat.

I have been on a handful of 38 cigs. Things change when you get away from the TRS / Bravo props and get into the ssm stuff handling wise.

Anyway to find COG on these without an Engineering study? Does anyone know where the designed COG is?

idea - I could just hang it by one of my cranes by one strap and figure out which way it tips, then mark it.....

What I have found is that all older boats need double the HP they were built with so that they can cruise at the original top speed. They all seem to get happier at 65+.

My little 27 is the same way, Most comfortable at 60+, other wise it feels like its apart of the water vs running over the top.

Craig's "Hero" shot from a few years ago on Old School.....check out drives/tab position. I haven't topped his 112# yet but have the pony capability to do so and want some new pics.[ATTACH=CONFIG]559682[/ATTACH]


Frick - agree with you, you have to keep tabs in play at higher speeds in certain conditions. I have a full cabin w/enclosed head....amazing how removing Every pound of extra "crap" up in the nose and under a half tank of fuel makes for a much flatter smooth ride. You need to come up north next summer to play!