Post Your Classic's Top Speed

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CSR member and hydroplane driver Steve David's ride does laps at just below 160mph on the Columbia River. On the straightaways it's probably pulling around 185. Not bad for an old guy with a funky looking boat!

Just kidding Steve. Nice job in the Tri Cities and in Seattle!
 
My engine can do 70 mph.....

of course thats when it's in the back of a pickup truck being taken to the machine shop :)
 
Still working on this.

1987 Seville II Mid-Cabin 21'
Dry weight: 3,300 lbs
Fuel: 48 gallons (est 290 lbs?)
Water: about 10 gallons-ish?
205 HP V-6 (4.3L 4-BBL)
Alpha 1 Drive
Old prop: 15x17 3-blade
New Prop: 15x16 4-blade aluminum (Merc Alpha-4 prop)

With Old Prop on the dash speedo (suspect inaccurate):
Cruise: 18-20 @ 3300 revs
Took it to WOT for a little bit once: Dash speedo only read 25, so I doubt it is accurate. This thing should be well over 30, considering the small size.

I have a GPS unit from another boat, and an antenna. Also have an Alpha-4 Merc aluminum prop (all brandy-new). Haven't taken it out with the GPS or the new 4-blade yet.

Will post results when I can. Boat is new to me, and I've only had it out twice. This boat is my 6th, and I find myself liking this one more than most of the other, bigger, predecessors.
 
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56 on speedo with a freshly cupped mirage plus 3 blade stainless prop. 1/2 tank of gas by myself in a slite chop.
 
Newman said:
1986 Seville 190 Mercruiser (3.7? Still learning) Not sure what speed is at WOT but I ran it up to about 52-54 before I backed off last summer. 3 people and 1/2 tank of gas. I was happy.
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After reading all the posts I think I need to not believe the needle on the my speedo. Maybe closer to 44 mph? I dunno. Another thing to note is I have a 170, not a 190. Although the PO said he had the head ported and polished with higher comp pistions. All I know is it runs like a scalded dog.
 
Seville 160 BROB 100HP ~45MPH (over-propped by previous owner with a 13-1/4-inch diameter/19 pitch SS Turning Point Express)

Jake
 
I finally get to post in this thread for the 268 t4.3 205hp OMC cobra. 70 gallons of fuel, 25 gallons of water, about 350 pounds of human meat, a couple coolers full of food and drinks and a metric ton of unncessary crap that the wife deems must have on a couple hour boat ride. 14.5x19 props, no tabs, drives trimmed up, WOT, port eng 4,100 rpm, starboard 4300, smooth water for a grand total of 42 mph on the gps. I'm a little dissapointed as I was hoping to closer to 50 but 42 isn't bad for her size I guess. What effect would throwing my spare props on have? They are 15x17.
 
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JAB said:
I finally get to post in this thread for the 268 t4.3 205hp OMC cobra. 70 gallons of fuel, 25 gallons of water, about 350 pounds of human meat, a couple coolers full of food and drinks and a metric ton of unncessary crap that the wife deems must have on a couple hour boat ride. 14.5x19 props, no tabs, drives trimmed up, WOT, port eng 4,100 rpm, starboard 4300, smooth water for a grand total of 42 mph on the gps. I'm a little dissapointed as I was hoping to closer to 50 but 42 isn't bad for her size I guess. What effect would throwing my spare props on have? They are 15x17.
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Well, fisrt off, your engines are not synchronizing. I've had that issue before with a previous boat. Turns out that the backfire flame suppressor had "just enough" bent fins on it to limit airflow. Make sure those are straight and clean, too.

Next, going from 14.5x19 to 15x17 would result in your engines picking up about 200 rpm. A half inch of diameter is equal to 1" of pitch. COnsidering that:
14.5 x 19 is equal to 15 x 18.
You want to put on your 15 x 17, so that be a shallower pitch, resulting in an increase of about 200 rpms (give or take). That'd put your engine in the design rpm WOT range (4400-4800), versus overpropped as it is now.
 
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Miss Elli said:
My 78' 260 Sundancer with twin 165's beginning of season with new teflon antiflouling 41 mph. My old Lady
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What props are you running? Your boat seems similar size to mine with a little smaller engines and were running about the same speed.
 
At cruising speeds i have to back off the throttle lever on one engine to sinc them so im hoping its a cable issue just not pulling the throttle open quite enough on the other engine, i have plans to replace all the cables and a major tune up this winter.

Am I right assuming with the 15x17s it won't plane out as quick but will pick up some top end mph? That kinda makes sense, as it is now it jumps up and planes and hits top end within a few seconds with no tabs.

Also would it be worth it to set up a counter rotating setup on one side? What would it take to do? Rixram has a Lefty prop for sale but I'm not sure if its worth the effort to change over.

Rixram said:
Well, fisrt off, your engines are not synchronizing. I've had that issue before with a previous boat. Turns out that the backfire flame suppressor had "just enough" bent fins on it to limit airflow. Make sure those are straight and clean, too.

Next, going from 14.5x19 to 15x17 would result in your engines picking up about 200 rpm. A half inch of diameter is equal to 1" of pitch. COnsidering that:
14.5 x 19 is equal to 15 x 18.
You want to put on your 15 x 17, so that be a shallower pitch, resulting in an increase of about 200 rpms (give or take). That'd put your engine in the design rpm WOT range (4400-4800), versus overpropped as it is now.
Click to expand...
 
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JAB said:
At cruising speeds i have to back off the throttle lever on one engine to sinc them so im hoping its a cable issue just not pulling the throttle open quite enough on the other engine, i have plans to replace all the cables and a major tune up this winter.

Am I right assuming with the 15x17s it won't plane out as quick but will pick up some top end mph? That kinda makes sense, as it is now it jumps up and planes and hits top end within a few seconds with no tabs.

Also would it be worth it to set up a counter rotating setup on one side? What would it take to do? Rixram has a Lefty prop for sale but I'm not sure if its worth the effort to change over.
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If you have twin engines, one prop is left handed and one is right handed. They spin in opposing directions to counteract sternwalk. If both engines spun the props in the same direction, there would be some slow speed handling issues.
 
It does seem to wander quite a bit idling around. Both props are marked and look identical, 14½X19 391201 and the spares are marked 15x17 391200.

Is it possible someone changed it? Would there be a benefit to not having counter rotation one one side? The boat was only used 1 season since it was new so maybe they were having problems and thats why they parked it.
 
how does 25.9 knots gps speed with 4 adults 100 gal water 300 gallons fuel a 30 pack coors light and a bottle of vodka
 
JAB said:
It does seem to wander quite a bit idling around. Both props are marked and look identical, 14½X19 391201 and the spares are marked 15x17 391200.

Is it possible someone changed it? Would there be a benefit to not having counter rotation one one side? The boat was only used 1 season since it was new so maybe they were having problems and thats why they parked it.
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If possible, take a close look at your props. See if the blade rake goes in the same direction. If they do both go the same direction, at idle speeds (in gear), the boat would drive consistently to port.

AFAIK, there is absolutely no advantage to running props spinning the same direction, unless you *really* like turning to port. Opposing rotation results in a relatively straight track; note that an amount of "wander" (drift right, then drift left, on own) is typical.
 
Stopped by my shop and looked at the drives today, there identcle. the little adjustable fin on each drive is adjusted clockwise on each drive to the number 3, I assume this takes care of driving to one side?

Rixram said:
If possible, take a close look at your props. See if the blade rake goes in the same direction. If they do both go the same direction, at idle speeds (in gear), the boat would drive consistently to port.

AFAIK, there is absolutely no advantage to running props spinning the same direction, unless you *really* like turning to port. Opposing rotation results in a relatively straight track; note that an amount of "wander" (drift right, then drift left, on own) is typical.
Click to expand...
 
JAB said:
Stopped by my shop and looked at the drives today, there identcle. the little adjustable fin on each drive is adjusted clockwise on each drive to the number 3, I assume this takes care of driving to one side?
Click to expand...

Well, if you are not having any issues with tracking straight, then I guess so!
 
1990 390, twin 454 1/4 tank of fuel, no water, pretty lite 32.1 on gps. still have tune work to do
 
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