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Discussion Starter · #1 ·
can someone explain what a runner bottom does for the boat,i have an old true flat but always see runner bottom,s on this site.
 

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Think of a true flat...you get on the gas and the boat needs 3 hops to get the air our from under it...big flat surface up and down in the air...you have to displace the air...hence..hop hop

Now you have a runner bottom...air goes out the back..It dispels air quickly and sets the boat faster...
 

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To me, the two styles have a completely different feel, especially driving them. A true flat feels glued in, like stuck to the water. Where as a runner bottom feels lighter and kinda loose, even at cruising speeds. Which is best? As always, depends on what you want to do. If you want to go as fast/quick as possible with whatever HP you have, a properly set up runner will always cover a true flat. If you're a lake/delta runner that wants something cool but the last 10-15 MPH of top speed isn't that important, IMHO, a true flat might be a better choice.
 

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Discussion Starter · #5 ·
To me, the two styles have a completely different feel, especially driving them. A true flat feels glued in, like stuck to the water. Where as a runner bottom feels lighter and kinda loose, even at cruising speeds. Which is best? As always, depends on what you want to do. If you want to go as fast/quick as possible with whatever HP you have, a properly set up runner will always cover a true flat. If you're a lake/delta runner that wants something cool but the last 10-15 MPH of top speed isn't that important, IMHO, a true flat might be a better choice.
so what speed difference would be expected in the 425 hp range.
 

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It's difficult to make good comparisons between a true flat and a runner bottom. True flats tended to be older and heavier than runner bottoms. My Stevens which was a 1970 true flat that weighed 760 lb while my Cole Runner bottom weighs about 575 lb. Both are pretty standard medium weight boats of their time. The Stevens ran about 85 with a 427 BBC, while the Cole is considerably faster.

The runner bottom is considerably narrower than the Stevens, but the Stevens had more room. The Stevens would turn much better than the runner bottom, so in that regard it was more fun. I can't compare performance as the two boats were powered much different.

When talking about true flats, there are the older true flats and there are also the Circle flats of today, and they are quite different from each other.

Rather than get into something that I don't really know, you might want to check out an old posting where they are discussed.

[url]http://www.performanceboats.com/v-drives/52562-true-flatty-v-s-runner-bottom.html
[/URL]
 

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so what speed difference would be expected in the 425 hp range.
Though I'm sure people have done it, I've never owned or worked on a runner bottom with much less than about 650 HP so I can't really help with an answer. I have been in a few vintage true flats with around that HP and they were a lot of fun but no speed demon.... think in the 50-65 MPH range. Any true flat I've tried to go fast in was some kind of circle boat and 650 HP would get you in the 100-110 MPH range with some work.....
If I were to make a suggestion, don't get to hung up on top speed. A lot of these 60 MPH vintage flats are cool AF. Pick something that speaks to you, put your ass in the seat and run it while you learn what you like. My tastes in flats has evolved a lot in the 30+ years I've been messing with them and if I had more space, I'd have probably have 10 of them because each style is so cool in it's own right... Good luck!!
 

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Discussion Starter · #8 ·
i bought the boat [76 hondo t deck true flat] about 10 years ago for two reasons,reason one-i liked it,reason 2-it was pretty much the same color as a 80 sanger runner bottom i had,i put a blown 454 in it and sold it after using it one time.a guy saw it where i had it stored and asked me if it was for sale,i said 20k would buy it,a week later he bought it and i never heard anything about it after that.i wish i still had that boat.
 

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i bought the boat [76 hondo t deck true flat] about 10 years ago for two reasons,reason one-i liked it,reason 2-it was pretty much the same color as a 80 sanger runner bottom i had,i put a blown 454 in it and sold it after using it one time.a guy saw it where i had it stored and asked me if it was for sale,i said 20k would buy it,a week later he bought it and i never heard anything about it after that.i wish i still had that boat.
Are there strakes on the bottom of the boat? If it has them then it is considered a circle boat as that was what is was designed for. That would be a holdo "sprint". Very cool boats and run and handle very well. Also a little more efficient of a design than a regular true flat.

Paul
 

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Best Explanation I've Ever Heard!

Think of a true flat...you get on the gas and the boat needs 3 hops to get the air our from under it...big flat surface up and down in the air...you have to displace the air...hence..hop hop

Now you have a runner bottom...air goes out the back..It dispels air quickly and sets the boat faster...
Wow! That was impressive.
 

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I own a Hondo runner bottom. I love the handling except when I want to make a tight turn. IMO, flats have that aspect sewed up.
Although this is a picture of a previous owner and different engine, this is the boat I own. Pure badness.



 

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I own a Hondo runner bottom. I love the handling except when I want to make a tight turn. IMO, flats have that aspect sewed up.
Although this is a picture of a previous owner and different engine, this is the boat I own. Pure badness.

Nice looking boat.

I think most who have a runnerbottom will agree they handle very well, except when turning at slow speed. There's been more than once that I've started a left turn, only to decide it wasn't turning fast enough and ended up turning right to complete the turn.
When I had a true flat, it may have turned better one way than the other, but it turned either way reasonably well at slow speeds.
 

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Nice looking boat.

I think most who have a runnerbottom will agree they handle very well, except when turning at slow speed. There's been more than once that I've started a left turn, only to decide it wasn't turning fast enough and ended up turning right to complete the turn.
When I had a true flat, it may have turned better one way than the other, but it turned either way reasonably well at slow speeds.
Most drag race runners have the small drag fin like in the pic and most have shortened the rudder from 12" down to 9-10". Both have a big negative effect on low speed handling. Runner bottoms with full length rudders and a decent turn fin handle pretty well...
 

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My Cole TR-2 has the above mentioned drag fin and a full size wedge rudder. While this is the only runner bottom I have ever driven, I feel mine turns fine. 519 and his son Ryan have both driven my Cole, and commented on how well they thought my boat turned.
 

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Most drag race runners have the small drag fin like in the pic and most have shortened the rudder from 12" down to 9-10". Both have a big negative effect on low speed handling. Runner bottoms with full length rudders and a decent turn fin handle pretty well...
Also the design of rudder makes a difference. Great points David. Also the placement of the turn fins forward or aft make a difference.

Paul
 

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As for this boat. I spoke to the previous owner and he seems to remember trimming the fin and rudder on it. I do know its heavy.

I own a Hondo runner bottom. I love the handling except when I want to make a tight turn. IMO, flats have that aspect sewed up.
Although this is a picture of a previous owner and different engine, this is the boat I own. Pure badness.



 

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Most drag race runners have the small drag fin like in the pic and most have shortened the rudder from 12" down to 9-10". Both have a big negative effect on low speed handling. Runner bottoms with full length rudders and a decent turn fin handle pretty well...

I wasn't thinking about that, and I think you make some good points. My TR-4 had been a pro gas boat and does have a shortened rudder and a drag fin. My first flat was a Stevens with a standard rudder and two large turn fins.
 
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