Need help from Ron Hill!!

**Ron Hill** · 08-16-2013

My dad had a Rocholt Runabout, and he played with bottoms at his cottage at Lake Elsinore. By the time I was old enough to walk, I was told flat bottoms, sharp trailing corners were very important. Earl Bentz wrote a book about Performance improvements, it could have been written by my dad.

This aluminum boat's bottom actually caused me to have a "Nightmare" last night!

**omcstratos** · 08-16-2013

Originally Posted by Ron Hill

This aluminum boat's bottom actually caused me to have a "Nightmare" last night!

Its not that bad is it!?

**Master Oil Racing Team** · 08-16-2013

I got to thinking about my advice, and thought....that is probably the hole to drain the boat. And I said to epoxy it up and hammer the ends closed. I was thinking of higher speeds for the boat and not the drainage. There seems to be maybe a drainage hole to the starboard, but it's hard to tell. I noticed though in the pictures that there had been a lot of extra riveting in the bottom ahead of the transom. If the V is not needed, then I would suggest as I did before, fill it in and hammer it shut.

**Gene East** · 08-17-2013

Originally Posted by omcstratos

Its not that bad is it!?

Perhaps not for a john boat intended for fishing, but for a racing application, YES IT IS!

Your straightedge clearly shows a hook of about .100 inch. When I was actively involved, Pro-division racers strived for totally FLAT (.000 to.010 inch hook or rocker) with sharp edges at the transom.
BTW: A highly polished finish did NOT seem to be an advantage as long as the sanding was done fore and aft. Never cross ways!

We achieved this flat bottom when I was racing by hand sanding with a glass foam insulation block commonly called a "stink block" because of the sulfur smell emitted while sanding with them. I was too hard headed to wear gloves while sanding so during the racing season, I never had fingerprints. Probably would have made more money cracking safes than racing boats.

In addition, it was not uncommon to haul flat bottom boats upside down or on the side.

Achieving a totally flat bottom on a welded and riveted boat is nearly impossible.

I agree with Wayne on reshaping the hollow runner down the middle of the bottom and since it is my understanding that you are a drag racer and turning probably isn't a big deal, you may want to consider shortening the length of this runner just a bit to allow the water to re-merge even earlier. However, bear in mind this runner also stiffens the bottom and you already have a hook.

If you do trim the runner back, DON'T GET CARRIED AWAY!

Good luck!

**Ron Hill** · 08-18-2013

Originally Posted by Gene East

Perhaps not for a john boat intended for fishing, but for a racing application, YES IT IS!

Your straightedge clearly shows a hook of about .100 inch. When I was actively involved, Pro-division racers strived for totally FLAT (.000 to.010 inch hook or rocker) with sharp edges at the transom.
BTW: A highly polished finish did NOT seem to be an advantage as long as the sanding was done fore and aft. Never cross ways!

We achieved this flat bottom when I was racing by hand sanding with a glass foam insulation block commonly called a "stink block" because of the sulfur smell emitted while sanding with them. I was too hard headed to wear gloves while sanding so during the racing season, I never had fingerprints. Probably would have made more money cracking safes than racing boats.

In addition, it was not uncommon to haul flat bottom boats upside down or on the side.

Achieving a totally flat bottom on a welded and riveted boat is nearly impossible.

I agree with Wayne on reshaping the hollow runner down the middle of the bottom and since it is my understanding that you are a drag racer and turning probably isn't a big deal, you may want to consider shortening the length of this runner just a bit to allow the water to re-merge even earlier. However, bear in mind this runner also stiffens the bottom and you already have a hook.

If you do trim the runner back, DON'T GET CARRIED AWAY!

Good luck!

If you search for John Peeters on Facebook, you'll see how a six straight Nationals Champion is OSY 400 flattens a bottom.

John's mother is my cousin.....His dad learned bottom flattening years ago!

My dad would keep my boat upside down, within 30 minutes of race time, and hit it with a "Stink Block" just before the race. As we found, coming from California where the are is dry, racing in humid climates caused our transoms to swell, and a 1/16 cold and would cost you a Nationals.

.125 inch lip (hook) in the last 1/8 of the bottom, will keep a boat from planing. I once told a guy how t glass his bottom with masking tape. He pulled the tape without sanding the bottom, the "LIP" where to masking tape was, kept the boat from planing,

**Fastjeff57** · 08-19-2013

...".125 inch lip (hook) in the last 1/8 of the bottom, will keep a boat from planing. I once told a guy how t glass his bottom with masking tape. He pulled the tape without sanding the bottom, the "LIP" where to masking tape was, kept the boat from planing, "

Due to prop cavitation?

Jeff

**omcstratos** · 08-24-2013

I have a little improvement from my last prop test. I finally broke through into the 40s. The 12.5 x 22 with the extra inch of diameter seems to really respond better. Holeshot has dramatically improved and so has "grip" in the water. The previous prop felt like it had excessive slip.

Max rpms are 4800, 2.42 gear ratio, 22in pitch, and 40 mph. This calculates to 3.2% slip according to the calculator Zul8tr uses. Hard to believe it is that low. I think maybe a 20" might work better maybe?? I'd like to run 5500 to 6000 not to lug it.

It is just a fishing/hunting boat so I will be happy if max speed is in the mid 40's. (much better improvement than 28mph with the original 13pitch aluminum when It was first given to me)
Oh, I also raised the motor up a lot higher with the better grip. Found my max height before water press drops off.

Next step,,, flatten out the bottom with the epoxy and try out a 12.5 x 20 I suppose..

**Ron Hill** · 08-24-2013

I don't have any 20's, right now....but I probably should make some. Keep us in the loop....

**omcstratos** · 08-24-2013

I may try a transom pickup and get the bullet of the gearcase up out of the water more. I don't want to put a nose cone lwp on and create more drag if I can't run at a high enough elevation.

**fs5** · 08-27-2013

hi mate,see if you can get a good prop guy to cut a bit of diameter out of it and trim some off the blades.
sounds like a 12inch d prop would suit you better.maybe even a 11.5?