MY thoughts on the Mini Most

[aojesus]

A 60-J runabout would be the perfect sized boat for a small outboard like the Briggs. Remember that the J's in those days did not go as fast as they do now and there was still great racing every time the J's hit the water. Plus, there were more J runabouts then because us kids could man handle the boats easier than the kids can now. Ever wonder why kids do not want to drive J runabout now???

I do not think the 60-J runabouts would be as easy to build as the mini-most but I'm sure some construction changes to that size boat could be made for an easier build.

Those were the days! My JSR was built by Mitch Meyer. It had no V at all in the bottom and a straight duck bill nose. My spray shield was the stainless steel soup ladle. It was a very forgiving boat, didn't porpoise, and could hit the blazing speed of 28 or 29 MPH. It felt like 129 MPH until I got my ASR. I learned a lot in that boat and had a blast doing it. I am not sure the brand, but I got to drive Brent Backus's JSR one day at Silver Lake and that handled very well also.

We had eliminations at the region 2 divisionals in JSR.

[woodman]

Replacing the lower unit (is what you are talking about right?) must be expensive. Is that the first thing to change out on outboards. What is wrong with the stock one ? To heavy, wrong gears , what?
You guys know this stuff in you're sleep, I am a wood worker-cabinet maker, getting my feet weat in boat building. And would like to get others interested in it.

How can they be called stock if the motors are modified?

On a jet ski motor (say kawasaki 650) you go with a high comp. head ,bigger card and manifold, after market exhaust ,cut back on the water geting into the exhaust and go with a stainles impeller and a less restrictive intake grate.
And all that runs into a few hundred bucks off ebay.

Back to the boat hull ,what about a 10'-11' tunnel hull.
Take the Glen-l Tunnel Mite and make it over .

[sam]

Replacing the lower unit (is what you are talking about right?) must be expensive. Is that the first thing to change out on outboards. What is wrong with the stock one ? To heavy, wrong gears , what?
You guys know this stuff in you're sleep, I am a wood worker-cabinet maker, getting my feet weat in boat building. And would like to get others interested in it.

How can they be called stock if the motors are modified?

On a jet ski motor (say kawasaki 650) you go with a high comp. head ,bigger card and manifold, after market exhaust ,cut back on the water geting into the exhaust and go with a stainles impeller and a less restrictive intake grate.
And all that runs into a few hundred bucks off ebay.

Back to the boat hull ,what about a 10'-11' tunnel hull.
Take the Glen-l Tunnel Mite and make it over .

There you are .... Mini GP

The motors are called "Stock" because once upon a time motors were sold by the major manufacturers with racing lower units

[jsilvestri]

Those were the days! My JSR was built by Mitch Meyer. It had no V at all in the bottom and a straight duck bill nose. My spray shield was the stainless steel soup ladle. It was a very forgiving boat, didn't porpoise, and could hit the blazing speed of 28 or 29 MPH. It felt like 129 MPH until I got my ASR. I learned a lot in that boat and had a blast doing it. I am not sure the brand, but I got to drive Brent Backus's JSR one day at Silver Lake and that handled very well also.

We had eliminations at the region 2 divisionals in JSR.

My best J runabout was an Austin. It had a flat bottom, duck bill nose and the center part of the top deck was cloth. I finished fourth in JSR at the 85' Dayton Stock Nationals and I set a record and won the nationals with it in JMR in 86'. That boat and the tub of a boat I had before it is what taught me how to drive a runabout, skills I still use today.

[PopPop]

Jsr

We are getting a bit off topic but most of todays fast JSRs are based on the "wedgie" design developed by Bud Pinto and Bob Minton. The boats have a wide bottom and sides that run straight up to become a peaked deck. The effect is to reduce the aerodynamic "deck lift" that was causing the wide bottom boats to blow over. The most popular of these were perfected and built by Philip DiFebo. They set a lot of records and won a lot of nationals when the water was "good". They have even run away with a few ASR races.

[Skoontz]

There is absoultely nothing wrong with running stock gear cases, as long as you write a rule placing a minimum width. So, you measure a Merc, OMC, Yamaha stock through hub gearcase diameters, require a F-N-R feature, that must shift, no grinding gears flat or using spacers to reduce drag, adopt a width, adopt a nose requirement, (no pointed nose cones) just like a stock gear foot is....You then experiment with engines, and if one is extremely faster than the next you require it to run lower in the water.

A similar concept will occur sometime this season in region 12 except rather than flat bottoms, we will be running hydros with deeper sponsons, taller transoms, and wider bottoms....You will see a boat/engine combo on the water for under $2,000.00 ready to race with the deciding factor of course being if used motors jump in price. Stainless props will be available for 15 Merc and OMC motors in 10-11-12" varieties for under $200 a piece, so no musical prop picks going on....

[csh2z]

The concept of one design hulls and pure stock motors is wonderful on paper, but in reality it has been tried, primarily in the OPC category with Mini-Grand Prix and Sport C, but hasn't worked out very well for the long term. The most significant reason for their demise is that the participants are racers/competitors that want to win! These relatively inexpensive classes evolved just like all our other classes. The only difference, after a few years of competitive people working to win, was the gearfoot. As time went on we ended up with boats that were massaged, motors that were blueprinted and custom made propellers. The cost of winning finally outweighed the value of the concept and these classes and most of the drivers eventually just disappeared. Throughout this evolution more and more rules had to be written to keep people from (cheating?) seeking unfair advantage over honest fellow competitors to the point that stock no longer meant stock. All stock classes, whether they be in Stock Outboard, OPC, Inboard, Offshore etc., in any racing organization APBA, AOF, NBRA, motorcycles, go-carts, cars etc. etc. have this one thing in common that causes this evolution......The desire to win!
These Mini-most projects sounds like good fun to introduce kids to boat racing and to give us another avenue to attract families to the sport but if not handled right could evolve into a problem.

[woodman]

modified 25hp

I found this interisting story............................................. ...............

http://www.nrkproductions.com/Tankar...ywood_boat.htm
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TANKAR's Tech Tips for small plywood boats.
Making the most of your mini-max or doodlebug type hull.
Horsepower; How much is enough? How much is too much?

The thing about horsepower with home made watercraft that makes decisions a little difficult is this question; How well did you or the original builder put the thing together in the first place?

The recommended horsepower according to plans I've read is from 5 to 15 horsepower. In my humble opinion, a 5 horsepower 2 cycle outboard might be enough for about 25 MPH with a driver less than 100 lbs in weight. That is if the kid drives good and the boat is built and set up to run properly. I have my doubts about any four cycle less than 10 horsepower pushing this boat fast enough for fun with 100 lbs aboard much less the weight of an adult between 100 and 200 lbs.

Why make a comparison even? When you are building a boat for speed and excitement you are going to need a high revving motor with lots of torque. Most 4 cycles below 10 horsepower fall far short of either standard. Your typical well tuned 2 cycle 5 horsepower will outperform the four cycle hands down.

One must also keep in mind the water, wind, and waves that this boat will be used on. This boat's size demands sheltered waters for safe fun. You can typically run the maximum of 15 horsepower in these ideal conditions with great success and few if any mishaps. I feel that this boat equipped with a 15 horsepower two cycle outboard and with a 175 lb. adult driver, under ideal set up and environmental conditions, could easily reach 30 or 35 MPH.

Warning: Do not try this at home unless you have good insurance. I take no responsibility for anyone doing what I have done by putting more horsepower on a boat than the hull is rated for and will in no way be held accountable for anyone else's foolishness in this regard.

I would never recommend going over rated or recommended horsepower ratings, but I must admit that I have done it myself (and eventually paid for it.) I actually have run a 25 horsepower and 35 horsepower Evinrude on the back of this style hull. I also came up with a hybrid 25 horsepower with a thirty five horse carb, intake, reeds, and lower unit with a modified exhaust. This motor revved up REAL QUICK and could actually shoot my hydro right out of the water in about a 15 foot jump from a dead standstill ! It was this motor's performance that eventually led to a flip accident that occurred when I punched the throttle just as a wake from a passing cabin cruiser was starting to rise and break in the shallow water I was riding in. The boat literally kited 360 degrees and I got pretty wet. After getting back in the boat I noticed it was swamped and I started to bail out the cockpit with my hands. I also saw that the motor board had ripped almost all the way free from the hull. There were only a couple of bent screws still holding it and the motor on. Just then a local seaplane ride operator who saw the whole thing happen taxied over to make sure I was still alive. He ended up giving me a tow back to the dock.

How did that little hull keep from sinking at a standstill with a massive 35 horse Evinrude Big Twin hooked over the transom? Read the story about how it was done by clicking this sentence.

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Copyright 2003, Three Tug Publishing
All Rights Reserved
Do not reproduce without permission.
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TANKAR's Tech Tips for small plywood boats.
Making the most of your mini-max or doodlebug type hull.
25 and the hybrid:
Warning: Do not try this at home unless you have good insurance. I take no responsibility for anyone doing what I have done by putting more horsepower on a boat than the hull is rated for and will in no way be held accountable for anyone else's foolishness in this regard.

After looking around I decided that a 1950's era 25 horse Evinrude Big Twin at a local dealers establishment was priced right and got it really cheap. This gentleman was a specialist in old outboards and outboard parts and I had done business with him since I was a kid racing hydros. I knew that the motor I bought from him had low hours because I had seen it in his shop since about 1967. It had a 25 horse cowl on it and a smaller carb, and after replacing the head gasket I confirmed that it had a smaller displacement than my larger bored 35 horse cylinders. It was also an electric start model and I gave it the same weight reduction course that my earlier 35 horse received short of the lower unit mod.

Lighten up the port side.
Lighten up the starboard side.
Lighten up the lower half and another view of the lower unit mod that ended up on the hybrid.

It was basically just a super stripped stock 25 horse outboard with no performance mods when I first hung it on the transom. I took it out and although it had plenty of pep, it didn't seem to really get up and move out or have quite the top speed of the old 35 horse. I couldn't afford another bigger motor so I checked things out a little closer. Upon further examination I realized that I could simply remove the smaller manifold, carb, and reeds and replace them with the ones off of my old 35 horse because the manifold was the same shape as both the 25 and the 35 horse block. In other words, the two blocks that I had could interchange intake manifolds with a simple bolt off/bolt on process. The only difference in the two intakes was the carb inlet diameter and the reed size. I bolted on the bigger equipment and then thought about the exhaust. I wondered.....Would the old modified lower unit bolt on as well? IT DID!

I actually had to replace some of the timing linkage that worked the advance with the throttle as well if I remember correctly which was also a simple swap.
After I got done messing with my experimental hybrid I put it in the test tank and it freakin' started right up on the first pull! Just to make sure that I wasn't hallucinating I shut it off and pulled it again. It started again on the first pull. I made sure that the water pump was pumping and then I shut it off and collected my thoughts. This motor seemed to rev like crazy and was a little "kicky" at idle. Throttle response was scary. It was immediate. I couldn't really rev it out in the test tank though and top RPMs weren't going to be had until the motor was on the hull and up on plane where I could adjust the high speed jets with full advance on the timing. I put the motor on the hull and got up to Nettle Lake in the extreme N.W. portion of Ohio for it's first test runs. After putting the boat in on the beach I pulled the starter rope and the motor fired up. I headed for deeper water and turned around to adjust the idle jets screw.

After leaning the screw until the motor coughed then giving it 1/4 turn back rich it was time to push the throttle open all the way for the first time. I slowly brought the hull on plane then pushed it until it seemed to be "lugging". That told me that I needed to lean it down some so I turned around and started leaning out the mixture. After about a half a turn the motor really started cranking out some revs and it really took off. I pulled the dead mans throttle wide open and re-adjusted the mixture a little more. By this time the boat must have been going 40 MPH or more and I was running out of lake already. I headed back varying my throttle position on the way to see if my final adjustment was good over the entire RPM range (which seemed to be the highest RPMs I have ever seen an Evinrude turn.)

I pulled up in front of the campground where I had launched from and a crowd was watching. I decided to show off a little. I came to a dead stop and then I just punched the throttle. This was when I found out that I really needed to hold on tight to this boat at times. The boat jumped about 10 or 15 feet right out of the water reaching a height of about 3 feet in the air. After a few more high speed runs up and down the lake it was quiet time there with a no wake limit enforced by a water patrol sheriff.

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Images and text
Copyright 2003, Three Tug Publishing
All Rights Reserved
Do not reproduce without permission.
Links permitted

[makeshiftboats]

i was bored browsing through old threads and stumbled on to this one that intersted me.i dont want to voice my opinion but would rather just state my experiense.i witnessed my first hydroplane race only four years ago.i told everyone i spoke to i wanted to race.cofee guy sold me a boat in 05 for a price our low budget could afford.three years later the boat sits because we cant stretch that far on christmas to buy a foot.the only time the boat gets on the water is when we get together to race mini maxes.i have since put together a sluggish dmod hydro and i started racing last year in constantine.as mentioned i was new to the sport 5 years ago.but i used mini max "racing" with my friends to get their feet wet and turn dozens of people in my community on to this sport.i brought 15 people to constantine in 07 and our numbers are growing.our mini max racing club has grown to 12 members with every one building a boat for the spring.last summer we had 6 drivers and all of them are gun hoe about getting in faster rigs traveling and racing with our group.so mini max has been my primary tool for getting others involved.its easy to put together its cheap it makes racing a boat something a poverty level inner city kid can afford to do as long as grandpa has an old merc in the attic.a good point to be made is that shortening the coarse has been our sollution.it keeps the action right in front of the spectaters.the water gets rough on a 1/8 mile coarse and racing is racing...ill bet my snail can beat yours!!!!