Thunder Boat Rules

[SayMikey]

If you have been over to Jims you might have seen all the talk about the new RCMK EVO Here are the current rules as they have been in effect since voted in late in 08. You will note RCMK is missing the s-254 was later deemed legal for Super Sport Engines. This DOES NOT INCLUDE THE EVO. Classic Thunderboat Hydro - Specialty Class

GENERAL DESCRIPTION – Scale or standoff scale replicas of the classic era (1950-1970)

Unlimited & Limited hydroplanes. All boats will be three (3) point hydroplanes, no outrigger;

modified outrigger, tunnel or canard hulls will be allowed.

HULL SPECIFICATIONS

1. Boats may be wood or fiberglass/composite type construction.

2. Length shall be a maximum of 56 inches, minimum of 47 inches. Width shall be a minimum

of 22 inches.

3. All boats shall have a front or rear cockpit with driver figures from the 1950’s - 1970’s era, no

cartoon or animal characters.

4. All boats shall have a period correct paint scheme and sponsor name & logo. The Sponsor

and/or logo may be original or of your own choice.

5. Normal hull configuration shall be conventional round nose, shovel nose, dropped sponson

or pickle fork design. The pickle fork shall not exceed 10% of the hull length and be

modeled after a classic era boat (1950-1970).

6. No rear sponson, ride shoe or other riding surface allowed aft of the sponson transom.

Engine belly pans are allowed. Engine belly pans may not extend beyond the engine

compartment.

7. Nothing may extend more than 5 1/4 inches beyond the transom.

8. The strut mounting is optional. Maximum strut length of 3 ½ inches in length and ½ inch in

width.

9. A minimum 50% of the gasoline engine must be covered with either a cowling or period correct

fake engine. This does not include header and/or tuned pipe.

ENGINE SPECIFICATIONS

IMPBA Super Sport Engine specification rules, as outlined in the IMPBA rulebook

Section I - Large Scale Gasoline will apply with the following exceptions.

1. Engine selection shall be limited to Zenoah or CY (SIKK) motors with 26cc max. displacement.

2. Any exhaust system allowed. The exhaust system must be concealed within the hull and may

exit from rear, side or bottom. Only the outlet may show. All boats must meet current IMPBA

noise rules.

3. An unmodified Walbro #257 carburetor may be substituted for the factory original carburetor.

4. Any composite or copper type replacement gasket set may be used but must be minimum

.014” to maximum .018” thickness.

The engine must be equipped with a recoil starter and this starter must be the primary means of

starting the engine. Supplementary starters are allowed. The brand of starter is optional.

 

[Bigbird]

Hey Mike

I have a copy of these rules from the 1 year trial period. My problem is I can't find these rules anywhere in the current IMPBA rule book. It was my understanding that these rules as they are above, were voted down, so clubs have been setting their own rules based on the 1 year trial. In Madison, we have been running the EVO RCMK in our thunderboats.

Bird

 

[dschigoda]

...In Madison, we have been running the EVO RCMK in our thunderboats.

Bird

Where could I buy an EVO RCMK? About how much do they cost? (I'm not seeing any mention of "EVO" on the RCMK website.)

What are some of the reasons that the Madison club chose this over the other engines out there?

 

[Bigbird]

...In Madison, we have been running the EVO RCMK in our thunderboats.

Bird

Where could I buy an EVO RCMK? About how much do they cost? (I'm not seeing any mention of "EVO" on the RCMK website.)

What are some of the reasons that the Madison club chose this over the other engines out there?

We get them from gizmomotors.com, the EVO is the new RCMK. It is rated at almost twice the hp of the Zenoah in stock form. So if the thunderboat rules say stock engine this would be an exceptable engine.

 

[Don Ferrette]

Below are the IMPBA Thunderboat rules as PASSED by membership and printed in the IMPBA Roostertail-

Classic Thunderboat Hydro - Specialty Class

 

GENERAL DESCRIPTION – Scale or standoff scale replicas of the classic era (1950-1970)

Unlimited & Limited hydroplanes. All boats will be three (3) point hydroplanes, no outrigger;

modified outrigger, tunnel or canard hulls will be allowed.

HULL SPECIFICATIONS

1. Boats may be wood or fiberglass/composite type construction.

2. Length shall be a maximum of 56 inches, minimum of 47 inches. Width shall be a minimum

of 22 inches.

3. All boats shall have a front or rear cockpit with driver figures from the 1950’s - 1970’s era, no

cartoon or animal characters.

4. All boats shall have a period correct paint scheme and sponsor name & logo. The Sponsor

and/or logo may be original or of your own choice.

5. Normal hull configuration shall be conventional round nose, shovel nose, dropped sponson

or pickle fork design. The pickle fork shall not exceed 10% of the hull length and be

modeled after a classic era boat (1950-1970).

6. No rear sponson, ride shoe or other riding surface allowed aft of the sponson transom.

Engine belly pans are allowed. Engine belly pans may not extend beyond the engine

compartment.

7. Nothing may extend more than 5 1/4 inches beyond the transom.

8. The strut mounting is optional. Maximum strut length of 3 ½ inches in length and ½ inch in

width.

9. A minimum 50% of the gasoline engine must be covered with either a cowling or period correct

fake engine. This does not include header and/or tuned pipe.

ENGINE SPECIFICATIONS

IMPBA Super Sport Engine specification rules, as outlined in the IMPBA rulebook

Section I - Large Scale Gasoline will apply with the following exceptions.

1. Any exhaust system allowed. The exhaust system must be concealed within the hull and may

exit from rear, side or bottom. Only the outlet may show. All boats must meet current IMPBA

noise rules.

2. An unmodified Walbro #257 carburetor may be substituted for the factory original carburetor.

3. Any composite or copper type replacement gasket set may be used but must be minimum

.014” to maximum .018” thickness.

The engine must be equipped with a recoil starter and this starter must be the primary means of

starting the engine. Supplementary starters are allowed. The brand of starter is optional.

Please note the engine section specifies using legal SuperSport engines with the listed exceptions allowed like the #257 carb. The IMPBA Technical Director has ruled that the Evo version of the RCMK S-254 is not a legal SS engine therefore it is not legal in the thunderboat class. The original baseline S-254 was recognized as a legal SS engine last winter. Hope this helps clarify things for everyone.

 

[Bigbird]

So as i read it, a stock engine of unspecified manufacturer is legal. When will this be placed in the rule book? I don't under stand how you can say that the RCMK is not a stock engine, when that is the way you get it from the factory. You can't make a rule that limits you to a single manufacturer. The only reason that I am arguing the point is if I made this engine, and you made a rule that all the people in IMPBA could not use my product for a stock class, I would be very upset. So in order for the RCMK to be competitive, and the only way you can use it is to buy one and modify it. Does not make sense to me...

BB

 

[Bigbird]

I also know that several people in Hobart In last weekend, ran RCMK EVO engines in their thunderboats.

 

[Ray Sametz]

I also know that several people in Hobart In last weekend, ran RCMK EVO engines in their thunderboats.

Whole other can of worms,Tech director and Gas director say the motor is not legal.

 

[Bigbird]

I also know that several people in Hobart In last weekend, ran RCMK EVO engines in their thunderboats.

Whole other can of worms,Tech director and Gas director say the motor is not legal.

It's a can of worms that needs to be opened...

 

[Denis Tomicki]

Was looking to get one!

Help fill in the time waiting around the pits with only 1 boat.

But the stock part leaves the door open. And keeping me from throwing down the $$

Stock but buy what standard! Someone's gotta Etch in stone the agreed HP rating!

A small worm; are they using there own castings to make this 2x hp engine? if so that would be stock.

And the bar just moves on up :unsure:

 

[Buddy Benedict]

Well Bird, If you want to talk nitro motors. CMB makes an outboard 21 BUT you cant run it in sport tunnel. Why!!!Because its the RULES. You can't run a CMB 26 or the Quickdraw 26 in Thunderboats WHY!!!! because it's the RULES. Hey nobody is stopping you from running one at you own little pond but don't start crying and whining if you are racing at another lake and somebody protests your boat because you are not following the RULES.

One thing you have to remember is we are all just racing TOY BOATS TOY BOATS TOY BOATS

Buddy

 

[larcor69]

I knew that new EVO was going to open a can of worm's, I asked about it 2 months ago and was told at that time, it's a stock engine, which it is, but it's way more advanced than the other's, Glad I got the older version in mine!! but I will have an EVO in my sport hydro next year!!

 

[jken1995]

Hey guys, Not trying to steal the thread, but I do have one quick question. I am very interested in this class after seeing the boats run in Hobart. Is that the only race that has this class in the Chicago and neighboring areas?

thanks, Jeff

 

[dschigoda]

I realize that making rules and communicating these rules can be a difficult and thankless task.

That being said - Has anyone given any thought to what will happen in a couple of years when Zenoah and Sikk update their engine designs and put them on the market?

How will it be determined whether or not the updated engines are legal?

How likely would it be that Zen or Sikk would continue to produce the old design, and continue to supply spare parts for the old version? Carrying double the inventory for parts these days may not be financially supportable for very long for these companies.

Does the IMPBA have better way of getting the word out on engine rulings? - other than "accidentally" reading about on the IW Forum?

Should a Thunderboat racer just assume that he may need to invest in a new engine every couple of years or so, depending on what develops between the rule making process and the manufacturer's advancements?

 

[Bigbird]

I realize that making rules and communicating these rules can be a difficult and thankless task.

That being said - Has anyone given any thought to what will happen in a couple of years when Zenoah and Sikk update their engine designs and put them on the market?

How will it be determined whether or not the updated engines are legal?

How likely would it be that Zen or Sikk would continue to produce the old design, and continue to supply spare parts for the old version? Carrying double the inventory for parts these days may not be financially supportable for very long for these companies.

Does the IMPBA have better way of getting the word out on engine rulings? - other than "accidentally" reading about on the IW Forum?

Should a Thunderboat racer just assume that he may need to invest in a new engine every couple of years or so, depending on what develops between the rule making process and the manufacturer's advancements?

Very well said.

Thank you...

BB

 

[BDM Racing]

I realize that making rules and communicating these rules can be a difficult and thankless task.

That being said - Has anyone given any thought to what will happen in a couple of years when Zenoah and Sikk update their engine designs and put them on the market?

How will it be determined whether or not the updated engines are legal?

How likely would it be that Zen or Sikk would continue to produce the old design, and continue to supply spare parts for the old version? Carrying double the inventory for parts these days may not be financially supportable for very long for these companies.

Does the IMPBA have better way of getting the word out on engine rulings? - other than "accidentally" reading about on the IW Forum?

Should a Thunderboat racer just assume that he may need to invest in a new engine every couple of years or so, depending on what develops between the rule making process and the manufacturer's advancements?

Yes very well said.

But as Don and Mike have said, and i havent heard anyone else in authority, Because RCMK, IMPROVED THEIR MOTOR, and its not on the IMPBA approved motors List. They are final, they are the written rule amd what they say we all must comply.

So if its not legal, Whats the step to GET IT LEGAL??

Steak & CHampane dinners, Take Mike to the local Gentlemans club, to help him *Tech* the motor, invite Don & Mike along with their families to a weekend in Vegas? WHAT????

I may not agree with either one of them, because RCMK, just improved their cylinder timings ever so slightly and the motor is still the S-254 design, but whats it gonna take for or IMPBA appointed Technical Review person to review the motor and make his recomendation?

Sorry,(IMHO) the current IMPBA B.O.D is not helping this hobby or its membership, when boat hull,electronic, or motor technolgy is improving and going forward, and we cant seem to determine if its legal, or is allowed.

Do all the new boat hulls, mono, hydro, thunderboat,etc.etc, have to be put before some Tech committe before its allowed to participate in IMPBA sanctioned events?

I see all these generations, 1,2,3 so on and on, of sport hydro,mono etc. are these approved? Everytime some hydro builder improves their sponson design, or a new prop is made avaliable, does it have to be approved?

Was the 2.4 GHZ radio go thru Tech approval,If it did, im not able to find it in the current rule book.

What would be nice if Mike would explain just what was so different about the S254 evo motor that has deemed it illegal, or confere will B.O.D since this motor was released after their once a year meeting.

Im sure some may not like what i have said, to make ALL happy, and maybe understand just what our IMPBA Technical Director is for, explain or give us a fix on this RCMK EVO motor so the ones that want to buy it and try it out can do so.

Bob Morrow

 

[SayMikey]

I realize that making rules and communicating these rules can be a difficult and thankless task.

That being said - Has anyone given any thought to what will happen in a couple of years when Zenoah and Sikk update their engine designs and put them on the market?

How will it be determined whether or not the updated engines are legal?

How likely would it be that Zen or Sikk would continue to produce the old design, and continue to supply spare parts for the old version? Carrying double the inventory for parts these days may not be financially supportable for very long for these companies.

Does the IMPBA have better way of getting the word out on engine rulings? - other than "accidentally" reading about on the IW Forum?

Should a Thunderboat racer just assume that he may need to invest in a new engine every couple of years or so, depending on what develops between the rule making process and the manufacturer's advancements?

Yes very well said.

But as Don and Mike have said, and i havent heard anyone else in authority, Because RCMK, IMPROVED THEIR MOTOR, and its not on the IMPBA approved motors List. They are final, they are the written rule amd what they say we all must comply.

So if its not legal, Whats the step to GET IT LEGAL??

Steak & CHampane dinners, Take Mike to the local Gentlemans club, to help him *Tech* the motor, invite Don & Mike along with their families to a weekend in Vegas? WHAT????

I may not agree with either one of them, because RCMK, just improved their cylinder timings ever so slightly and the motor is still the S-254 design, but whats it gonna take for or IMPBA appointed Technical Review person to review the motor and make his recomendation?

Sorry,(IMHO) the current IMPBA B.O.D is not helping this hobby or its membership, when boat hull,electronic, or motor technolgy is improving and going forward, and we cant seem to determine if its legal, or is allowed.

Do all the new boat hulls, mono, hydro, thunderboat,etc.etc, have to be put before some Tech committe before its allowed to participate in IMPBA sanctioned events?

I see all these generations, 1,2,3 so on and on, of sport hydro,mono etc. are these approved? Everytime some hydro builder improves their sponson design, or a new prop is made avaliable, does it have to be approved?

Was the 2.4 GHZ radio go thru Tech approval,If it did, im not able to find it in the current rule book.

What would be nice if Mike would explain just what was so different about the S254 evo motor that has deemed it illegal, or confere will B.O.D since this motor was released after their once a year meeting.

Im sure some may not like what i have said, to make ALL happy, and maybe understand just what our IMPBA Technical Director is for, explain or give us a fix on this RCMK EVO motor so the ones that want to buy it and try it out can do so.

Bob Morrow

Any time you want to bend the rules all you need to do is put it on the race flyer. If we dont stop all this soon we will just have 2 sport hydro classes. Is there an answer there are many,the solution just needs to be one that keeps the class alive and healthy. Maybe we should change the rules to any 27 motor even just drop the super sport rules in the trash. These boats were not supposed to be 60 mph monsters but are headed that way.

 

[Hydro Junkie]

I realize that making rules and communicating these rules can be a difficult and thankless task.

That being said - Has anyone given any thought to what will happen in a couple of years when Zenoah and Sikk update their engine designs and put them on the market?

How will it be determined whether or not the updated engines are legal?

How likely would it be that Zen or Sikk would continue to produce the old design, and continue to supply spare parts for the old version? Carrying double the inventory for parts these days may not be financially supportable for very long for these companies.

Does the IMPBA have better way of getting the word out on engine rulings? - other than "accidentally" reading about on the IW Forum?

Should a Thunderboat racer just assume that he may need to invest in a new engine every couple of years or so, depending on what develops between the rule making process and the manufacturer's advancements?

Yes very well said.

But as Don and Mike have said, and i havent heard anyone else in authority, Because RCMK, IMPROVED THEIR MOTOR, and its not on the IMPBA approved motors List. They are final, they are the written rule amd what they say we all must comply.

So if its not legal, Whats the step to GET IT LEGAL??

Steak & CHampane dinners, Take Mike to the local Gentlemans club, to help him *Tech* the motor, invite Don & Mike along with their families to a weekend in Vegas? WHAT????

I may not agree with either one of them, because RCMK, just improved their cylinder timings ever so slightly and the motor is still the S-254 design, but whats it gonna take for or IMPBA appointed Technical Review person to review the motor and make his recomendation?

Sorry,(IMHO) the current IMPBA B.O.D is not helping this hobby or its membership, when boat hull,electronic, or motor technolgy is improving and going forward, and we cant seem to determine if its legal, or is allowed.

Do all the new boat hulls, mono, hydro, thunderboat,etc.etc, have to be put before some Tech committe before its allowed to participate in IMPBA sanctioned events?

I see all these generations, 1,2,3 so on and on, of sport hydro,mono etc. are these approved? Everytime some hydro builder improves their sponson design, or a new prop is made avaliable, does it have to be approved?

Was the 2.4 GHZ radio go thru Tech approval,If it did, im not able to find it in the current rule book.

What would be nice if Mike would explain just what was so different about the S254 evo motor that has deemed it illegal, or confere will B.O.D since this motor was released after their once a year meeting.

Im sure some may not like what i have said, to make ALL happy, and maybe understand just what our IMPBA Technical Director is for, explain or give us a fix on this RCMK EVO motor so the ones that want to buy it and try it out can do so.

Bob Morrow

Any time you want to bend the rules all you need to do is put it on the race flyer. If we dont stop all this soon we will just have 2 sport hydro classes. Is there an answer there are many,the solution just needs to be one that keeps the class alive and healthy. Maybe we should change the rules to any 27 motor even just drop the super sport rules in the trash. These boats were not supposed to be 60 mph monsters but are headed that way.

I think the only way to solve this would be to limit the boats to the old G230 and call it good. That way the people building them would have to watch every miligram of weight that goes into the boat to get the maximum speeds or have a total snail on their hands

 

[Denis Tomicki]

That way the people building them would have to watch every miligram of weight that goes into the boat

Ya a weight cap would be a easy way to watch over the class! Simple digital bathroom scale in case there is a protest.

The stock engine? What is one? Ok if your talking dueling pistols them ya get a stock model like the other guy.

Weight will keep this class of boats running at there edge. Let the other guy blow over.

 

[fishinghole]

Here's my problem right now. Going to soon be building a Thunder Boat and don't want to throw good money into a new motor only to find out down the road it's not legal or on the other hand not competitive. If these rules are not in black and white and officals at Hobart allowed the Evo to run what I'm I suppose to do? I'm not trying to stir up a hornets net....really....but which way do I go? The problem here started when they allowed a S-254 into the class in the beginning. Didn't these motors have an edge on the Zenoah's right from the start? My other thought here is to a similar problem thats coming up soon.... what are they going to do when Crazy Al's, (Rossi), new 21 outboard shows up with it's own factory lower unit. By the rules it goes to B Sport Tunnel and or B Tunnel. That will shake things up when we find them in Sport running against stock K&B's and OS 21XM's don't you think? Mr. Brown of CMDI had the same intensions in his new line of motors as he was going to produce a motor with factory lower for Sport 20 tunnel. Someone's got to get this resolved without holding back technology. Just my 2 cents guys right or wrong. Have a good one.

J. Pflueger