Tansom Width %

[Paul Pachmayer]

Hi Guys,

We're having this debate right now for the new electric rules. Personally I'm not happy with it. The problem is there really is no problem with what we have now. Sure there have been guys that have pushed the limits but their far and few between. My best example is a shovel nose I just st a straight line record with. The boat is without a doubt a sport hydro and looks the part. Problem is that to control air flow the sponsons were notched similar to a Whiplash, this gave it a wider stance and bled air from the tunnel. Worked great but under the NAMBA rules it would be illeagal. That is a bunch of hooey.

Here's what is being proposed and it does address the problem above but it also could open other doors to the savvy builder.

Sport Hydro rules for IMPBA E- Classes

Sport Hydro

General

All boats to resemble Unlimited and/or Limited three-point, full-bodied hydroplanes (meaning no rear vents) as raced from the past or present. Fictitious teams may be created within the Spirit of the past and present Unlimited Hydroplanes. The word ‘resemble shall be loosely interpreted and as long as the boat is configured in the spirit of a real 3-point, full-bodied hydro, it shall be deemed legal.

Motor/Cells

A. All boats must be inboard motor powered.

B. All boats will conform to the power classes set out for E – Classes

Hull Configurations

A. Hull must conform to the three-point hydroplane configuration and resemble a real limited or unlimited hydroplane from the past or present. Outriggers, modified outriggers, canards, or tunnels are not allowed.

B. All boats must have some sort of markings affixed (such as sponsor names, logos, racing numbers) even if these names are fictitious. The hull appearance shall be in the spirit of resembling a real racing hydroplane.

C. The boat must have a driver figure and/or a simulated enclosed cockpit. A blacked-out canopy is allowed.

D. Both round-nose and pickle-fork hull styles are allowed

HULL SPECIFICATIONS

A. Hull length limitations

LSH – 23 inch Min

E-1 Sport Hydro Max 27 inches

E-2 Sport Hydro 27 to 35 inches

E-3 Sport Hydro 35 to 40 inches

E-4 Sport Hydro 40 to 60 inches

B. All riding surfaces (drive train and prop not included) must be in the front 50% of the total hull length.

C. A single triangular (from side profile) stuffing box for the driveline will be allowed as long as its primary purpose is to house the driveline and dimensions don’t unreasonably exceed that purpose.

D. Ride pads and/or steps are allowed but must be an integral part of the sponson design.

E. Picklefork hulls shall not have open areas ahead of the aft edge of the sponson riding surface totaling more than 25% of the total hull length.

F. No boat shall have an afterplane* greater than 60% of the total length of the boat. The afterplane will be measured from the back of the front sponson planing surface to the transom.

Note: The afterplane is the entire main hull aft of the sponsons; i.e. the "fuselage".

G. The width of the transom bottom shall be no less than 65% of the width between the inside edges of the front sponson planing surfaces.

For Shovelnose boats that have an afterplane bottom width that tapers sharply at the transom. The afterplane bottom must meet the 65% rule except for the last 3 1/2 inches were the bottom width tapers in sharply to the transom. Example: H+M Classic II sholvenose.

H. No rear shoes, Air dams that extend to the rear may be a Max 1/8 inches wide.

I. No rear vents.

J. Transom cut-outs not allowed.

Driveline

Struts, props and rudders may protrude beyond the transom.

Race Format

Oval heat racing rules will be used.

 

[Darin Jordan]

G. The width of the transom bottom shall be no less than 65% of the width between the inside edges of the front sponson planing surfaces.
For Shovelnose boats that have an afterplane bottom width that tapers sharply at the transom. The afterplane bottom must meet the 65% rule except for the last 3 1/2 inches were the bottom width tapers in sharply to the transom. Example: H+M Classic II sholvenose.

WHY only Shovel noses?? Seems kind of bias'd... Is there a reason why it should be limited to only shovels??

Another issue... A rule gets made, then the exceptions...

WHY can't the rule be made WITHOUT any acceptions?? If you make it 60%, or 62%... rather than 65%, then there wouldn't need to be any ecceptions for standard "look the part" hydroplane designs... The only things that would push the limits would be true "modified riggers" designs... and there wouldn't need to be any acceptions...

Just a thought...

I look at this as just another attempt to convert a sport class into a Scale class which it was never intended to be.

You might see it that way, but the rules start out by saying: "Hulls must be of Unlimited and/or Limited design,...", and they also require that you have a driver figure "of scale like appearance", and have the hull "attractively painted in the spirit of Limited or Unlimited inboard hydroplane racing."

The entire basis for the class stems from "scale"... the baseline references for the boat designs are "scale"... It's natural for people to then say, 'well, the Lobster boat is an "unlimited design", why can't I make a sport hydro based on that?'... It's a legitimate question and based on a "by the letter" reading of the rules, it can't be clearly answered "legal" or "not-legal"...

I think people just want some rules that are definitive and clearly state what is and isn't legal... Doesn't seem like an evil pursuit to me... I'd like to know just what limits I can design to without interpreting something then having it deemed illegal...

People try to stay "stay away from the gray"... but from my background (SCCA Sports Car Racing...), it's the racers job to bump up against the legal limits... tough to do that when they aren't clearly stated...

I'm all for some hard numbers, percetages, and clearly defined allowances...

 

[Grimracer]

This is not about backing in to anything for gods sake..lets keep this civil.

Its a QUESTION to see if we feel a percentage is a good idea or not.. if most feel its not then the post can rot down the board. If we feel it might benefit the IMPBA and the people that race and or build the boats then Im willing to give it a shot to write a proposal.

Grim

 

[Darin Jordan]

Its a QUESTION to see if we feel a percentage is a good idea or not..

I feel a percentage is fine... I'd go a step further and say that, looking at Paul's proposed FE rules above, even the exception should be based on a percentage (instead of "the last 3 1/2" it should be the "last XX%")... percentages allow things to be scalable to the size of the hull and keep things proportionately equivalent...

Determining WHAT percentage??? That's the real issue...

Clearly define where the measurements would apply/be-taken, and the rule should be easy to adhere to...

 

[Grimracer]

Im with you dude..

Im convinced it would better the IMPBA to have this in the Sport rules..

Hum..

Grim

 

[tnrcboatracer]

As I recall, when the IMPBA SP40 rules came out, the intent was to have a .45 powered hull that was scale in appearance, without having to go to the level of detail of the 1/8 Scale class. Hence bogus sponsors, limited/unlimited scale appearance, etc. As new hulls have come out there has often been the argument regaring the "modified rigger" clause. This is especially true if the hull really performed well against the current hulls. This was true of the B-B SP40 about 5 yrs ago; and it's still true today. I have a SP20 design I'm toying with building that will push the letter of the rules as well. I'll probably go ahead an build it just to see if it works as I think, and to see if the arguments regarding legality ensue.

I don't agree that any boats currently in production or raced prior to a rule change should be made illegal. They should be grandfathered in since they were legal under the specifications at the time they were built. That even includes the 1 example of the twin 21 that James put together in the late 90's. (I believe that Marty has that hull now) The rules were changed to specify single engine after the boat was raced a few times. I don't thibk it's right to rule someones ingenuity and hard work as illegal by changing the specs after the fact.

Back onto the topic at hand, I don't think that a transom spec is required (if it's not broke, don't fix it). This is a hobby for most of us. It sounds like we are trying to nail down design specifications like we are NASCAR of F1. Let's just go play boats.

 

[Darin Jordan]

Back onto the topic at hand, I don't think that a transom spec is required (if it's not broke, don't fix it). This is a hobby for most of us. It sounds like we are trying to nail down design specifications like we are NASCAR of F1. Let's just go play boats.

That's fine and dandy until someone decides to make something "unique" and perfectly within the rules (since there isn't one...), starts winning, then everyone starts complaining and whining because the design "doesn't meet the INTENT" or "Spirit" of the rules...

Don't think it happens??? It has and it will again...

 

[Joe_Knesek]

That's fine and dandy until someone decides to make something "unique" and perfectly within the rules (since there isn't one...), starts winning, then everyone starts complaining and whining because the design "doesn't meet the INTENT" or "Spirit" of the rules...
Don't think it happens??? It has and it will again...

Darin can you please follow up in on the incident mentioned above? I've never seen such an act in D2. Rules are aimed at big issues not the exception.

So far nobody has actually shared any empirical or even anecdotal evidence that we even have a problem.

 

[Darin Jordan]

Darin can you please fill up in on the incident mentioned above? I've never seen such an act in D2. Rules are aimed at big issues not the exception.
So far nobody has actually shared any empirical or even anecdotal evidence that we even have a problem.

Sure... No Problem... I'll do it by asking a question.

Can you tell me, based on the existing Sport Hydro rules for NAMBA, ignoring the Nitro specific sections (tuned pipe, etc...) if this boat would be a legal Sport Hydro?

This boat has participated in the NAMBA FE Nationals, won some hardware, and the owner was villified for not being "in the spirit" of the rules... This is just one example... There are others involving Shovels and boats that have truely been riggers with filler added between the sponsons... Clearly in the gray... No REAL solid way to say Yes or No...

Why would one want to try to operate under those types of rules?

Why would anyone want to put their neck out by developing more modern hulls when they have to do it to rules that are vaque at best??

 

[Paul Pachmayer]

Hi Guys,

I did not right or have anything to do with the rule proposal I posted. I'm more the moderator on it as it pertains to the new IMPBA FE rule proposal changes. I'm not in favor of it and i HATE exceptions to a rule. The reason shovels are in the exception is pretty simple, the anti-trips cut deep into the transoms and narrow way more than a picklefork design.

I think it's trying to over regulate a problem that really doesn't exist. The other one that bugs me is no vented hulls. Thinking a vented hull has some magic advantage over a more conventional design is really quite silly.

I'll go with the majority because I feel that's the fair way to do it but my vote is forget about it. It's really simple, if people know a CD will DQ a boat if it's to close to the gray area they won't build one. If it looks like a duck and quacks like a duck it's a duck.

Good example for you, the boat that was kitted recently by Bob (cant remember his name) that was built to the rule but looked like a rigger (kinda). He had to just about give them away, why, to close to the gray area. I've got one of them still in the box and it is what it is. BTW: no, I wont sell it. <_< I believe he went back to the drawing board to build a more "conventional' style boat.

Paul.

 

[Darin Jordan]

It's really simple, if people know a CD will DQ a boat if it's to close to the gray area they won't build one. If it looks like a duck and quacks like a duck it's a duck.

When the whole rulebook is "gray"... how do you know when you've gotten too close to it?

Can the hull "be of Unlimited or Limited design"... or can't it??? In my opinion, it's these vaque references that cause most of the issue... because there are both Unlimited and Limited designs that are essentially outriggers... or have vents... or have cutout transoms... Heck, it would be better if the rule just added "...with the following exceptions"... and then described the details of an "Unlimited or Limited design" that would not be allowed... But it doesn't do that...

It would be more concise if it instead gave a description of the hull design the class is designed around... and give some min or max dimensions for specific portions of the hull (picklefork cutout... vents... transom... belly pan... tunnel... whatever...).

Give these poor guys something concrete to design and build to, and this "issue" will go away for good... AND we'll have a good supply of hulls... Parameters for a class should not be THIS gray...

 

[Joe_Knesek]

It's really simple, if people know a CD will DQ a boat if it's to close to the gray area they won't build one. If it looks like a duck and quacks like a duck it's a duck.

When the whole rulebook is "gray"... how do you know when you've gotten too close to it?

Can the hull "be of Unlimited or Limited design"... or can't it??? In my opinion, it's these vaque references that cause most of the issue... because there are both Unlimited and Limited designs that are essentially outriggers... or have vents... or have cutout transoms... Heck, it would be better if the rule just added "...with the following exceptions"... and then described the details of an "Unlimited or Limited design" that would not be allowed... But it doesn't do that...

It would be more concise if it instead gave a description of the hull design the class is designed around... and give some min or max dimensions for specific portions of the hull (picklefork cutout... vents... transom... belly pan... tunnel... whatever...).

Give these poor guys something concrete to design and build to, and this "issue" will go away for good... AND we'll have a good supply of hulls... Parameters for a class should not be THIS gray...

Just a little snip from a requirements (rules) document that I thought I'd share. Requirements must always be feasible, necessary & unambiguous. The reader of a requirement statement should be able to draw only one interpretation of it. Also, multiple readers of a requirement should arrive at the same interpretation. Natural language is highly prone to ambiguity. Avoid subjective words like user-friendly, easy, simple, rapid, efficient, several, state-of-the-art, improved, maximize, and minimize. Words that are clear to the SRS author may not be clear to readers. Write each requirement in succinct, simple, straightforward language of the user domain, not in computerese. Effective ways to reveal ambiguity include formal inspections of the requirements specifications, writing test cases from requirements, and creating user scenarios that illustrate the expected behavior of a specific portion of the product.

 

[Darin Jordan]

Requirements must always be feasible, necessary & unambiguous. The reader of a requirement statement should be able to draw only one interpretation of it. Also, multiple readers of a requirement should arrive at the same interpretation.

I completely agree... Which takes me back to something Paul mentioned...

It's really simple, if people know a CD will DQ a boat if it's to close to the gray area they won't build one.

A set of rules should NOT be such that ONE person's interpretation, or opinion, will be the determining factor... How the heck is the competitor suppose to know what the CD thinks is and isn't legal... and should that competitor have to care?

multiple readers of a requirement should arrive at the same interpretation.

Exactly....

So, when one askes "is there a problem with what we have now???"... Ask yourself a question:

"If multiple readers read this rule, will they all arrive at the same interpretation?"

I think that is something to strive for... because right now, the rules are anything BUT that...

I do think, however, that the IMPBA FE rules are heading that direction, so I have to give a thumbs up to them for trying to get this done right for FE...

 

[Joe_Knesek]

I agree that the rules need to be cleaned up but I don't think we should start with a clean sheet of paper. Tweak what we have to remove ambiguity but do not make them any more restrictive then they already are. Take a look at the offshore rules. In my opinion they are even worse then the Sport rules.

 

[Darin Jordan]

I agree that the rules need to be cleaned up but I don't think we should start with a clean sheet of paper. Tweak what we have to remove ambiguity but do not make them any more restrictive then they already are.

Again, we agree... I'm just looking for them to be clear, unambiguous, and allow for development and creativity to keep things fun... All it would take is some tweaking...

 

[tnrcboatracer]

I just read the NAMBA Sprt hydro rules, and it appears that the transom width is specified in the dimensional table. For SP21 the minimum width is 4", for SP40 the minimum width is 5 1/2". I also read the FE sport rules, and see the 65% width requirement for the bottom surface. Interestingly, the FE rules allow certain specific hulls as well as some comments about scratch built hulls. I find too much ambiguity in the FE version of the rules. As for the photo of the hull in question, I think it should be a legal hull, as it is similar to an unlimited hull design that was raced. No issue there. Now if someone has sour grapes because they were beaten by this boat, that's their problem. Perhaps they should better their driving skills, or spend more time on hte water prepping their hardware. In my experience, the hull rarely wins a race, the skill of the driver and the prep of the setup is more important than the speed of the hull.

 

[Paul Pachmayer]

Hi Guys,

A set of rules should NOT be such that ONE person's interpretation, or opinion, will be the determining factor... How the heck is the competitor suppose to know what the CD thinks is and isn't legal... and should that competitor have to care?

Sorry guys, I guess I give the masses to much credit in knowing what a sport hydro is and what a rigger is. There's a really good picture of a sport hydro with the requirements Darin mentioned in the IMPBA rule book. If you look at that picture and build a filled in rigger to the letter of the rule it's legal by the dimentions but certainly isn't in the spirit of the class.

Again, I personally could care less if a person wanted to run a vented hull design or an over dressed rigger. It certainly hasn't been a huge problem in the past and I really don't see it as becoming a problem in the future. Peer presure goes a long way to resolving problems with trouble makers.

JMO but trying to micro manage a hobby with an iron clad set of rules is nothing short of impossible.

Paul.

 

[Andy Brown]

Has the IMPBA had any rule change on this "transom" thing? I personally hope it is a wide transom...

And what is a modified outrigger? LOL

What comes first the chicken or the egg?

A Lauterbach could become an Outrigger.

I cut my Dumas Dragonfly into an outrigger.

Good thing I didn't try to race a full bodied Dragonfly in Sport hydro after that!

 

[P THOMAS]

Yes there is a new set of rules to be in the rule book this year. the transom bottom cannot be less than 65% of the width of the front ride pad inside measurment.

 

[Andy Brown]

Yes there is a new set of rules to be in the rule book this year. the transom bottom cannot be less than 65% of the width of the front ride pad inside measurment.

I did not see that in the book under sport hydro section. Where must I look? Does it involve any taper? Or can the center drop to 65% right behind the sponsons?