December 2013 IMPBA Roostertail is online

[Chilli]

New issue of the Roostertail is online. We have new FE safety rules pertaining to class voltages during record trials events. There are also some rules proposals to vote on. Thanks to Chris Harris the National FE director and Doug Smock the records director for their work!!

http://www.impba.net/attachments/art...EE%20Final.pdf

[HOTWATER]

Hopefully online voting will be up on the website soon!

[don ferrette]

The on line voting on the IMPBA web site is now available but you must be registered on the site. If you are not registered yet please do so not only to vote but the web site holds a vast amount of good information for IMPBA boaters. Also even though a number of the rule proposals to vote on are regarding IC power they are still important and I'm hoping all will vote on and support the proposals especially the strut location on sport 40s. That is the only class that currently does not allow transom mounted struts like every other sport hydro class in the IMPBA does and I'd like to see consistency among those rules. Thanks in advance to all members who take the time to vote and make their voice heard.

[keithbradley]

Thanks to Doug, Chris, and all others involved in getting us a solid standard for starting voltage in FE classes. This was greatly needed IMO not only in regards to the integrity of our records, but as a means of simplifying what was a somewhat confusing classification. 4.23v/cell is straight-forward and completely reasonable.

I would like to ask, to any onlookers who might have the info:

Does the -17% figure still apply to minimum voltage, or is the minimum voltage for a class just based on the upper limits of the next lowest class?
For example, Q classes are limited to 4.23v * 6 (25.38v) max. Does that mean that the voltage parameters for S are 25.39v-33.84v? It may seem like an odd question, but it's not unlikely for a Q boat to run 5s, or a S boat to run 7s, T boat to run 9s, etc.

[Doug Smock]

Thanks to Doug, Chris, and all others involved in getting us a solid standard for starting voltage in FE classes. This was greatly needed IMO not only in regards to the integrity of our records, but as a means of simplifying what was a somewhat confusing classification. 4.23v/cell is straight-forward and completely reasonable.

I would like to ask, to any onlookers who might have the info:

Does the -17% figure still apply to minimum voltage, or is the minimum voltage for a class just based on the upper limits of the next lowest class?
For example, Q classes are limited to 4.23v * 6 (25.38v) max. Does that mean that the voltage parameters for S are 25.39v-33.84v? It may seem like an odd question, but it's not unlikely for a Q boat to run 5s, or a S boat to run 7s, T boat to run 9s, etc.

Thanks Keith and Mike!
Not a odd question at all Keith.
Here are the new class voltages that will appear with the update of the rulebook. The +/- 17% will go away.

N- 3.7 to 8.46
P- 11.1 to 16.92
Q- 18.5 to 25.38
S- 25.9 to 33.84
T- 33.3 to 42.30

[keithbradley]

How are the lower limit numbers determined? I can't seem to find a pattern that fits all classes...
The T range seems tighter than the other classes for some reason. For example, you could run 7s at as low as 3.7v/cell in S, but a 9s setup with cells at 4.1v each would not qualify for T.

If I follow the pattern for classes N through S, T should be 33.3v to 42.3v. Are you sure that wasn't a mistake?

[Doug Smock]

Are you sure that wasn't a mistake?

I was just making sure you were paying attention.
See above

[T.S.Davis]

Question.

With NAMBA, if I have a 33.5" boat and I drop 5s in....it becomes a Q boat. Is that how it works in IMPBA too?

[Fluid]

Not in IMPBA Sport Hydro. Your 5S boat would be illegal to race in any Sport Hydro class.


.

[Chilli]

A Q Sport Hydro has to be greater than 34 and up to 40 inches in length to be legal in the IMPBA. All other Q classes just have the 40" max.

[T.S.Davis]

Think I got it. Lower limits on the sporties.

Makes sense to a degree. All the boats will be similarly sized and powered. Provides parity and that scaley "look". I know the "look" factor has always been subject to debate but I'm okay with it.

[Shooter]

Does IMPBA have a (transom)/(sponson ride width) ratio rule? I just layed out a Whip 40 and it calculates to exactly 0.65. (8.5"/13"). This is at the exact minimum limit for NAMBA!

[Chilli]

From the IMPBA rule book, Section J: http://impba.net/attachments/article...ric%202013.pdf
The width of the bottom of the transom must be 65% or more of the width between the forward riding surfaces. On a shovelnose hull that has a tapered transom bottom the 65% rule will apply to the hull bottom at a point three a one half inches forward of the transom.

[keithbradley]

A Q Sport Hydro has to be greater than 34 and up to 40 inches in length to be legal in the IMPBA. All other Q classes just have the 40" max.

What's the reasoning behind a minimum hull length in sport hydro?

[T.S.Davis]

I can't speak for IMPBA but I do remember the conversation back when we were cooking limits.

Sport is thought of by some as a watery version of scale. Full bodies hydros that look similar in size and shape. Less restrictive than scale but still sorta scale looking. Hence the ratio limitations we have in NAMBA. We were trying to keep the riggers out of sport hydro.

When we chose not to have the lower limit in NAMBA we were thinking that guys could cross over. Maybe run 6s in a P boat so a traveler could run another class. The reality seems to have dictated otherwise. A 33" hull on the power that's available in at 6s simply will not finish. In traffic after maybe 2 laps of chop......not gonna happen. So nobody messes with it.

The only place I think you might be able to exploit the lack of a lower limit is SAW. Once upon a time there was a Q Sport saw record in IMPBA that was set by a little tiny sport shovel. It held for years. I'm guessing they were trying to avoid that.

Wild speculation on my part. Maybe Doug will remember.