Tansom Width %

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Grimracer

Grimracer

Well-Known Member
Joined
Dec 27, 2001
Messages
9,501
IMPBA Members and Sport Hydro Racers.

I have been thinking about the idea of writing a proposal for a transom width percentage based on sponson to sponson width for sport hydroplanes..

I would like to here your thoughts on this.

Thanks in advance.

Grim
 
Last edited by a moderator:
Well Phil,

You know more then others that I really enjoy sport hydroplanes. I like my boats to have some character and i do my best to paint them up and make them look like a full scale boat..

My thinking is that I would like to protect sport hydroplanes as they are now and not let the class grow into a thingy class. We already kind of do protect it but as we progress with hydroplane design it would just be a good idea to do what we can now to protect the look of the boats.

Thanks and thoughts?

Cheers

Grimracer
 
Mike.... mike... mic mi... You know what kinda can you'll be openin' up? Like, You Got Another thing comin' Kudos, though, for still tryin to instill some kinda boundaries...... Wishin ya luck from here, already. Shhhh... dont' say, nor type words like: noise, decibel, bearing, electric, nats, measurement, etc, etc... everyone's kinda getting along! Now, I built my spt .21 to scale, and to the letter of existing rules, also, just cuz' I like the scale look also..... legal, I think... anywhere. Who knows.... throw it out there.. just my OP I could be wrong..... hang tight ..... mike
 
Grimracer said:
Well Phil,
You know more then others that I really enjoy sport hydroplanes. I like my boats to have some character and i do my best to paint them up and make them look like a full scale boat..

My thinking is that I would like to protect sport hydroplanes as they are now and not let the class grow into a thingy class. We already kind of do protect it but as we progress with hydroplane design it would just be a good idea to do what we can now to protect the look of the boats.

Thanks and thoughts?

Cheers

Grimracer
Click to expand...
Yes I dont want thingys either The rule we have now is good, not perfect but works. The more details you throw in the rules confuses everyone. The Namba and Impba have enough differences now.

You still making the Evansville race 5-19? We can talk about it there

PHIL T
 
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I kind of started a trend to make the transoms narrower. This is especially true with the gas sport hydros (seaducer and now the new Insane). There is nothing in the rulebook that says you can't have a 4" transom. I do agree with Mike about a percentage rule. This will keep the integrity of the class, as well as somewhat define what a "modified rigger" is. I for one am not going to open the can though.

Brian
 
P THOMAS said:
Yes I dont want thingys either The rule we have now is good, not perfect but works. The more details you throw in the rules confuses everyone. The Namba and Impba have enough differences now. You still making the Evansville race 5-19? We can talk about it there

PHIL T
Click to expand...
Actually the rule doesn't work as well as it should in the current verbage & is confusing to many. This is why the "modified rigger" arguement seems to resurface about every 90 days or so. I also have been thinking about a transom width percentage rule which would take away alot of that problem. In my opinion the thing to do at this point is look at the IMPBA hulls already deemed legal, take an average of them & go from there. Properly written to be easy to understand I would support this proposal. B)
 
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Ok, what do you mean by sponson width? Do you mean the width of the tunnel at the sponson to tunnel floor joint? Or do you mean the outside width at the widest point of the sponsons? Or do you mean the inside width of the ride surface? My point is that htere are many ways to interpret sponson width......... This will have to be nailed down.
 
Even though the bulk of them are messed up, the new NAMBA Electric Sport Hydro rules, which got inserted to the rulebook a year or so ago, specifies the following:

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.

Of course, then there is a vague exception that follows...

An exception to this will apply to scratch build scale designs of full

sized boats that are full bodied 3 points hydroplanes but have an

afterplane that tapers sharply at the transom. Example: Lauterbach

shovelnoses.

But the basic rule remains fairly clear... Now, how you deal with recessed transoms, etc., I'm not sure... A clear definition of "transom" might help, but would likely introduce all kinds of additional GRAY... :rolleyes:

The entire NAMBA Sport Hydro deal needs to be rethought and rewritten anyhow in my opinion... The attempt to update the FE side of the house resulted in a mess of GRAY in my opinion, but also included an updated idea of what Sport Hydro is... Hardware locations is more open, as are certain hull dimensions (belly pan), which allows more modern and recent designs (scaled after real Limited designs, etc...)...

It would be nice if we could all share the same rules... especially since the FE guys are starting to use the Nitro sized Sport 21 hulls... Would help keep the supply of hulls current and available...
 
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Tnrc

No question.. Thanks for your input.. is that all.. do you have any thoughts on if this is a good or bad idea?

Thanks

Grim
 
Grimracer said:
Tnrc
No question.. Thanks for your input.. is that all.. do you have any thoughts on if this is a good or bad idea?

Thanks

Grim
Click to expand...
NOW THATS WHAT IM TALKIN ABOUT "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" Plain simple easy to understand Mikey
 
Don Ferrette said:
P THOMAS said:
Yes I dont want thingys either The rule we have now is good, not perfect but works. The more details you throw in the rules confuses everyone. The Namba and Impba have enough differences now. You still making the Evansville race 5-19? We can talk about it there

PHIL T
Click to expand...
Actually the rule doesn't work as well as it should in the current verbage & is confusing to many. This is why the "modified rigger" arguement seems to resurface about every 90 days or so. I also have been thinking about a transom width percentage rule which would take away alot of that problem. In my opinion the thing to do at this point is look at the IMPBA hulls already deemed legal, take an average of them & go from there. Properly written to be easy to understand I would support this proposal. B)
Click to expand...
So you want to make exactly half of the current boats illegal? If you use an average that's what you would be doing.
 
Joe_Knesek said:
Don Ferrette said:
P THOMAS said:
Yes I dont want thingys either The rule we have now is good, not perfect but works. The more details you throw in the rules confuses everyone. The Namba and Impba have enough differences now. You still making the Evansville race 5-19? We can talk about it there

PHIL T
Click to expand...
Actually the rule doesn't work as well as it should in the current verbage & is confusing to many. This is why the "modified rigger" arguement seems to resurface about every 90 days or so. I also have been thinking about a transom width percentage rule which would take away alot of that problem. In my opinion the thing to do at this point is look at the IMPBA hulls already deemed legal, take an average of them & go from there. Properly written to be easy to understand I would support this proposal. B)
Click to expand...
So you want to make exactly half of the current boats illegal? If you use an average that's what you would be doing.
Click to expand...
What math are you using Joe?? What I suggested was starting with what's a legal average width & go from there. The point is to take what's currently legal into account before any numbers are reached. <_<
 
It seems like every time we mess with the rules we just make them more confusing yet less effective. Personally I think we need to go back to the basics with all of our rules. One thing that global Fortune 500 companies have in common is simple goal setting. We could learn from them.

And Don. It's simple math too. Go to dictionary.com for the definition of average. Maybe you should think about using minimum.
 
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OK.. that would work... Minimum..

Transom width would not be narrower then what percent of the inner front sponson width?

Transom being the total aft plane of the boat when viewed from behind, excluding front sponsons and cowl.. not sure thats right.. Help!

Lets get this right guys.. lets pull together and see what we can do..

grim
 
Grimracer said:
Transom width would not be narrower then what percent of the inner front sponson width?
Transom being the total aft plane of the boat when viewed from behind, excluding front sponsons and cowl.. not sure thats right.. Help!
Click to expand...

A couple of questions you need to ask:

1) What do you do about recessed transoms?

2) Is there an exception for scale boats that are designed after hulls that had a sharp cutback to the transom??

I'm fine with a percentage, and I think about 65% works pretty well... What you guys should do is get a data post going that lists a) Hull, B) width between the furthest aftmost inner edge of the ride-pad/planing surface of the sponsons, and c) transom width...

See what you have then figure out what you want...

Once you get that all fixed... you can start in on belly-pan dimensions! ;)
 
So is this something that is out of control & needs correcting? I personally haven't seen any evidence that the current rules aren't effective. What's the value added here? It seems like another flavor of the day discussion to me.
 
Darin- transom cut outs/recesses are not legal in IMPBA sport 40

Joe- it's just a matter of trying to get rid of some of that "gray area". Why does this seem to bother you so, are you in the middle of a "gray area" sport 40 build? :lol:

And once again the term average was used ONLY IN REFERENCE AS A STARTING POINT TO WORK FROM ON EXISTING BOATS, NOT THE RULE WORDING. :ph34r:
 
As for the transom width, do you define the max width, or the width on the bottom at the water contact surface? On my Betke-Berari SP40 the sponson ride surface width is 11 3/4" if I include the RH anti-trip chine, the tunnel width is 11 1/4", the overal transom width is 9", and the transom width at the bottom is 5 3/4" due to the large anti-trip chine on either side. By my calculations the ratio of my transom width is between 48.9% (11 3/4" sponson width with the 5 3/4" transom bottom) and 80.9% (11 1/4" sponson width with the 9" overall transom width) depending on which dimensions are used. My recommendation is to not include anti-trip chines in considering the widths. A square notch (>80 degrees) sponson or bottom surface corner cut out would be used as the width for the calculations. I'll try to post some pics later if warranted.
 
Last edited by a moderator:
Don Ferrette said:
Joe- it's just a matter of trying to get rid of some of that "gray area". Why does this seem to bother you so, are you in the middle of a "gray area" sport 40 build? :lol:
Click to expand...
Nope. It's just a standard Whiplash. I look at this as just another attempt to convert a sport class into a Scale class which it was never intended to be.

Again I ask do we have a problem? If not I see no reason to change the current rules.
 

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