Is this still a mono?

[NeilSharman]

You'd have to the the the break in the outer streaks would just cause drag in corners anyway right?

I wonder what the purpose was with the breaks in the strakes?

 

[Christian Lucas]

Hi John,

yes lengh is we all forgot . So i think about to move the batterie forward by servo after speed build up .

But Ralf Mosers record monohull is moore a bumblebee than a sting wasp . He has this big Gurnny flap at the transom doing a lot of aero stabilisation ,hold down the boat . It workes like a spoiler wing but look not like it . Cause a lot of drag but better to run a smoth not jumping cow .

Happy Amps Christian

 

[Darin Jordan]

You'd have to the the the break in the outer streaks would just cause drag in corners anyway right?

I wonder what the purpose was with the breaks in the strakes?

On the boat in question (original posting), it's simply to give the appearance that the boat is a stepped hull. The boat in question is a semi-scale representation of a read Phantom offshore boat. They didn't step the bottom, but left the cutouts in the spray rails to give the hull the side appearance of the real boat.

 

[T.S.Davis]

Interesting think'n Darin.

So the questions on Mike's and the TFL.......................,

Is the chine just a strake or is it part of the wetted surface? If it's a strake it's not much different than Titan. Breaks in the strakes.

If it's a strake do the trailing edges of the breaks taper or are they squared off? Not an issue for NAMBA as it's not defined but is an issue for IMPBA.

Here's another interesting take. If you look at the bottom of a Revolt from the rear end you'll see that the chine is curved the entire length of the hull. So if the chine is merely a strake the Revolt isn't legal as the "strake/chine" isn't parallel to the keel.

I don't think the chine is a strake BTW.

 

[John Finch]

Christian,

I have used the transom spoiler as well. It keeps the transom from coming up, which keeps the bow from dipping and dunking. It is a good solution as you said.

I would not use a movable weight because the boat will leave the water and crash when you are testing for sure until you have everything worked out. Everything needs to be solid so when the boat crashes it stays in one piece. I have rebuilt 3 boats that crashed before getting the balance perfect. Expect and plan for crashes.

John

 

[Darin Jordan]

Here's another interesting take. If you look at the bottom of a Revolt from the rear end you'll see that the chine is curved the entire length of the hull. So if the chine is merely a strake the Revolt isn't legal as the "strake/chine" isn't parallel to the keel.

I don't think the chine is a strake BTW.

Terry, where in Rule B. MONOPLANE HULL 1. Does it show anything that represents a spray-railed hull shape?? It doesn't.

It lists "Segmented", "Round", "Flat", and "'V'" Shaped.



The spray rails are added to the V-Shape, and can't exceed the dimensional limits of a strake, correct? IF they did, then the hull wouldn't meet the B.4 and B.5 portion of the rule.

The Spray Rails are clearly just another outboard strake (in NAMBA, at least), and, frankly, they do exactly the same thing: redirect water away from the hull bottom and provide a level of lift.

 

[John Finch]

Darin,

I agree with Grim. Each strake on the blue boat is faired into the hull at the beginning and at the end. I don't run NAMBA so I don't know their rules. I have been IMPBA mono Director for about 26 years and I can tell you that there are very good reasons that the IMPBA mono rules are written the way they are. You have to think outside the box a little and then you might see the reasoning. People will take small give me's and turn them into big changes.

 

[Darin Jordan]

Darin,

I agree with Grim. Each strake on the blue boat is faired into the hull at the beginning and at the end. I don't run NAMBA so I don't know their rules. I have been IMPBA mono Director for about 26 years and I can tell you that there are very good reasons that the IMPBA mono rules are written the way they are. You have to think outside the box a little and then you might see the reasoning. People will take small give me's and turn them into big changes.

John,

I see the reasoning very clearly. Strakes are definitely not a mystery to me.

My point on this thread is to determine what is considered legal or not, because there seems to be a lot of question regarding this, in particular surrounding a couple of specific boats. The blue boat I posted above is an example of a boat that is considered legal, but that has strakes that are NOT continuous... they are "broken" in the wetted area. Apparently, in IMPBA, as long as they are faired in front and read, this is legal?

From what I can see, for NAMBA, BOTH boats are legal. I see nothing in the NAMBA rules that would make the Blue boat above, or the TFL/Pro Marine boat illegal.

For IMPBA, it seems that the TFL/Pro Marine boat would be... well, based on what you've said. I don't have my own copy of the IMPBA rules.

 

[John Finch]

I can see that the NAMBA rules are pretty close to the IMPBA rules from the rule book photo you took Darin. By the way, strakes not only spray the water off the hull, they also help to hold a deep vee boat from sliding when negotiating a turn if the boat banks to the inside real strong. The keel is actually more of a turn fin than most modelers realize. Sharpening or rounding the keel in different locations can make the difference between a boat that spins out while cornering and one that tracks well. A warped strake close to the transom can also change how much the boat banks in a cornering manuver. Lots of uses for those pesky little strips. You may know that already but i mentioned that for others reading this.

 

[T.S.Davis]

Did finally get a close up look at the Promarine boat the other day. Doesn't change what any of us thought.

They're beautiful boats.

 

[Darin Jordan]

Did finally get a close up look at the Promarine boat the other day. Doesn't change what any of us thought.

They're beautiful boats.

Refresh my memory... Legal or Not?? (NAMBA or IMPBA??)

 

[John Finch]

Not legal for IMPBA heat racing. Good for offshore racing.

If small steps or breaks are made legal then the next guy builds a boat with the breaks 1 inch wide. Then the next guy pushes them down towards the keel etc. The hull is not one continuous wetted surface. It has breaks. Like Ralf said earlier.........to allow breaks and steps would need a whole new set of guidelines. Then you would have guys who would race their stepped monos in both the mono and hydro classes because they would be legal hydros.

 

[Rokieboater]

interesting conversations here. I guess the real questions is does the strake become part of the wet/running surface? If "yes" then it is not NAMBA legal. IMHO The blue boat should not not be NAMBA legal either. But this is my useless opinion and of course the rules are very vague and written many years ago. Many years ago the argument came up about strakes. One issue was that if the strake did not reach the transom then it was a break in the hull and therefore no longer a mono. Don't remember how that was resolved but here we are again talking about strakes and chines. Of course the next question is, is a chine a strake or not? If its a strake than all is fine, if not then it does not match any of the NAMBA drawings and all monos with the chine are illegal.

In order to run in Electric Offshore the hull must be between 16 & 28 degree V. The ELECTRIC NAMBA Rules allow for the hull to have steps in Offshore.

Unfortunately for NAMBA we do not have a committee or protocol to examine and determine if a boat is legal with in the rules.

Remember this is just one mans opinion and since we have raced these monos for many years they would and should be allowed with out any issues. This is really just a discussion on rule interpretation. NAMBA has many rules that are very difficult to interpret today. They were written and understood by the authors over 40 years ago.

 

[John Finch]

Here is a suggestion for IMPBA folks. When the rules were originally made we raced basic mono and hydro classes and all nitro powered. When the gas classes came along we changed the mono and hydro classes to be rigger, cat, sport hydro, cracker box, and mono. So, in gas racing there is no hydro class. I am surprised no one came up with this suggestion........ If we allowed steps on a gas mono that would not put the boat into the hydro class because there is no hydro class in gas racing. All it takes is for a District Director to make a proposal and let the members vote. The gas classes are classed by boat type, not hull design. The nitro classes would still have to adhere to the mono rules as the nitro classes allow any type hydro to run in the hydro class.

Oh boy did I get the wheels turning!

John Finch

IMPBA National Mono Director

 

[T.S.Davis]

Well...............once upon a time I was TFL's team driver. I was also NAMBA D2 director for stint of two. National FE chairman for a few years too. I was asked about the stepped chine on the TFL Smash Shark a while ago. I always maintained it was a discontinuity in the wetted surface the same way that John saw it. I felt it was therefore not legal for oval heats but was legal for offshore.

Since then I was told that "it's legal" because the Promarine boat was allowed to race mono at the FE nats in Seattle last summer. To my knowledge there is no precedence provision in either rule book. Fought that notion for years. Guys would claim that if allowed one time at one sanctioned race......ever it was hence forth legal. It either complies or it does not. To be disallowed would require a formal protest. This much I do know.

My gut is that it's legal in NAMBA because NAMBA doesn't address the trailing edge of a strake. It can be square and still be legal.

Then in IMPBA it would not be legal as the trailing edge isn't tappered.

I feel like IMPBA got it right too. A sharp trailing edge on a strake could be a sort of step. If you put 10 strakes per side with all of them having a sharp edge you've made a step in effect. I'm not suggesting that's a good idea just that it could be done. IMPBA doesn't actually have offshore rules for electric do they? I'm still studying that book.

I will say though, this is another example of how the rule books differ but shouldn't.

 

[John Finch]

Terry,

I agree with you that if a boat is allowed to run in a race and is illegal.....It does not change the rules to make it legal. In IMPBA there is a process that must be followed to change rules. It starts with an official proposal from a District Director and does not get passed in the end of the process until all model boaters get a vote to pass it or stop it.

John