UIM rules - please help

[Mike_G]

Hi guys.
As you know couple months ago I have bought Ring 20C called Buzzin Hornet
After many weeks of rebuilding I have broke bottom hitting in something that was laying in the water. Hole in the bottom is quite big and I don't think that fixing it is a good idea.
So I had to make choice, because importing brand new hull (I don't want second hand anymore) from UK or belgium is quite expensive I've decided to make model, moulds and made my own boat. Hope to sell some of them to earn money for racing

It will be about 6.6 - 6.7 metre monohull to fit 3C and 3C EPA racing class
I have all CE regulations (translated in to Polish language) how to make boat that I will be able to sell but I want to make boat that will meet UIM rules cause I want to race in it and maybe someone will race in it too
Unfortunetly I have UIM rules only in English and I don't understend everything so if you could help me with it I would be very gratefull

First thing is rule 501.11 6th section

Should the trailing edge of the planning surface of hull or sponson terminate with an angle greater than 15degres measured between the keel and outer chine in plan view (bird eye view), such excess shall not be included in the measured lenght..

I don't understend a word from it
Can someone explain it to me what is it all about?? Or maybe draw me a picture....

Next thing rule 502.03 section 3
Can someone explain to me what is this transverse section? Whati is it all about??

Next thing
If I don't use canopy do I need to fallow 508 rules? Besides 508.60??
Do I need to use strobo light when boat is without canopy??

Ok back to rule 508.60
Reinforced Water Deflector underdeck and over deck
What is underdeck water deflector??

And more:
Rule 730.1
What is this CUBE?? Cause I don't understand it
Bouyancy. It is said that for 3C EPA boat GRP bouyancy is 370 litres
Is it all?? Cause boat have to weight like 695kg min. Or is it additional bouyancy??

And what about the wieght?? For 3C EPA it is 695kg min. I understand it it hull and engine. What anout fuel? What if hull, engine and fuel will weight 695kg and after race it will weight less cause fuel will be burned??

Ok thing this is all for now??
Thanks for help
MIKE

P.S. I didn't know in what section put this tread technical or muster so I've post it in general

[gazza]

This is a huge task!
To design a boat,
To build a boat.
and be competitive and win,
I take it you have laminating experience?
Adam on here may be a good start to go over your drawings, to see what will or wont work in reality,he can also do your drawings, he did a set for me a few years a go for a 30ft one off.

[verytricky]

Cube rule is to control to some extent the dimensions of the boat.

You have to imagine a cube ( square or rectangle ) the size they state. Then you have to be able to fit this imaginary 'cube' inside of your boat.

So you can not build a 40 foot boat 2 feet wide and one foot high, as the cube will not 'fit' inside this boat shape.

[Mike_G]

Yes I do have laminating experience, my father has. He designed and build cool 21 ft cabin cruiser many years ago. Make couple copies and sold moulds.
I hope this experience will be enough

I have some ideas how to make this boat and how to build bottom to make it go fast. Hope it will work. Still I'm thinking if I will make something as fast as mannerfelts bat boats. Cause I belive they are main boats in 3C classes HOW FAST ARE THEY WITH XR2 ??
My friend here in Poland is making me drawnings right now so they will be ready soon I hope.

Thanks for explaining me the Cube Rule

Waiting for other answers

Thanks again
MIKE

[verytricky]

The Bat Boats are really good for the rough sort of weather you get in the UK. They tend to perform as well in the rough as they do in the calm. Other boats perform differently in rough or calm conditions. So on a calm day you are likely to get beaten by a fast boat, but on a rough day you will be doing the same speeds as in the calm.

One word of caution. Occe has copyright on his hull designs. He has before and will definately take legal action against anyone who *copies* his hulls. So if you make a copy or a 'splash', expect a big legal bill and a payment to Occe. However, if you design a hull, based on or in the spirit of a Bat Boat, but do not copy one, then that is legal. So to design your boat, using your interpretation of his ideas is legal, but if it is a copy of his hull, you will pay!



I had hopped someone else would answer this, but.....

Bouyancy: I *think* this is the bouyancy of the boat when filled with water and placed into the sea. I *THINK*. So although a floating boat made of iron will float when it is not filled with water, it has no Bouyancy when filled with water. We have to carry bags of air inside the boat to make up the limit on this rule. So it appears for every litre of trapped air in a bag, you get 1kg of bouyancy, so if your hull weighs x kilograms and displaces Y amount of water you can calculate its bouyancy to be negative ( sinks ) or positive ( floats) and then add air bags to reach the minimum amount.


Under the deck deflector - is just that - to deflect water away from crew if the hul opened up ( as in a dive by the boat ) to stop the force of this water hitting the crew. It is under the deck, not under the hull.

You do not need a strobe light.


502.3 section 3:
If you cut your boat into slices, like a loaf of bread, these slices are 'transverse sections'. Each bottom (hull) bit *must* have the deepest part of the hull in the center, and they *must* slope upto the sides of the boat. ( so you can not have a double hull or a completely 'flat' hull ) The exceptions to this are listed and are not really 'exceptions' - they are limits on steps and chines.


501.11:
Look at the boat from the top. ( plan view ) Most boats heve a sharp pointy bit that is in the frount, and a blunt square bit at the back. The back is where you mount the engines. The back is also where the running surface of the hull ends, and this point is used for measuring the length of the hull. Sometimes the 'back of the boat is not a straight line, but is rounded or pointy. Almost like someone stuck on a triangle onto the back of the running surface. If this 'triangle' that you stuck on has a sharp angle of more than 15 degrees, then this surface is to be ignored in the measurement of the boat.


730.1 -> 731:
For class 3c the boat must weigh the minimum at the END of the race, including any fuel and safely equipment. There are different rules for 3B, 3D, 3S etc, but you are asking only of 3C

[Mike_G]

Don't worry verytricky I will not make a copy or splash of any mannerfelts or other hull. It will be normal monohull boat.

I just want to check if I understand everything properly

Underdeck waterdeflector (first pic ) - so I shall make some kind of wall under the hull ( red line) right?? And over deck water deflector are blue lines??

Look at second pic, that is (more or less) how my bottom should look like
If I understand everything correct I can make KEEL PAD on the bottom as long as it is not flat but have positive angle ( like 10 degree)
Second thing what are those spray deflectors?? Blue lines??
According to the rules I can make spray deflector (in example last one ) with negative angle but less than 20 degree (red lines)
Spray deflector can not be wider than 8% of the total bottom widht (third pic). Right??

What about steps?? I can only make step in place not exceding 25% lenght of the boat from the back (last pic). Right??

[Mike_G]

Am I understending everything correct??
Please help

[Jon Fuller]

Originally Posted by Mike_G

What about steps?? I can only make step in place not exceding 25% lenght of the boat from the back (last pic). Right??

That doesn't sound right
maybe the step's dimension fore & aft from leading edge (normaly at keel) to outer edge at chine?? I don't know this, just guessing really.

excuse the poor drawing. (obviously NOT to scale)

[Jon Fuller]

I know the tinterera (or however it's spelt) was almost deemed to be a multi hull, because the rear pad was concave. and the lowest point of the boat (keel) must run for more than a certain percentage of the length. hence the Ocke's have that wee double concave pad with the centre bit very slightly lower than the outer bit, thus maintsaining the centreline as the lowest point all the way along it's length

[Mike_G]

Cool

Thanks for help

MIKE