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[lgosdset]

hi guys,

 i am intrested in  building a deep v powerboat, plan is for it to be about 30" long. what class would this sort of boat fall into, and also what sort of engine would you sujest for a beginner. also, are there any regulations about size, weight, ect ect. I don't think I am going to race my model, its just going to be for pleasure, but i may change my mind later on.

[DickyD]

You need to get in touch with Danny [ omra85 ] he's a member of OMRA and has watched his boat lose races on many occasions, but don't let that put you off, he knows his stuff, just has trouble putting it into practice.

[glennb2006]

hi guys,

 i am intrested in  building a deep v powerboat, plan is for it to be about 30" long. what class would this sort of boat fall into, and also what sort of engine would you sujest for a beginner. also, are there any regulations about size, weight, ect ect. I don't think I am going to race my model, its just going to be for pleasure, but i may change my mind later on.

Hi there,

the class it falls into will generally be based on engine size if you decide to race it, OMRA rules being:

  Class Z 0 - 2.10cc     (0.129 cu in) Non spark ignition

 

Class AA         0 - 3.50cc     (0.21 cu in)   Non spark ignition

 

Class A            3.51 - 7.50cc (0.46 cu in)  Non spark ignition

            (All .46 size engines are approved for this class)

 

Class B            7.51 - 11.0cc (0.67 cu in)  Non spark ignition

 

Class C            11.01 - 50cc  (3.05 cu in)  Non spark ignition

 

Class D            0 - 50cc               (3.05cu in) Spark ignition only

 

 Any mix of fuel is allowed in all classes.

I would imagine the hull maker will recommend engine sizes for their hull, but I would guestimate that for a 30" hull you are going to be at around the 0.46 size, witha good powerful glow motor, or for a lazier motor maybe up to 0.61 size.

Glenn

[ids987]

If you think you might change your mind and want to race later, I would go for something a bit bigger. If you're going for a deep V design, I'm guessing you would race in OMRA - if at all. To give you some idea, the "AA" OMRA boats (for 3.5cc / 0.21 cu in), tend to be at least 1m long these days. One of the most successful AA boats is the Challenger 43 - at 43". I'm not 100% sure about "Z" class, but I don't think they're far behind. Boats for circuit racing (Naviga, oval course) are smaller for the engine size, and faster, but for OMRA, the smaller boats struggle in the rough.
If you want to build a 30" boat for thrashing at the lake, you might just get away with a good .45, but I think it would be well overpowered even for thrashing. If you're going to build it surface drive, I'd tend more towards a sport .21, possibly a "hot" .21 (direct drive), or a .45/.46 sport engine. For submerged drive, probably the "hot" .21 or sport .45.

Just my opinion........

Ian

[ids987]

Looks like 30" is definitely in the ballpark for OMRA Z class. Both sections of Z class (standard and modified), were won last year by the Dateline Cherokee Chief II - at 32". Dateline Renegade (24") and Miami (27") have also been raced in Z.
The smaller the engine though, the more critical everything becomes to get any level of reasonable performance. A .12 engine has very little torque, so the setup of the engine, and the whole boat, needs a lot of attention.

Ian

[ids987]

Looks like 30" is definitely in the ballpark for OMRA Z class. Both sections of Z class (standard and modified), were won last year by the Dateline Cherokee Chief II - at 32". Dateline Renegade (24") and Miami (27") have also been raced in Z.
The smaller the engine though, the more critical everything becomes to get any level of reasonable performance. A .12 engine has very little torque, so the setup of the engine, pipe, driveline, and the whole boat, needs a lot of attention.

Ian

[omra85]

Good advice from Ian. 
The main thing is whether you just want a boat to impress the locals at the lake, in which case get a small boat, big engine, run on your own and turn slowly.
If you want to race (and why not - if I can lose, anyone can) 
then you need a boat that will keep going.  The main difference between Z and the other classes is that they race on different days and at different venues.  You get more short races with Z class, but there are only 2 types (standard and modified).  AA - D has 5 classes but because of the popularity, only uisually run one race per class (normally 30 minutes).
Now that the engine cost limit has been lifted from the Z classes, the cost of the different classes are similar, but getting more expensive the bigger you go.  Some would say that, with the availability of cheap spark ignition engines, this is a cheap way into racing.  I would say that, with the higher cost of tanks, pipes, hulls, and running gear, they are all pretty similar.
Probably the cheapest and easiest would be an 'A' class (7.5cc). The hulls are not too dear and a cheap 'sports' engine will give you a FAIR turn of speed without being too difficult to set up.
Of course, once the bug has bitten, and you start racing properly, you will need to get better equipment to be able to compete at national level - isn't this always the case whatever the hobby.
Have a look at the results on the OMRA website to see what's good (they all require some degree of skill to get the best out of), and take it from there.  If you need more specific information, PM me and I'll give you my phone number for a chat.
Good hunting
Danny