Hi , new to boats and looking to build an MHZ Cougar wharf boat 51" ie 70" fountain

**NativePaul** · 01-09-2017, 05:53 PM

Where do you live? Unfortunately this forum only allows 2 letter locations I don't recognise QC. In USA where most of the members here live their organisations insurance will only cover them up to 10s, In most of Europe including England where I live it is up to 14s, other areas may vary. It may be possible to get third party insurance cover just for yourself, or you may have a private lake and not need it, but it is an issue worth considering.

Do you want to race or think you may want to race in the future? If so there may be rules to follow that will help you narrow down your setup choices.

What are your goals for performance and runtime?

Could you link to the hulls you are thinking of please, you mention 51" and 70" but there is a big difference between the 2, and the MHZ Cougar and Mystic are both about 55".

Even 55" boats and 400A ESCs are out of my experiance zone so I cant give you any specific advice, but I can give you some generalisations that are true for all boats, or all electrics.

I would use the highest voltage you can get insured on, that are race legal if you are interested in racing, or you are comfortable with handling in a wet environment, and that your ESC will take, although it is good to leave some headroom on the ESC and not run it at the maximum limits for either voltage or current. The higher the voltage you use the less current you need for a given power so the ESC, wires and connectors will run cooler.

I think what you have heard of is prop cavitation, all fast boats will have it to some extent coming out of the hole, it does reduce prop efficiency and thrust at low speed. Bigger diameter props with lower pitches will reduce cavitation, and smaller props with higher pitches will increase cavitation. heavier boats have more drag and more inertia, so will have more cavitation for a given prop. There is a compromise to be had between low speed acceleration and high speeds, generally fast boat will accept some cavitation reducing low speed acceleration when the boat is in displacement mode in favour of better acceleration at high speeds. The compromise can goo to far in that you need a certain amount of thrust to climb out of the hole and get up on plane, or you won't ever get to those higher speeds.

Given props of the same pitch ratio (1.4 is very popular for fast boats) KV matters in that for a given power with low KV you can spin a bigger diameter prop slower with high KV you can spin a smaller prop faster, the Low KV spinning a bigger prop will cavitate less and accelerate better at low speed and may be as fast, but will have more torque roll and paddle wheel effects.

**Doby** · 01-09-2017, 09:05 PM

QC = Quebec..Canada

**devin120** · 01-10-2017, 03:05 AM

Yeh.. No rules about cells or anything.

I'm from quebec canada.

No plans on racing. I want to go for all out speed runs on a pretty smooth lake. Thus the 16 s. Runtime, 5 mins? Seems fair... Not bashing too hard...

Thanks so much for the info. Thats alot of the info i needed.

I shall update on any progress :)

Hi , new to boats and looking to build an MHZ Cougar wharf boat 51" ie 70" fountain

Hi , new to boats and looking to build an MHZ Cougar wharf boat 51" ie 70" fountain

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