[Batboat48]

Hi everyone, i have a 28cc weedwacker engine which i am converting for use with my 48inch batboat. I am trying to build the exhanust system at the moment and have found a java applet on Modelpowerboat.com where i have to imput certain data such as velocity of rotation, exhaust port angle etc, this is all fine, i have worked them out using various methods but i am stuck on finding out the Exhaust temperature. Is there any way (besides buying a really expensive thermometer and specialist probe) of finding this out.
Also, ive ordered a tachometer to find out my Rpm and was wondering, when i put a prop onto it and run it, how much am i likely to lose...ish....i.e 10percent, 20percent....
Thanks for any help
batboat48

[Ron Olson]

One slippage factor that I've seen used says 15% but that can vary according to hull type and weight. Any lifting hull, even deep-vee's will have less drag the faster they go as there will be less hull in the water.

[HendricX]

Save yourself the trouble making your own pipe , most internet pipe-designers are crap.

For 84$ you can buy a "china-pipe" on eBay , they are not bad at all.