Aerotec 380: speed

[piotr]

Hi,

Took the Aerotec out for the second time last sunday and I experimented a bit with the engine trim (tilt). I have an older model Mecury 15hp 2 smoke (1995) and i measured a topspeed of 30kmh (not miles or knots), with me (90kg) and my 9 year old (30kg) and some gear onboard. (conditions wind 4bft, a little choppy) I didnt notice excessive splash. What do the experienced Aerotec sibbers think ? Is this a reasonable speed or should I get a bit more out of the 15hp ?

Thanks for your advice !

[Nick Hearne]

Just over 16knots sounds about right, flat calm and loose some weight and you will get 18 knots may be 20 with wind and tide going down hill

[piotr]

Another question: what kind of fuelconsumption should i expect ?

[Max...]

Haven't a clue what 30 km ph is but with mine loaded with about 150kg total we're usually at 17 kts WOT rarely (tide assisted) touching 18 in a typical UK sea (ie not glass). A little lighter load and dead calm we might touch 19 now and again but 15/16 is a nice cruise with our rig.

My consumption seems to be all over the place depending on usage (river pootling/coastal cruising/wave jumping but rarely better than 2.5 nm per litre, more typical is closer to 2 nm per litre which I tend to stick to for calculating fuel needed.

I was looking at maybe trying a different prop on the 380/Merc 15, if anyone has changed the standard prop please comment on the below:

http://www.rib.net/forum/f50/y-class...tml#post683234

[Neuner]

Piotr;

Kindof in the same mindset as you right now with my setup but instead of looking at your speed, I'm looking for longevity of the engine and minimize wear and tear. Either way, the basic evaluation are relatively similar.

We have a 4.2m with a 20hp 4s and with my wife and three kids + gear. At first we were at 16 mph or 25 km h with the standard prop that comes with the engine which is 10 pitch but are now at around 18mph or 29 kmh after changing to a 9 pitch. Both in similar calm conditions. After observing the splashing of the engine and the WOT rpm I believe we still have work to do which may or may not add to the top speed.

I think you need to get a tach to obtain the rpm at WOT and post your engine's best operating rpm range and other details about your setup so the others would be able to direct you as to if your setup can be improved upon.