Excel Volaire 390 - First Impressions

[Brerabit]

I will Chris - but not tonight.
Six hours back from Scotland and then I hit a 90 min tailback 10 mins for home.
Need a dram or three and a rest before I get my head around posting video's,
I've had more than enough new experiences for one week.

[chris moody]

When testing my new cupped prop for the first time it was ventilating like crazy and would not even plane. I returned to the slip to swap my prop back to the old uncupped one, only to discover the real reason for the issue was I’d left my wheels down. Very embarrassing

[Brerabit]

Thanks for that Chris, I don’t feel quite so inept now I know the experts can also get it wrong from time to time.

I need to swat up on props and learn what effect size, pitch and cupping have because although I’m not keen to spend more money and am more than happy with what I can get out of my boat I suspect that the prop is the reason it reaches max revs/speed so quickly. To my untrained senses it seems as though I’m hitting a limit, before it’s worked hard enough. Whether that limiter is in the motor or is just the load on the prop balanced against the power of the engine I don’t know but something is instinctively telling me that there’s more to give as it doesn’t seem to be trying very hard.

[chris moody]

The first thing you need to do is buy a tinytach and fit it to your engine. You can get them for under £10 off eBay if you are not in a hurry (delivered from China), or a search on this forum will find a different model that’s around £30, is more robust, and will get delivered sooner. Then use the tinytach to see what engine revolutions you get with the throttle wide open (WOT) and the boat travelling flat out. Knowing the speed at the same time from a gps or phone app would be also useful.

Then we need the size of the existing prop (stamped on it), the gearbox ratio (in the engine manual) and the maximum rev range at WOT (also in the manual). From all that info we can work out if you have the correct propeller, and if not calculate what different sized prop would work better.

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Thanks for that Chris, I don’t feel quite so inept now I know the experts can also get it wrong from time to time.

I need to swat up on props and learn what effect size, pitch and cupping have because although I’m not keen to spend more money and am more than happy with what I can get out of my boat I suspect that the prop is the reason it reaches max revs/speed so quickly. To my untrained senses it seems as though I’m hitting a limit, before it’s worked hard enough. Whether that limiter is in the motor or is just the load on the prop balanced against the power of the engine I don’t know but something is instinctively telling me that there’s more to give as it doesn’t seem to be trying very hard.

[Bigsofty]

The first thing you need to do is buy a tinytach and fit it to your engine. You can get them for under £10 off eBay if you are not in a hurry (delivered from China), or a search on this forum will find a different model that’s around £30, is more robust, and will get delivered sooner. Then use the tinytach to see what engine revolutions you get with the throttle wide open (WOT) and the boat travelling flat out. Knowing the speed at the same time from a gps or phone app would be also useful.

Then we need the size of the existing prop (stamped on it), the gearbox ratio (in the engine manual) and the maximum rev range at WOT (also in the manual). From all that info we can work out if you have the correct propeller, and if not calculate what different sized prop would work better.

Glad I read this. I just assumed that the 'standard' prop would be perfect match but obviously not all boats are the same so maybe its a 'one size fits all' situation. I'll follow that advice and get myself a tacho. Any excuse to buy a new gadget

@Brerabit Lovely photo . Looking forward to seeing the video. What stunning scenery

[chris moody]

I purchased this tinytach

https://www.ebay.co.uk/itm/Waterproof-D ... 520841735

I believe other members on here use this one as well

https://www.ebay.co.uk/itm/Trail-Tech-7 ... 2922850228

[Brerabit]

I have two of these and they have never given me any trouble

Engine Hour Meter Inductive...

[chris moody]

How waterproof are they ?

I’m not expecting the £6 one to last very long.

I have two of these and they have never given me any trouble

Engine Hour Meter Inductive...

[Brerabit]

That's great and a relatively straightforward process to find out if it's right or could be improved.
...and at less than 30 quid for a rev counter it must be one of the rare items that's cheaper for a boat than a car.

[ChrisParish]

How waterproof are they ?

I’m not expecting the £6 one to last very long.

Dunno - I haven’t killed it yet and it has got very wet.