Weird engine behaviour

[jimh]

this is my diagnosis too. Can be overcome with careful throttle control - lots of frequent adjusment to keep her on the plane. You can normally hear and feel when the boat slows and the revs drop, and similarly when she races away and the revs rise, these need to be counteracted with more / less throttle.

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[Doffy]

Try going slighty across the waves to give you a longer run at the flatter water.


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[FlowerPower]

Hi,

I've found that in following seas I need to "work" the throttle fairly assertively to prevent the effect you are describing. What I do is to use almost full throttle as I climb up the back of the wave, then ease off substantially as I surf down the face of the wave: that way you can keep an (almost) constant speed.

If you leave the throttle at a constant setting, what happens is that as you climb the wave, you slow down, the revs drop, and below about 2500rpms the Turbo isn't much use, so the revs drop more, down to 2000rpms or so. Finally the compressor (supercharger) thinks it would be a good idea to kick in, big shove of torque, lots of acceleration, too fast !, you back off the throttle, the revs drop... rinse and repeat.

dave.

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[Matthewb]

Dave,
Maybe if you're down on yours in the next couple of weeks I can coax you into coming out with me for 30 mins so I can show you what happens and try out your remedy. I'll make sure I've got some of your favourite tipple onboard !!!

Matt

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[h4nym]

Blimey - u sea folks! Into ur hard work aren't u!

When I've been out on the big water, if it gets lumpy I slow it down. Much easier to go thru the water than to try and beat it!

H

<hr width=100% size=1>http://www.ElectronicWorkplace.com>Work</A> balance? :-)

[BrendanS]

Even slowing down doesn't mean you don't have to work the throttle. Some boats respond better, some less.

After being out in conditions which meant some seriously steep high waves, some book learnt techniques came into their own, alongside learning as I went.

When waves are taller than your boat, you zig zag. Throw helm over left as you go down, as you reach bottom, throw helm over right, power on as you go up. Power off as you go over the top and.....all this at displacement speed. I probably never went over 5 knts. Front on was horrrible.

It all made sense after a while,and was quite easy going. This approach assumes you have plenty of fuel, though slow displacement speeds are usually quite fuel efficient and you really had to be able to power up the wave, or it would be quite dangerous

The upside is that you don't get any slamming or damage. Saily types move at this sort of speed most of the time, and you get there eventually. Much easier to go with the flow, and just take what is thrown at you , rather than try to force the boat to go faster than feels comfortable

What I hate is slamming conditions, where the waves are so short and steep that you're going to hit hard. In some ways, big swell is easier to cope with

<hr width=100% size=1>Err, let me know if Depsol enters the forum, I'll go and hide