Trim in to get onto plane

[Simon B]

Was reading a book by a distinguished author; he explained a method of getting a powerboat onto the plane by trimming in, lifting the stern and then throttling up whilst trimming out (I assume)

I have never been shown this but the principle seems sound do other more experienced hlems do it this way? If so any more tips or do I need to just go out and do it! Clearly cant apply to much power early on or bow will plough.

[simmons0]

Clearly cant apply to much power early on or bow will plough.

Why should the bow plough?

Most boats can be run all day with the engine trimmed in without problems, if yours is 'ploughing' just by trimming in the engine there must be somthing wrong with the setup.

Or have i got the wrong end of the stick?

[MeMe]

Originally Posted by simmons0

Most boats can be run all day with the engine trimmed in without problems

.........a reduction in speed, poor handling and fuel consumption.

The correct way to get on the plane is to trim the engine in (some people say down) before you hit the juice, then once on the plane trim out (some say up). As you do you will find the revs along with you speed increase slightly.

Judging the right level of trim take time and practice, however a reasonable pretty good rule of thumb is to have the top of the engine parallel with the water.

Triming in or out is also a skill used to adjust handling characteristics in varying sea states.

[simmons0]

.........a reduction in speed, poor handling and fuel consumption.

In our case, a barely noticable change in fuel consumption, about 1.5 knots less speed, at crusising speed, not flat out, and the handling is barely changed.

When running into a sea or blasting through the solent chop you'd take the 1.5 knots less for the smoother ride.

[lc0021]

also - I think you can get a fair guide from the wake (or tail) behind the engine leg - (not to be confused with the wake of the boat... the wake of the leg can be seen as a much smaller vee fanning out from directly behind the engine) as you trim out when you're on the lane you will notice a flattening out of the wake - a rough guide is to trim till the top of the wake flattens off.... (this doesn't sound too intuitive - but if you try it you'll see what I mean)

On my boat - (so I presume on others) you can also tell when you've trimmed out too much from the sound of the engine... hard to describe the chnage in sound - but it's quite noticeable... (and I'm not talking about a load exhaust note.... because then you've trimmed out way too far - and you will be off the plane... http://www.rib.net/forum/newreply.php# )

but ultimately - in my limited experience - it will come by feel (almost second nature...) as you get more familiar with your boat, etc...

[Jimbob]

this comment

"Was reading a book by a distinguished author; he explained a method of getting a powerboat onto the plane by trimming in, lifting the stern and then throttling up whilst trimming out (I assume)"

Is correct

By forcing the bow wave under the boat, then trimming up onto, never really used it due to the power of my boat

[Hightower]

I had to re-learn the trimming of my RIB as I changed the Engine in Feb. I didn't realise there'd be such a difference and with my new setup it's much more sensitive to trim than before.

[Simon B]

This is similar to our situation, we changed engines from a gutsy 140hp 2 stroke to a heavy 100hp 4 stroke. Previously it would plane easily and simply on raw power alone. Less charitable members have suggested that divers are now heavier!