Plane Talking.....

[neilda]

I have all of ten hours clocked up - so there are many mysteries yet to reveal themselves.

One of them would be understanding the feel for being 'on the plane'.

Is it a case of trying to get and keep the boat level (horizontal) when travelling at speed? Or should the bow be slightly raised? How do you know you're actually on the plane - I am experimenting but am not confident I know what I should be feeling/seeing.

All tips gratefully received!

Thanks........

[bedajim]

Originally Posted by neilda

I have all of ten hours clocked up - so there are many mysteries yet to reveal themselves.

One of them would be understanding the feel for being 'on the plane'.

Is it a case of trying to get and keep the boat level (horizontal) when travelling at speed? Or should the bow be slightly raised? How do you know you're actually on the plane - I am experimenting but am not confident I know what I should be feeling/seeing.

All tips gratefully received!

Thanks........

That'll be that Ribeye for you

Did you do the PB 2 or are you learning as you go ?

[Chris]

Neil,

It depends on the set up however most ribs plane between 9 & 11 knots. In a lot of cases the bow will rise slightly as you power off then drop back down as the hull comes onto the plane.

The main thing you need to get the feel for is the trim whilst planing.... as you trim out the steering lightens and the hull starts to feel "looser" on the water, this is because by trimming out the engine you are lifting the front of the boat out of the water until just the rear of the boat is all that is left in the water. This is the most efficient way to run and you will also find the speed increases.

In a following sea it is always wise to be trimmed out as otherwise you risk stuffing the rib into the back of the wave in front as you come down into the troughs.

If you trim the engine back in you will feel the steering start to stiffen up a bit and you will see the bow drop back into the water. This is what you will be looking to do when you want to cut through rougher water and especially a head sea as you will want to keep the bow down as you go over the waves

It's basically a balancing act and judging of the conditions ahead of you so that the boat is in the right trim as you head into the various sea states you will encounter.

[Chris]

... Oh and dont be suprised if you get it wrong and end up with half a ton of water washing around your deck, I think everyone on hear at one point or another will have stuffed (3 weeks ago at Portland Bill was my last one as Matt H's better half will confirm)

[JSP]

Good advice of Chris (even if he did get Matt's wife wet lol)

After you've climbed over the hump start to trim out and as the hull frees it's self your revs will increase.
Good fun init?

[neilda]

Thanks Chris - I think I actually meant trimming.... my terminology is not fully nautical yet!

So ideally you'll run with the bow in quite a high attitude?

Do most boaters run with a lot of trim, only reducing or removing the trim for pootling about? When would you use negative trim? (If there is indeed such a thing?)

There doesn't seem to be much of an explanation in the Yamaha literature about trim - but I assume the midway point on the dial is a neutral (level) trim....

Thanks - sorry for dumbo questions!

[250kts]

"So ideally you'll run with the bow in quite a high attitude?"

No not really. Whilst it will depend on the boat and engine, the average RIB will be running quite level on the plane. As you transit from displacement to planning, you climb over your own bow wave and during this you may find that your bow lifts.
However, once over this, your bow will drop again and your now planning = speed increases rapidly with no more application of additional power.
At this point input babs of trim and listen and feel for increases in rpm/speed, note the trim angle. Keep doing this until either the RIB begins to feel unstable or the prop begins to cavitate, at which point trim the engine back in to the last angle it felt right. You will now have a better feel for what is right for your setup.
Do all this at lowish speed (3000rpm ish) so that if anything happens that you do not like, you still have control.

As said before though, I would strongly recommend doing at least the PWB level 2, with your own RIB, you will learn so much.
Regards
Steve

[Chris]

Neil,

Trim is all about feeling the boat. Each boat is different for example my current Osprey is very well balanced so when trimmed out is not running too nose high the whole boat is effectively out of the water yet still running fairly flat even when it is trimmed out. The down side is that it is slightly easier to stuff this one compared to my last Osprey which had more weight in the back.

However if the Rib is a bit heavy in the arse area it will tend to run a bit nose high when trimmed out which is ok if you are in a following sea but not very comfortable as you head into choppy conditions and can make for quite a dangerous situation if you are in rough head sea conditions as the rib is more inclined to pitch up as you head over the waves.

BTW all of the above is from my own fairly limited experience and there are a lot of other factors that may have an impact on the ribs performance and stability.

Weight distribution plays a big part and a full tank of fuel or 4 adults on board can really affect the performance of the boat and how you trim it.

[jyasaki]

Originally Posted by Chris

Neil,
In a lot of cases the bow will rise slightly as you power off then drop back down as the hull comes onto the plane.

The other thing to look at is the height your feet are over the water surface. Your feet will probably rise by a foot or more as the boat climbs out of the hole. Though admittedly, it can be tough to tell as your speed increases.

jky

[neilda]

Useful stuff - many thanks....

I have done a day with an instructor, we covered how to trim but I'm afraid a combination of excitement and too much information.... luckily I have remembered the more essential stuff.