Boating Jargon
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lawrence567

Original Poster:

7,507 posts

219 months

Thursday 23rd June 2011
quotequote all
Hi,

Could someone please explain to me, what "plaining" means in boat terms?
In the context of, i was reading some literature about an inflatable & it said "to prevent plaining", it was referring to the motor size / shape of the boat.

Any ideas? As i'm not very boat minded.

Cheers

Tyre Smoke

23,018 posts

290 months

Thursday 23rd June 2011
quotequote all
It's planing.

It means surfing on the waves. Planing is highly desirable in a sailing dinghy as it increases your speed across the water.

In a motor boat it's not so desirable as it causes the propeller to 'skid' in the water and lose grip and therefore drive.

In very simplistic terms it's like a surfer riding his board on a wave, or driving your car with a strong tail wind.

Simpo Two

92,646 posts

294 months

Thursday 23rd June 2011
quotequote all
Displacement hulls sit 'in' the water (displace the weight of the craft). Speed is limited because the boat physically has to shove water out of the way to make progress.

Planing hulls are designed to skim over the surface, thereby vastly reducing drag and increasing speed.


lawrence567

Original Poster:

7,507 posts

219 months

Thursday 23rd June 2011
quotequote all
Ok,

So in inflatable terms it means that if you have say a too poweful outboard it'll not be efficent?

Flintstone

8,644 posts

276 months

Thursday 23rd June 2011
quotequote all
Tyre Smoke said:
In very simplistic terms it's like...driving your car with a strong tail wind.
Sure about that? wink

NDA

25,527 posts

254 months

Thursday 23rd June 2011
quotequote all
lawrence567 said:
Ok,

So in inflatable terms it means that if you have say a too poweful outboard it'll not be efficent?
Not sure I understand that question.

All RIBs (for example) plane, they are said to 'get up on the plane'. So going slowly they will plough through the water and then, with a bit of throttle rise up out of it and ride on the surface.

Big yachts and what-not, do not plane. They plough through the sea. As above, they have displacement hulls.

If you have an underpowered motor, you might not have enough power to get up on the plane. Your inflatable will therefore not be efficient. I have a mate with a little pilot boat and this would not get up on the plane until about 21knots - somewhere near the maximum performance of his engine. Inefficient.

Too powerful and you'll plane easily - however you might start to chine walk, which can be extremely dangerous.

anonymous-user

83 months

Thursday 23rd June 2011
quotequote all
If you have a powerful inflatable (RIB) then planing is what you get at high speed where the boat lifts out of the water more and thus you have less resistance. It;s great fun and meant to happen but the boat handling can get rather "twitchy" as I know very well smile

Tyre Smoke

23,018 posts

290 months

Thursday 23rd June 2011
quotequote all
Flintstone said:
Tyre Smoke said:
In very simplistic terms it's like...driving your car with a strong tail wind.
Sure about that? wink
Yup, it's like getting a 'push'.

Tyre Smoke

23,018 posts

290 months

Thursday 23rd June 2011
quotequote all
NDA said:
Big yachts and what-not, do not plane. They plough through the sea. As above, they have displacement hulls.
You sure....



Okay so it's a huge dinghy, but I wouldn't want to! yikes

lawrence567

Original Poster:

7,507 posts

219 months

Thursday 23rd June 2011
quotequote all
I understand now, i just re-read & it said, designed to optimise planing, i'm a spaz.
However i do have another question.
If an inflatable has a power / HP rating.
Say the rating is 10HP & you put a 15HP outboard on the back of it, obvioulsy your operating outside of the manufacturers recommendations, voiding warranty etc & the extra weight of the engine, but what is the effects of this, i presume front end lifting up & flipping?

NDA

25,527 posts

254 months

Thursday 23rd June 2011
quotequote all
Tyre Smoke said:
NDA said:
Big yachts and what-not, do not plane. They plough through the sea. As above, they have displacement hulls.
You sure....
I knew when I was writing that that there are dozens of exceptions - however I was trying to be roughly right so that the OP would have a vague understanding. Big motor launches get on the plane too - despite being displacement hulls.

smile

Tyre Smoke

23,018 posts

290 months

Thursday 23rd June 2011
quotequote all
lawrence567 said:
I understand now, i just re-read & it said, designed to optimise planing, i'm a spaz.
However i do have another question.
If an inflatable has a power / HP rating.
Say the rating is 10HP & you put a 15HP outboard on the back of it, obvioulsy your operating outside of the manufacturers recommendations, voiding warranty etc & the extra weight of the engine, but what is the effects of this, i presume front end lifting up & flipping?
Potentially, yes. But in reality there comes a point where the maximum speed of the hull through the water is reached. Bigger engine doesn't always mean more speed.

A 75hp outboard on your 6' tender dinghy would just sink it, but bolt it to your 12' RIB and you'd have quite a handful after about 20 knots - if you got that far before it started to chine steer.

lawrence567

Original Poster:

7,507 posts

219 months

Thursday 23rd June 2011
quotequote all
Ah i don't have anything that size, i've just bought a small dingy.
About 2.8m or so in length.
I'm not saying i'm going to, but if it's rated to say 3HP & i stuck a 5Hp on it would it do much to it?

Tyre Smoke

23,018 posts

290 months

Thursday 23rd June 2011
quotequote all
lawrence567 said:
Ah i don't have anything that size, i've just bought a small dingy.
About 2.8m or so in length.
I'm not saying i'm going to, but if it's rated to say 3HP & i stuck a 5Hp on it would it do much to it?
No, that would be fine, even up to 20hp I would think you'll be okay. But that would be like putting a big V8 in a Micra!

lawrence567

Original Poster:

7,507 posts

219 months

Thursday 23rd June 2011
quotequote all
Ah i see, no probs in that case.
I bought a small intex seahawk 2 inflatable & stuck a little British Seagull on the back.
Now i did'nt expect it to be fast, but it barely pushed me & one of my friends along in it, to the point where unless the sea was like a mirror it would probably be unsafe, hence why i've upgraded to a "proper" inflatable & getting a bigger outboard for cove exploring etc.

Simpo Two

92,646 posts

294 months

Thursday 23rd June 2011
quotequote all
The power and the prop and the hull design have to be matched.

NDA

25,527 posts

254 months

Thursday 23rd June 2011
quotequote all
Simpo Two said:
The power and the prop and the hull design have to be matched.
And the pilot.

(Says the man who managed to fall out of his boat at high speed recently) smile

Tyre Smoke

23,018 posts

290 months

Thursday 23rd June 2011
quotequote all
Simpo Two said:
The power and the prop and the hull design have to be matched.
Yes, but on a 10 foot dinghy with a 5hp outboard, we're not exactly talking offshore powerboat racing are we?

hehe

He'll be fine.

lawrence567

Original Poster:

7,507 posts

219 months

Thursday 23rd June 2011
quotequote all
Tyre Smoke said:
Yes, but on a 10 foot dinghy with a 5hp outboard, we're not exactly talking offshore powerboat racing are we?

hehe

He'll be fine.
Powerboats you say... scratchchin


Caulkhead

4,938 posts

186 months

Thursday 23rd June 2011
quotequote all
Planing:



Not planing: