New RIB design? - Page 3

Scott2 · 16 March 2005, 11:09

John. I do realise the hull shapes, spray rails, keel shape and arrangement etc are different per type of boat and the angles of bow/stern etc also.

But what I was pointing out was that you could go on for years with photos saying hey! this looks like...

without a picture from exactly the same angles either of the boats can look slightly different enough to be the same or not the same.

I dont have a RIB and the only ones I have been on are RNLI Atlantic 75s & a RNLI Valiant DR490, but I've worked on Avon Seariders. appart from that its SIBs & Hardboats

MarkWildey · 16 March 2005, 11:09

Quote:

Originally Posted by John Kennett

I quite often find myself looking at things like spray rails and wonder

John

You need to get out more!!

Mark

John Kennett · 16 March 2005, 11:13

Quote:

Originally Posted by MarkWildey

You need to get out more!!

I did say "quite" often.

But you're probably right

John

King_C · 16 March 2005, 11:22

How do reverse chimes work?

Ive been in a gemini that had them and it seemed to grip more in the corners than my avon that tends 2 slide slightly.

Jono · 16 March 2005, 11:30

Quote:

Originally Posted by John Kennett

Although superficially similar (reverse chine and one spray rail) I think that the differences would be very apparent if the two boats were put side by side.....

Feckin' Hell. JK.... you wanna join the Diplomatic Corps you do...

What Ol' Lanky meant was.... they look nuffin' like.... and your's needs a good wash.....

John Kennett · 16 March 2005, 12:09

Quote:

Originally Posted by King_C

How do reverse chimes work?

First of all, it's chiNe not chiMe

They divert the water downwards and away from the boat, increasing lift and stability. It's quite a common feature on planing boats, but the size and angle of the chine varies. The bigger the chine, and the greater the reverse angle, the greater the effect.

The Gemini, as you noticed, has a very pronounced reverse chine. It hardly banks at all in corners, which can make holding on a bit of a challenge!

John

King_C · 16 March 2005, 12:19

Yeh sorry that was a typo.

Does a bigger more reversed chine tend to mean it will slam more in big seas? As its a flatter edge to the water?

John Kennett · 16 March 2005, 12:24

It will tend to, although you're not likely to notice it unless the chines are much bigger than normal.

As a rule the more flat (or reverse angled) surface there is on a hull, whether it is in spray rails or chine, the more lift you'll get but the harder the ride will be.

John

Nick Hearne · 16 March 2005, 12:27

Quote:

Originally Posted by Jono

Feckin' Hell. JK.... you wanna join the Diplomatic Corps you do...

What Ol' Lanky meant was.... they look nuffin' like.... and your's needs a good wash.....

I only said it looked similar not the same & given the different angle of the photo I still think it dose! But I do not think for a moment it is a copy of a Osprey
You saying my boat needs a wash?

jackeen · 16 March 2005, 12:30

Quote:

Originally Posted by John Kennett

The Gemini, as you noticed, has a very pronounced reverse chine.
John

JK

I suppose that is the 6 mtr version only ??

paul

King_C · 16 March 2005, 12:37

I dont know which it was i went in as it was a few years ago at the boat show but i did love the way it cornered!

John Kennett · 16 March 2005, 12:41

It was definitely the 6m I was thinking of -- don't know about the others though.

John

Nick Hearne · 16 March 2005, 12:41

Dose this one show a better similarity?

John Kennett · 16 March 2005, 12:42

That's spooky! I think you might be on to something there . . .

Don't give up the day job!

John

Jono · 16 March 2005, 12:43

Quote:

Originally Posted by Nick Hearne

Dose this one show a better similarity?

...No... but it looks cleaner.....

King_C · 16 March 2005, 12:43

I could be wrong but everybody is showing pics of the transom (i think possibly because there arent others of the leeway hull- as far as ive seen) but cant the hull be completely different from there on?

Matt · 16 March 2005, 14:01

Thought I showed a picture of the bow, and a phantom 18 bow also.

Quote:

Originally Posted by King_C

I could be wrong but everybody is showing pics of the transom (i think possibly because there arent others of the leeway hull- as far as ive seen) but cant the hull be completely different from there on?

King_C · 16 March 2005, 14:06

Ah ok sorry didnt see that. My browser doesnt let all the pics show so i hav2 move my mouse around posts to see when it goes to the little hand.

Musta missed those ones.

Adam Younger · 16 March 2005, 15:56

Quote:

Originally Posted by John Kennett

How hulls are designed, and why design decisions are made, is something that doesn't often get a lot of coverage. I quite often find myself looking at things like spray rails and wonder whether they are a conscious design decision, for a methodically thought out reason, or whether they have just been out in because the designer likes the look of them.

John

This really sums up why the whole case of splashing is so offensive to Designers.

I work as a designer, mainly on planing hulls and yes every spray rail - every feature, every dimension is thought about and is there for a reason.

Someone who has splashed a hull has not gone through that process or is not capable of going through that process so can hardly start to call such a craft their own design.

Adam

codprawn · 16 March 2005, 16:25

How many variables can you have on a deep V hull of a certain length and beam?

Surely it is a case of someone trying to reinvent the wheel?

I would have thought that one reason for so many similar hulls is down to modern CAD programs - in a similar way so many modern cars look the same as they have been styled in the wind tunnel.