Reply
 
Thread Tools Search this Thread
 
Old 27 February 2007, 04:11   #11
Member
 
Pete7's Avatar
 
Country: UK - England
Town: Gosport
Boat name: April Lass
Make: Moody 31
Length: 9m +
Join Date: Aug 2001
Posts: 4,850
Manos, you started this thread with quite a good couple of posts and then lost it with a quick swipe at Scorpion

Quote:
Originally Posted by Manos View Post
Convex type hulls (like the Scorpions) allow for such modifications. And although the hulls perform well in rough seaw, the drawback is that they propose a lot in normal sea conditions.
Really I am assuming you mean "porpoise"

I think congratulations are in order then, because it probably takes quite a bit to make a Scorpion hull handle badly. You would need excessive trim and a badly balanced boat to do it, for example lots of weight in the nose. Since your profile doesn't say Scorpion then it must have been a friends boat, if so were you the excessive weight in the nose? Suggest you advise your friend to do a boat handling course and learn to drive a rib.

Quote:
However, other types of hulls IMHO do not allow such modifications and they feel very uncomfortable in most of normal sea conditions.
Well, you are entitled to your opinion, but I think if you asked a dozen Ribcraft owners they would say there ribs handle sea conditions very well.

Quote:
If this is my thoughts are correct for example, a 6 meter boat that comes out from the same mold of say a a 10 mtr boat may not have as good sea keeping capability as a similar boat that came out of a custom made mold.
Possibly, it would be very nice if every manufacturer could design and build different hulls for every size of boat he wanted to sell. Back in the real world costs and time dictate otherwise. If taking a 6.5m rib from a 7m mould produces a hull that handles well in the mind of the manufacturer why not take it to the market place and see if the market agrees with them. A while back you complained about costs of manufacturing in the UK, would you be willing to pay extra for a manufacturer to develop each hull on its own? if so then can I suggest you buy a Scorpion, you never know you might start a new trend and style of driving a rib with porpoising catching on throughout the med

Pete
__________________

__________________
.
Ribnet is best viewed on a computer of some sort
Pete7 is offline   Reply With Quote
Old 27 February 2007, 08:13   #12
Member
 
Country: Greece
Town: Gloucetsreshire
Boat name: GATO DI MARE
Make: MAR.CO
Length: 9m +
Engine: Yamaha 200Vmax
MMSI: 235027678
Join Date: Sep 2002
Posts: 3,339
Send a message via MSN to Manos Send a message via Yahoo to Manos Send a message via Skype™ to Manos
Hi Pete,

The Scorpion hull (Bertram design) was an example. There also may be other hulls that have the same/similar aggressive concave (egg shaped) hull design. But that make came first in my head.

Porpoising in calm seas is an effect of this type of hulls what ever you do to them. Everyone knows that. We are making the same discussion again and it may be boring for others

I'm sure that you will agree though that costs in the UK are higher than in Europe in general (not only boat costs) and IMHO it will be reasonable to say that products manufactured in this country are more expensive than products manufactured in Spain, Portugal, Italy, Greece, South Africa, South America, Canada etc. That will apply to boats too I think? I believe is a natural effect and there's nothing wrong with that.

I can't see your point
__________________

Manos is offline   Reply With Quote
Old 27 February 2007, 08:36   #13
Member
 
gtflash's Avatar
 
Country: UK - England
Town: southampton
Boat name: TOP CAT 2
Make: Scorpion 8.1
Length: 8m +
Engine: 250hp HO
Join Date: Aug 2003
Posts: 1,316
ignoring the left to right hull shapes, how do they allow for the varying deadrise across the entire length of several length of boats out of same mould?
__________________
gtflash is offline   Reply With Quote
Old 27 February 2007, 17:48   #14
Member
 
Richard B's Avatar
 
Country: UK - England
Town: Devon
Boat name: White Ice
Make: Ranieri
Length: 5m +
Engine: Suzuki 115hp
Join Date: Jul 2002
Posts: 5,015
Quote:
Originally Posted by Manos View Post
The Scorpion hull (Bertram design) was an example.
Do you mean the Scorpion speedboat or the Scorpion RIB?

The Scorpion RIB is a David Marsh design.
Richard B is offline   Reply With Quote
Old 27 February 2007, 18:49   #15
Member
 
Bigmuz7's Avatar
 
Country: UK - Scotland
Town: Glasgow
Boat name: stramash
Make: Tornado
Length: 5m +
Engine: Etec 90
Join Date: Feb 2006
Posts: 5,068
I think Manos, to address your original question, I'd have to say I've owned 3 boats from the same manufacturer of 3 different lengths. Not all were from the same hull designer, but all were the same width. Unless outright speed is an issue, the characteristics will be largely similar, save for bow angle etc, but for me the difference from a 6.5 to an 8.5 m boat was bigger than any other change I've made. It maybe down to my local coastal prevailing conditions, but I feel I can travel safely so much further in a 8.5m hull than both my previous 5.8 or 6.5 models. Sea keeping made a big advance for me with those extra 2 metres
__________________
Bigmuz7 is offline   Reply With Quote
Old 28 February 2007, 18:51   #16
Member
 
gtflash's Avatar
 
Country: UK - England
Town: southampton
Boat name: TOP CAT 2
Make: Scorpion 8.1
Length: 8m +
Engine: 250hp HO
Join Date: Aug 2003
Posts: 1,316
Quote:
Originally Posted by gtflash View Post
ignoring the left to right hull shapes, how do they allow for the varying deadrise across the entire length of several length of boats out of same mould?

no one know?
__________________
gtflash is offline   Reply With Quote
Old 01 March 2007, 02:41   #17
Member
 
Richard B's Avatar
 
Country: UK - England
Town: Devon
Boat name: White Ice
Make: Ranieri
Length: 5m +
Engine: Suzuki 115hp
Join Date: Jul 2002
Posts: 5,015
Even on a warped V hull, the varying deadrise is negligible at the rear, and most will be parallel in the last couple of metres so it's irrelevant.
Richard B is offline   Reply With Quote
Old 01 March 2007, 03:16   #18
Member
 
Country: Greece
Town: Gloucetsreshire
Boat name: GATO DI MARE
Make: MAR.CO
Length: 9m +
Engine: Yamaha 200Vmax
MMSI: 235027678
Join Date: Sep 2002
Posts: 3,339
Send a message via MSN to Manos Send a message via Yahoo to Manos Send a message via Skype™ to Manos
So what you say Richard is that what ever the V in the transom is the same mold can be used to build a 6, 7, 8 and 9 mtr even 12 meter boat or whatever length one requires?

But wouldn't be that the length, draft and beam of the boat must be proportionate in order to have good sea keeping characteristics???
Manos is offline   Reply With Quote
Old 02 March 2007, 19:13   #19
Member
 
Richard B's Avatar
 
Country: UK - England
Town: Devon
Boat name: White Ice
Make: Ranieri
Length: 5m +
Engine: Suzuki 115hp
Join Date: Jul 2002
Posts: 5,015
No Manos, you're stretching the point, as well as the hull! The range 6-12m is clearly not going to produce a great range of hulls from the same mould. And a 6m RIB needs different hull characteristics from a 10m+ RIB, which may need a greater internal beam for the installation of twin inboard engines. However, if you had a mould that you could use for hulls in the 7-9m range, you would probably find that it worked very nicely.
Richard B is offline   Reply With Quote
Old 03 March 2007, 04:28   #20
Member
 
Country: Greece
Town: Gloucetsreshire
Boat name: GATO DI MARE
Make: MAR.CO
Length: 9m +
Engine: Yamaha 200Vmax
MMSI: 235027678
Join Date: Sep 2002
Posts: 3,339
Send a message via MSN to Manos Send a message via Yahoo to Manos Send a message via Skype™ to Manos
Ok ....
__________________

Manos is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 18:07.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.