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Old 03 October 2016, 12:15   #31
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Originally Posted by macandrc View Post
The white paint makes it very difficult to see the key features, the Durabuild primer is a dark grey which will hopefully show the hull in its full glory. As you mention the steps on the Interceptors are different to traditional stepped hulls, the hull line is continuous with the steps interrupting in a delta format. You could call it a warped shape, it certainly was a pain getting the materials to contort and bend to the shape! I have attached an image which might help out.

Colin
Thanks for the picture, think i more or less get the shape now. Will be interesting to see the ready product at some stage!
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Old 04 October 2016, 13:54   #32
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Here are a couple of pics for those following progress, the photos are after the first couple of coats of the Durabuild primer. We ended up putting 3 thick coats and started sanding it all back to a shine today ready for machine polishing.

Hopefully the attached pics show the shape a bit clearer than the previous pics when the hull was painted white with the sealer.

As always we welcome your comments/questions

Colin
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Old 04 October 2016, 14:06   #33
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very interesting and thanks for uploading.

may i ask what is point of the tubes if they are not ever in water?

or what are the pros and cons in your view of having the tubes in the water?

cheers
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Old 04 October 2016, 15:57   #34
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Originally Posted by dubrus View Post
very interesting and thanks for uploading.

may i ask what is point of the tubes if they are not ever in water?

or what are the pros and cons in your view of having the tubes in the water?

cheers
They may not be in the water at Standstill...on Calm water...there's the clue!
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Old 05 October 2016, 03:47   #35
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Tubes Pros & Cons?

Quote:
Originally Posted by dubrus View Post
very interesting and thanks for uploading.
may i ask what is point of the tubes if they are not ever in water?
or what are the pros and cons in your view of having the tubes in the water?
cheers
Thanks for the question. It is one I have been asked many times, particularly in the early years of designing and building my designs. Before specialising in ribs I was a more 'traditional' designer/builder working with anything from sailing craft to work and fishing boats. Moving into ribs in the 80s it always struck me as odd that considering an inflatable was then being given a solid (usually grp) hull to enhance performance it seemed to me strange that others were at the same time taking away a couple of big advantages a solid hull offered, further reserves of bouyancy and stability. Some even flooded their hulls to gain stability when at rest by resting on the tubes.

Previous to ribs well designed boats had adequate stability and bouyancy by way of their hulls only and I reasoned this should remain the case with ribs. Hence my designs have always had hulls that were in themselves stable and bouyant without relying on any tubes at all if it came to it, say through mishap or damage to a tube. We proved this by launching an early Carson 6 metre and drove it around Liverpool docks BEFORE the tubes were fitted. This feature can be especially seen in my larger ribs as posted here.

I was often criticised for this approach in the early days and attempts were even made to bar Carsons from racing and some other events. Needless to say these attempts failed and nowadays it is a very common design feature.

Other advantages of keeping the tubes clear of the water are that they are saved from the worst effects of wave flotsam impact and weed groath accumulated when kept afloat. This is particularly important with ribs that like all Carsons over 5.5 metres can achieve speeds of at least 50 knots. I'm sure you'll appreciate the forces are considerable and even the strongest fabrics will eventually fail.

Soft cushioning fendering is another reason for having tubes and a big plus for boats that are used for boarding other craft. When inflatable conventional tubes are used they also save weight and with larger ribs may be deflated when towing on the road, particularly useful with bigger boats when their inflated beams exceed legal limits. Even our 750, 850, 900 and 950 models can all be legally towed when deflated. They also fit into containers for shipping and for the military be put inside transport aircraft.

The main down sides of tubes are 1 their cost and 2 their relative vulnerability compared to other types of craft's sides (grp, alloy, steel and wood, etc).
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Old 05 October 2016, 04:01   #36
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Not sure what happened but not all my reply came up on my previous post:

Huge reserves of bouyancy and stability are of course other big pluses for having tubes. Very useful when you may be having a bad day!

And apologies for typing errors: groath should read growth
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Old 07 October 2016, 15:48   #37
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Hi barry. What is the purpose of the flat keel line? Does it work like a small planing pad?

Thank you for your time to explain things to everyone. It's so nice to have someone with so much knowledge, who shares it.
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Old 11 October 2016, 15:33   #38
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Hi barry. What is the purpose of the flat keel line? Does it work like a small planing pad?

Thank you for your time to explain things to everyone. It's so nice to have someone with so much knowledge, who shares it.
Thanks for the question gtflash. To a small extent the flat keel line does work like a planing pad as any flat surface area would. However this is not its prime purpose. We offer the option to fit a stainless steel keelband to allow beaching or grounding and some hull protection when transported on trailers with keel rollers. Many military users specify this option.

The wide keel form also allows us to build more strength in this crucial area and spread impact loadings over a wider area. Eliminating the planing pad also offers a softer re-entry when the hull jumps clear of the water. Kinder on the boat and the crew. These Interceptors while eminently suitable as medium speed workboats are also designed for very fast open water operations (as the name implies).

Many of my other designs do have planing pads (as well as the same flat keel lines as here) to assist in getting a heavily loaded boat onto the plane and staying there at relatively low speeds. However with these Interceptor model which have a very deep V of 24 degrees the planing pad is replaced with broad spray rails, 4 in the after part of the hull and typical of all my designs there are wider 'gullwing' spray rails or chines running the full length of the hull. In addition to assisting getting on the plane and achieving more speed and economy for a given horsepower they also add enormous stability both at rest and speed and assist in throwing spray out and clear to produce a drier than normal ride.

I hope this answers your question and thanks again for asking.
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