K4 plus & Atlantis KR7 (some ? about this Rib)

joakimhansson · 25 June 2006, 21:47

http://www.atlantisribs.com/ (yes, i did a search first)

I just got information on this rib in my mailbox. For me it looks VERY good, do you have any comments on it?

The price is 13995£ for S, and 19995£ for RS. Ok, much money but in Revenger country. It has stepped hull and some race history on it, but I saw deadrise 19 degrees and transom rise 13. Is that normal? Doesn´t most of the rib have 24 degrees deadrise?

Is everything built in UK?

In my brochure the length is 7,12 beam 2,46 and weight 800kg (S or RS?)
Revenger 23/715 has length 7,15 beam 2,46 and weight 740 kg.

Speed with opti 150 is 64-66 mph! Sounds possible?

Ezgoing · 25 June 2006, 21:57

deadrise seems very shallow. This means the boat has a hull which is flatter than many .

A flatter hull means it will plane easier, can be driven by less horsepwer. However I am under the impression that it will not be as good a seaboat as some of the deeper v hulls.

best of luck.

daveh · 25 June 2006, 22:02

You are right; the boat was launched at Ribex and is proving to be a huge success. It has a unique hull design which is stepped and is incredibly efficient. It is absolutely true that this boat will do 66 with a 150hp on the back. I have been out on the boat and it is quite fantastic, the demo boat had a 125 on the back just to prove it! Every part of the boat is custom built in Southampton; you can choose seating and console layout, tube colour, upholstery and so forth. This boat really does show up some of the big players. The people who build the boats are so passionate and helpful.
I really recommend you book a demo, the ride is unbeatable - to be honest it's far better than some of the big players which require twice the horsepower to drive them.

I found out today that the boat is category B (most are CE cat C) which is unusual and certainly disproves any question marks as to its sea keeping abilities.

I shall be placing an order early next year

joakimhansson · 25 June 2006, 22:12

daveh, how much did they pay you

No, it´s sounds/looks like a very nice rib.

My biggest ? is still the deadrise, I will contact them tomorrow and see if 19 degrees is right and if the have some pics on the hull to send me. But they race with the hull if it´s the same???

daveh · 25 June 2006, 22:16

Quote:

Originally Posted by joakimhansson

daveh, how much did they pay you

No, it´s sounds/looks like a very nice rib.

My biggest ? is still the deadrise, I will contact them tomorrow and see if 19 degrees is right and if the have some pics on the hull to send me. But they race with the hull if it´s the same???

Yeah yeah its the same hull, there's magazine reviews of the boat coming 1st in every race but one!! - that was when the engine blew up!

Hightower · 25 June 2006, 22:34

I've seen the Ads on Boats and Outboards.

I too would be interested in any opinions about the build and design.

Looks quite an attractive price for a self build project of a RIB of this size.

joakimhansson · 25 June 2006, 22:38

With a Mercury ?

joakimhansson · 25 June 2006, 22:46

Yes, but the price for a complete boat is 13995 or 19995 (S/RS). If I remember it was some ad at boatsandoutboards with less than that! The RS is with everything you need.

I have some question about the engine size but then I will send them a question at a packageprice with boat, engine and trailer. Then it´s more easy to compare to the other.

Downhilldai · 25 June 2006, 23:25

Quote:

Originally Posted by daveh

You are right; the boat was launched at Ribex and is proving to be a huge success. It has a unique hull design which is stepped and is incredibly efficient. It is absolutely true that this boat will do 66 with a 150hp on the back. I have been out on the boat and it is quite fantastic, the demo boat had a 125 on the back just to prove it! .....

What was proven by the demo boat having a 125 on the back?

slimtim · 26 June 2006, 07:46

You need to speak to adam younger on here, he designed it. I haven't ever been in one but have seen adam's own hull zooming along and it just seems to "float" across the water! It has tapered steps to improve cornering. It would be high on my list if I could afford one!

Cookee · 26 June 2006, 08:06

Quote:

Originally Posted by daveh

I found out today that the boat is category B (most are CE cat C) which is unusual and certainly disproves any question marks as to its sea keeping abilities.

It might be worth noting that the CE marking is basically a self certifying system, and the category a boat is rated to isn't actually an indication of a boats seaworthiness - having said that Adam is a well respected designer and I'm sure this hull is very seaworthy! Have a look at some of the Italian boats - it's amazing what will qualify as a B cat boat!

John Kennett · 26 June 2006, 09:10

Quote:

Originally Posted by joakimhansson

[url="http://www.atlantisribs.com/"]
I just got information on this rib in my mailbox. For me it looks VERY good, do you have any comments on it?

I believe that it is the same as the prototype that Adam Younger was demonstrating last year.

If so, it's definitely worth a look. The hull gives good speed with modest power, and I was impressed with the ride.

John

joakimhansson · 26 June 2006, 09:40

OK, need to work little for some money, to buy one

Adam Younger · 26 June 2006, 10:58

Quote:

Originally Posted by John Kennett

I believe that it is the same as the prototype that Adam Younger was demonstrating last year.

If so, it's definitely worth a look. The hull gives good speed with modest power, and I was impressed with the ride.

John

Indeed it is - we made the decison to move away from boat building - mainly as the design business was / is going really well and that was our speciality. We then sold the moulds and are very happy to see Atlantis developing the whole concept and doing a really good job at 'productionising' the boat.

I have kept my own boat - which was the prototype / demo boat - as I have had so much fun from it and does everything I want it to. At the moment I'm re-rigging it with an E-Tec and also incorporating a series of updates.

Adam

Adam Younger · 26 June 2006, 11:09

With regards to the deadrise angle - it is a complicated hull - and one we are particuarly proud to have developed. Whilst it is stepped there is also a lot more going into the design than that!

We have designed stepped hulls for many years - but I firmly believe that as a design office we have developed these hull forms for production boats further than others. Most notably our hulls have tapered steps - which stilll gives some of the performance gains - but also most importantly gives a great balance between performance and handling. Certainly if we develop a design for racing only, then the steps are different.

We certainly find that as the craft (as stepped hulls generally do) rides a lot more level the bow sectrions work far more effectively and do there job. Thus it is possible to utilise slightly lower deadrise angles aft and thus aid efficiency again.

Deadrise at Transom
The initial section is of a pad effect type and as such is low deadrise. The main planing section to the main chine is then at 21 deg. We then incorporate an outer chine with the deadrise angle between the two chines being 40 deg. Overall there is a mean deadrise angle of 22 deg. The main panel also has some camber added to it - thus actually giving it variable deadrise.

The inner section aids efficiency, main section gives the majority of lift and determines the ride of the craft - and the outer section really comes into play in rough conditions, turning - whilst adding extra beam to the craft.

In bow sections the deadrise goes up to a maximum of 48 deg - mean. By this stage the pad has been faired out and the main planing section and outer section merge into one as the two surfaces become one.

Adam

joakimhansson · 26 June 2006, 12:55

Thanks,

Very good answer. Thank you

The Atlantis RIB is even more interesting now. Thanks,

joakimhansson · 26 June 2006, 12:59

Quote:

Originally Posted by Adam Younger

At the moment I'm re-rigging it with an E-Tec and also incorporating a series of updates.

Adam

What size on the e-tec? Tell me about handling with the e-tec?

I have suzuki 175 4-stroke or e-tec 150-200 in my plans.

Adam Younger · 26 June 2006, 13:27

Quote:

Originally Posted by joakimhansson

What size on the e-tec? Tell me about handling with the e-tec?

I have suzuki 175 4-stroke or e-tec 150-200 in my plans.

I'm putting a 150 HO E-Tec on - probably another two to three weeks until it's on the water as work is really busy at the moment. Planning to use the boat for general cruising and sports but also may take the rear seat out and do the odd race with her. Maybe a round of the French championships next year.

I'm sure the E-Tec or Suzuki 175 would be great. Had a 140 Suzuki on my boat till recently and it has been excellent.

joakimhansson · 26 June 2006, 13:32

Quote:

Originally Posted by Adam Younger

I'm putting a 150 HO E-Tec on - probably another two to three weeks until it's on the water as work is really busy at the moment. Planning to use the boat for general cruising and sports but also may take the rear seat out and do the odd race with her. Maybe a round of the French championships next year.

I'm sure the E-Tec or Suzuki 175 would be great. Had a 140 Suzuki on my boat till recently and it has been excellent.

Do you have any pic´s on your boat? How fast was it with the suzi 140? Please tell us more about the boat when you have it in water with the new e-tec on

Looking forward to hear/see.

Adam Younger · 26 June 2006, 13:41

A photo from a RIB get-together early last year.

Best speed we saw with the 140 was 54mph - although there would have been a bit more there with a touch more pitch on the prop as we were reaching the rev limiter. Very noticeable that the engine was still 'loosening-up' and giving more power even after 50+ hours of use.

Will post some more details when we get to try her with the E-Tec.