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Old 19 May 2008, 18:48   #11
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Stainless legs need to be designed very carefully, in my opinion they were the only design fault on the smaller Flatacraft range.
Its very difficult to stop small amounts of movement around the bolts becoming large ones over time as they allow the transom to flex.

I'd have thought the original style knees bonded in over the stringers and attached through into the ply with Stainless steel screws before being over-bonded in place would be a much more suitable repair.

Who is doing the work? and what sort of guarantee have you got from them or Northcraft now that the design differs from its original spec?

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Old 19 May 2008, 22:54   #12
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I would have been inclined to drill some large holes through the transom and into the knees and insert 1" wooden dowels liberally coated with epoxy.
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Old 20 May 2008, 03:36   #13
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what sort of guarantee have you got from them or Northcraft now that the design differs from its original spec?
This is the question I was asking in my original post. How did Northcraft clasify the hull to Cat B, and after this work, how do I retain it, does the hull have to be retested ?

It was my understanding that the hull was a heavier design with extra stringers or ribs heavier lay up etc, amongst other things, to meet cat B spec.

Ok so its two questions. What I'm getting at with the second one, is,.. shouldnt it have been less likely for a cat B hull to fail in this manner ? As I have photos inside the hull from the stern and can see no evidence of extra stiffening.
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Old 20 May 2008, 06:07   #14
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After more research today, the best info I can find is on this link here

http://www.ceproof.com/recreational_...htm#Categories

And a chat with one of the chaps there, suggested there is no obligation for the category approval to be 'maintained' as it is a snapshot of the crafts manufacture which allows it to be sold throughout Europe, and it is not a requirement or standard which requires testing. Seems a bid odd why they bother CE marking them with different categories then ? I cant find any info other than hull length which designates what a cetegory is.
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Old 20 May 2008, 06:33   #15
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As a manufacturer I won't comment on the hull directly, but as far as the CE system goes there is nothing that actually says a cat b boat has to be stronger than a cat c - if they are both designed for a 300 they should be as good as each other. The whole CE thing is actually misleading in my opinion as the general buying public can be misled into thinking that a cat b boat is better than a cat c - in fact it will need to get through much more testing (quite expensive), but to pass cat c we have to provide layup schedules, fill it full of water and drain it out within a time frame, perform handling tests and it has to be generally up to the job.

In short a CE category b boat isn't necessarily any better - it just passed some tests a cat c boat didn't take!

In addition I think the CE rating of this boat has nothing to do with the issues that you're having.
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Old 20 May 2008, 07:38   #16
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i think the whole system should be scrapped - my 9m and my little Quicksilver are both rated C - I wonder which I would prefer to be on in the rough..............
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Old 20 May 2008, 10:54   #17
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I noticed a blue Northcraft at Rothsay the other weekend with a Verado on it. It had some rather substantial stainless knees/supports fitted to the transom. Might be worth trying to get a hold of the owner and see if he has had the same problems.
HTH
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Old 21 May 2008, 14:24   #18
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Quote:
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Its very difficult to stop small amounts of movement around the bolts becoming large ones over time as they allow the transom to flex.
This was certainly a concern of mine, IMO some sort of small hatch beside the brackets is the way to go, since a service inspection of the fixing bolts is a must, at regular intervals, I didn't consider the bolt grade (x4 per bracket) being good enough not to loosen slightly during use, the repairer simply used nylock nuts on standard metric threaded bolts, personally, I'd prefer double lock nuts and some type of marine grade stud lock or lok-tite, also a plate on the inside of the through bolt on the stringer instead of simply washers on the nut side, so as to spread the load, as the stringer is essentially compressible, and hauling up a bolt and nut will never stay solid due to that compression, then I thought maybe not, nylock might suffice, as due to the compression, a nip up now and again might be neccessary, although with a spreader plate, hopefully this would be minimised, but as always Gents, your thought are welcome.

Personally I'm surprised & disapointed the manufacturer has acted in the way they have since like it or lump it.. the plate says 300HP and its only done 80 hours for Gods sake. Its a cop out for them to try and walk away from this, which is what they have done.

If this boat was in commercial hands, I'm sure the story would be different !!
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Old 22 May 2008, 01:23   #19
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This was certainly a concern of mine, IMO some sort of small hatch beside the brackets is the way to go, since a service inspection of the fixing bolts is a must, at regular intervals, I didn't consider the bolt grade (x4 per bracket) being good enough not to loosen slightly during use, the repairer simply used nylock nuts on standard metric threaded bolts, personally, I'd prefer double lock nuts and some type of marine grade stud lock or lok-tite, also a plate on the inside of the through bolt on the stringer instead of simply washers on the nut side, so as to spread the load, as the stringer is essentially compressible, and hauling up a bolt and nut will never stay solid due to that compression, then I thought maybe not, nylock might suffice, as due to the compression, a nip up now and again might be neccessary, although with a spreader plate, hopefully this would be minimised, but as always Gents, your thought are welcome.
The under floor part of the bracket could of been twice the length with a few more bolts and it is begging to have a plate fixed to the inside to spread the load. If its not sealed why not ask them to do it and double nut them its your boat !

Will the transom have a large plate on the outside with the new brackets bolted all the way through ?

James
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Old 24 May 2008, 03:56   #20
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Will the transom have a large plate on the outside with the new brackets bolted all the way through ?

James
Yes it will have, the transom its self is 3 inches thick at the top now, so its pretty heavy duty.
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