Advice on inconveniently located frame

[alan_fincher]

Is this a steel cabined boat? If so I would just cut both of these plates out completely. The cabin should be more than adequate to hold the sides in place.

 

Generally I would agree with you David, but not on this. I don't think many steel boat cabins are built in a way that is designed to stop the hull spreading, and some might even do the opposite, (a cabin that isn't particularly well braced will be trying to spread the hull, if anything).

 

I hope the OP will get the answer they want, but I would leave these alone until it is confirmed they have nothing to do with the structural integrity of the hull. Adding gussets not unlike these is one way of preventing a hull from spreading, and it is possible (but not certain!) that this may be their intended purpose.

[FadeToScarlet]

 

I've had to do a very basic hand drawn (and definitely not to scale!!) plan to explain. As you can see the starboard brace would be in the walkway, the frame/brace on the port side isn't a problem as it can be hidden in a cupboard.

 

I have a C shaped kitchen in my boat.

 

You will have about 6' to play with once lined out, a bit less above the gunwales.

 

That's enough for one row of standard units along the wall, and one 500mm wide unit or fridge at each end to make the arms of the C.

 

This does give two "dead" corners which are hard to access- good places for a calorifier, or for sliding shelves.

 

Edit- I have a small, 400mm depth cabinet- originally a wall cabinet- opposite the open side of the C, which would hide the brace in your layout.

Edited December 6, 2016 by FadeToScarlet

[FadeToScarlet]

 

Ignore the washing up!

 

Cooker closest to camera, so you can stand at it and talk to people in the living room.

 

Don't forget the height of the taps, if you're putting the sink near the wall- they will prevent you putting the cabinets under the gunwales, unless you have a shallow sink.

[mayalld]

I have a C shaped kitchen in my boat.

 

You will have about 6' to play with once lined out, a bit less above the gunwales.

 

That's enough for one row of standard units along the wall, and one 500mm wide unit or fridge at each end to make the arms of the C.

 

This does give two "dead" corners which are hard to access- good places for a calorifier, or for sliding shelves.

 

Edit- I have a small, 400mm depth cabinet- originally a wall cabinet- opposite the open side of the C, which would hide the brace in your layout.

 

Looking at the dead corners, the one closest to the bathroom would clearly be a candidate for a calorifier, but the one in the living room can probably open into the living area as a cupboard.

[Kate89]

Response from David Piper:

 

'Katie

I would strongly recommend that you try to work around this knee

You could move this knee around 60cm forward or back if it helps but if you remove it you will find that the hull side will flex

Regards'

 

Looks like it will have to stay. Eurgh I dislike it even more now it's called a knee.

[alan_fincher]

Response from David Piper:

 

'Katie

I would strongly recommend that you try to work around this knee

You could move this knee around 60cm forward or back if it helps but if you remove it you will find that the hull side will flex

Regards'

 

A timely reminder that not all advice given on this forum is good advice!

[RLWP]

Looks like it will have to stay. Eurgh I dislike it even more now it's called a knee.

 

Why? Boats and ships have had knees for centuries

 

Richard

[Tony Brooks]

My six pennyworth. The horizontal stringers are far lighter than those on my Colecraft so I can see some strengthening is required, especially in the case of a full side impact from another boat. I also think, although its nothing to do with this thread, that the stringers are not ideal in that they will trap any water from leaking windows etc, but that is another matter.

 

The catwalk/gunwale fold forms a strong resistance to side flex at the top and the floor bearers do the same at the bottom. What do the welder types and proper engineers on here think about welding some vertical box sections from the floor bearer to the gunwale? Notice I indicated more than one. I think maybe three spread along the length of exposed hull.

 

There are two pipes that would get in the way. The lower one can easily be hidden by boxing along the floor. The upper one may need a more creative approach but it all depends what it is used for. Maybe hidden by shallow wall cupboards hung under the gunwale.

 

I also think that no engineering expertise has gone into specifying this knee. From what ii can remember form college there is a lot of metal there that is not contributing to structural strength so looks like a "do it the easy way " job to me.

 

Have I heard this hull fabricator being recommended as one of the good ones?

[Alan de Enfield]

 

Why? Boats and ships have had knees for centuries

 

Richard

 

But, to be fair, they are only vestigial, remaining from the dim & distant past before they took to the water.

[RLWP]

 

But, to be fair, they are only vestigial, remaining from the dim & distant past before they took to the water.

 

[mayalld]

 

Have I heard this hull fabricator being recommended as one of the good ones?

 

David Piper was certainly one of the leading builders of that time (1969-2001, for most of that time based at Red Bull), and His sons are still building boats.

 

David Piper boats (particularly the early ones may have features, such as the knees, that modern builders have found more elegant solutions to, but compared to other boats of their time, they were certainly good boats, and seem to have lasted better than some other builders.

 

The classic Piper boat is distinctive, and whilst the design now looks a little dated, it is less dated than other boats of that time, with unusual hopper windows (full height opening hopper in the central portion, and fixed panes at the side), and usually small brass portholes at the rear.

 

Piper owners tend to advertise the fact, and a piper boat is as likely to be signwritten as "Red Bull Basin" as a Braidbar boat is to have "Registered at Higher Poynton"

[Kate89]

Why? Boats and ships have had knees for centuries

 

Richard

Just a joke... I didn't know boats had knees

 

I dislike it mainly because it's interfering with our kitchen plans.

[bizzard]

Those are really gusset plates. Knees are generally curved wooden corner braces on wooden boats. A giant G clamp could be lowered by crane over the centre portion of the boat and tightened up at the gunnels to stop the sides bulging. It might not pass through narrow locks afterwards though. To stop narrowing or shrinkage of the hull a constant internal pressure could be maintained by the the use of an air compressor, running constantly with all hull openings bunged up to maintain the pressure.

[hounddog]

There are some frames vaguely like that in one of my boats. They were put there to hold the sides in place after chaining them in the get the width down to under 7ft.

Maybe your boat used to have middle age spread.

 

Just as an aside: do they work?

[bizzard]

Gusset plates are generally of a triangular shape and give tremendous strength and rigidity if of the correct proportions for the job.

Drawbacks= Steel gussets can rust and corrode, condense moisture and is cold to the touch.

Knees being wooden are usually made from naturally curved bits of branches of trees, often oak. Drawbacks= wooden knees can attract woodworm, dry rot, wet rot, are warmer to the touch but can suffer, bleeding, cartilage trouble and arthritis also Knee knock if placed too close together, Pinocchio suffered badly with knocking of the knees.

Edited December 6, 2016 by bizzard

[blackrose]

A timely reminder that not all advice given on this forum is good advice!

Very true. I see some complete nonsense written on this forum sometimes, and occasionally add my own contribution of balderdash.

[Flyboy]

If I were you I would not be removing these braces. Looking at the pictures there is a lack of vertical side stiffeners which would normally be welded to the base cross members giving a degree of bracing (like a knee) . If you take the braces out you would then be relying on the gunnel to stiffen the sides.

[Kate89]

Those are really gusset plates. Knees are generally curved wooden corner braces on wooden boats. A giant G clamp could be lowered by crane over the centre portion of the boat and tightened up at the gunnels to stop the sides bulging. It might not pass through narrow locks afterwards though. To stop narrowing or shrinkage of the hull a constant internal pressure could be maintained by the the use of an air compressor, running constantly with all hull openings bunged up to maintain the pressure.

That all seems a bit extreme given that there's no problem currently apart from it interfering with our proposed kitchen layout... we might just have to make do

I emailed the David Piper guy back and questioned the need for 'knees' and if we could 'trim' them in some way, and this is the response I got:

 

'Kate

It is there to stiffen the hull side

I would rec leaving it in and working around it.

Other builders do not fit these knees and seem to get away with it

You may find that the hull side could flex in and out in different temperatures especially when the sun is low. Fitting a few vertical angle frame to replace this knee would be inline with what other builders would do.

Regards'

 

So maybe we could trim it back but weld a few more down that side of the boat to make up for it??

Edited December 6, 2016 by Kate89

[Bee]

Well that is a surprise. I've never seen anything like that in a narrowboat whether old or new. Bigger barges had or have that sort of triangle but coming down from under the side deck or coaming to the frames, kept the bottom clear for coal /stone /grain, you could bang your head on them but they are out of the way. Think I'd still cut them out and put in a few small triangles.

[WotEver]

So maybe we could trim it back but weld a few more down that side of the boat to make up for it??

 

That is exactly what TonyB proposed several posts back. Basically, replace the one huge fillet with several box sections welded to the sides and base.

[bizzard]

That all seems a bit extreme given that there's no problem currently apart from it interfering with our proposed kitchen layout... we might just have to make do

I emailed the David Piper guy back and questioned the need for 'knees' and if we could 'trim' them in some way, and this is the response I got:

 

'Kate

It is there to stiffen the hull side

I would rec leaving it in and working around it.

Other builders do not fit these knees and seem to get away with it

You may find that the hull side could flex in and out in different temperatures especially when the sun is low. Fitting a few vertical angle frame to replace this knee would be inline with what other builders would do.

Regards'

 

So maybe we could trim it back but weld a few more down that side of the boat to make up for it??

Not all that extreme really. The enormous great G clamp is easily fabricated by a competent steel manipulator and air compressors come cheap these days. Aldi do a beauty for under a hundred pounds. The normous G clamp could be substituted with a great long steel hauser or big fat chain chain encircling the whole boat midships like a ladies girdle, both ends being fastened together on the roof with a bottle screw for fine adjustment. However the pressurized cabin air compressor would need to be retained.

Edited December 6, 2016 by bizzard

[Kate89]

 

That is exactly what TonyB proposed several posts back. Basically, replace the one huge fillet with several box sections welded to the sides and base.

Yes sorry I had noticed that excellent suggestion. If we can get a welder in soonish that definitely is an option.

[bizzard]

Without nice stiff hull sides the opening and closing of transverse internal doors can be seriously effected by changes in temperature. Keep the gusset plates.

[Tony Brooks]

Just to be clear my suggestion was not based on any calculations and it would involve a lot of fairly accurate cutting to fit the box section behind the stringer upright. Some of the welding would probably be a bit difficult as well.

 

I think each complete upright would need three lengths cut and it may be advisable to weld a horizontal "load spreader" section under the gunwale as well. As belt and braces once the box section is welded in a long strip of steel could be welded over the front face of the box section and new upright strengtheners. This woudl not have much side impact strength but would tie the various pieces together.

 

There is still that pipe to consider, I think cutting a hole through the box section would weaken it too much.

 

I had hoped that those with better skills and experience in this area would comment and expand on my idea (as to why it would or would not be a good idea).

Edited December 6, 2016 by Tony Brooks

[BWM]

Well that is a surprise. I've never seen anything like that in a narrowboat whether old or new. Bigger barges had or have that sort of triangle but coming down from under the side deck or coaming to the frames, kept the bottom clear for coal /stone /grain, you could bang your head on them but they are out of the way. Think I'd still cut them out and put in a few small triangles.

Knees are common on commercial narrow boats, necessary in part due to the open construction. Picture shows one having the metal replaced due to corrosion behind it. It doesn't take up as much space as the ones on the o/p's boat though.