Help Design my Boat.....please!

rustybarge

rustybarge

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Hi All,
Just got delivery of a new aluminium frame for my 25' Cat.

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Here's my woeful effort at designing a roof and superstructure with 'Paint' Software on an iPad. As you can see the frame is very high in comparison to the length of the boat. Result very boxy.:(

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Any idea's?

Please feel free too draw your own design on top of these photo's.

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Here's what it looks like with the roof in the low position, much better balance between the hull size and the roof.....:)
But no standing headroom.:mad:
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rb,

I'm afraid not much to suggest!
I mean you probably need standing height, no brainer, height is set!
width, not much you can do.
only thing remaining is slope of front screen and number of supports on the elevations.
Since the ali frame has a number of supports, dividing by 2 as it seems you've done is a sensible option (if not the only option!)

So, what exactly can we suggest?

cheers

V.

PS. quite liked daughter's sketch :D
 
Thanks vas,

My only weapon seems to be stripes and colour!!!

Have you noticed how different colours make a car look a totally different shape?
 
true,

use colour in order to make something look smaller or bigger. So, if you want to have a sleeker look, you'd use tinted windows (I guess you are going to have glazing all around, no?) and paint the pillars and roof in a dark colour.
If you feel it's still too high, do a dark strip on the top of the hull (like your blue but probably not blue)

Cat is fairly high, innit?
What materials are you thinking for skinning this frame?

V.
 
vas said:
true,

use colour in order to make something look smaller or bigger. So, if you want to have a sleeker look, you'd use tinted windows (I guess you are going to have glazing all around, no?) and paint the pillars and roof in a dark colour.
If you feel it's still too high, do a dark strip on the top of the hull (like your blue but probably not blue)

Cat is fairly high, innit?
What materials are you thinking for skinning this frame?

V.
Click to expand...


Tinted windows.....

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I went into B&Q today to see how strong plywood is. We stood on a 9 mm sheet supported at 3' centers.....nasty cracking noise. Weight 12 kg.

Also considered 1.5 aluminium sheet, but the fabricator said there's no way it would support a person standing on it. Also 12 kg. he suggested using 1 mm ally and just standing directly on the frame, like a aeroplane wing's 'no step'.

Total allowed weight is 300 kg for roof and superstructure.....that's not a lot.
 
Just a few rambling thoughts :

Re disguising the hull freeboard, you could paint the hull a darker colour, while keeping a fairly thick (100 mm?) white boot-top stripe, and a contrasting antifouling colour.
Or just have a couple of (say) blue boot-top stripes, with white stripes between them and the antifouling / waterline.
To compliment the boot-top stripes the side profile of the deck moulding and the small cabin forward could be in the same colour.
Rather like the blue stripes in your first post, but going down to the hull / deck joint.
I think the blue stripes in way of the gunwhale in post 6 are way too deep.

Re the framework, I would have chosen 1.5" / 38 mm diameter circular tubing rather than square, at least for the pillars.
And have them canting inboard slightly, perhaps 10 degrees, rather than vertical.

You have a nice amount of camber in the roof beams, but your sketches in post 6 seem to make the camber appear 'deeper' with much more roof visible in side elevation.
I think that if you put on a simple thin fibreglass roof, the actual depth of camber will be less than your sketches, and it will not 'stand out' visually very much when viewed from the side.

The roof could be single skin (perhaps with a layer of 'coremat' in the lay-up - it doesn't necessarily have to be foam cored for stiffness) so long as it doesn't 'droop' between the aluminium supports.
Is it possible to turn the frame around horizontally 180 degrees, so the forward end becomes the aft end?
I am thinking it might look better with just a short 'eyebrow' overhang at the front, and a longer roof overhang at the aft end,

Perhaps have something like a yacht spray dodger at the forward end, between the cabin top and the roof, with zippable / removable sections?
If you put 'solid' sides on to your frame, it will look like a shed, no matter how artistic it is.
But if you have canvas side curtains, with clear windows, then for some reason these always seem to 'stand out' much less than something 'solid' - look at all the canvas enclosures on flying bridges, in comparison to solid 'boxed in' types.
You could have the canvas side curtains with zippers as well so that they can be rolled up on nice days.

PS - just saw your latest post above.
Re the power cat in my avatar, she has 1.5 mm aluminium sheeting for most of the main roof and the flying bridge roof (the plating is 4 mm thick in way of the sole of the flying bridge).
The maximum unsupported panel size is about 3' square, and I have seen a 75 kg man walk across it happily, without making sure that he stayed on the beams underneath - ok, it flexed, but it was nowhere near failure. And the operators have been walking on it for 12 years now.
 
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Helped a friend build a raft a long time back - deck weight was a similar problem and solution was 2 x 3mm ply sheets with a 25mm closed cell polyurethane sheet sandwiched between! Lightweight and astonishing how much stronger it was than the 12mm sheet of ply he started with :cool:
 
Re the power cat in my avatar, she has 1.5 mm aluminium sheeting for most of the main roof and the flying bridge roof (the plating is 4 mm thick in way of the sole of the flying bridge).
The maximum unsupported panel size is about 3' square, and I have seen a 75 kg man walk across it happily, without making sure that he stayed on the beams underneath - ok, it flexed, but it was nowhere near failure. And the operators have been walking on it for 12 years now.
Click to expand...

Thanks for that info....
I'll go and get a piece of 1.5 mm ally to try across the frame to see if it will support my 85 kg weight! This would be the perfect solution.....zero maintenance



Coloured bootstrap...blue hull.....

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rbcoomer said:
Helped a friend build a raft a long time back - deck weight was a similar problem and solution was 2 x 3mm ply sheets with a 25mm closed cell polyurethane sheet sandwiched between! Lightweight and astonishing how much stronger it was than the 12mm sheet of ply he started with :cool:
Click to expand...

That's a fantastic suggestion, and you get insulation as well. Will investigate...:)
 
rustybarge said:
Thanks for that info....
I'll go and get a piece of 1.5 mm ally to try across the frame to see if it will support my 85 kg weight! This would be the perfect solution.....zero maintenance
Click to expand...

When doing this, be aware that if you simply lay a sheet of ally over the framework, and then try walking on it, it will have much less stiffness compared to if it is physically attached to the framework (eg riveted).
This is because the ally sheet is like a simply supported beam, whereas the riveted sheet is like a beam with 'built-in' ends.
Because the ends are locked in, the sheet cannot slide sideways when you press down on it with your weight - and it will do that if the sheet is simply resting on the framework.

The blue hull with the white boot-top looks very nice.
 
rustybarge said:
Thanks for that info....
I'll go and get a piece of 1.5 mm ally to try across the frame to see if it will support my 85 kg weight! This would be the perfect solution.....zero maintenance



Coloured bootstrap...blue hull.....

View attachment 35450
Click to expand...

Bajansailor said:
When doing this, be aware that if you simply lay a sheet of ally over the framework, and then try walking on it, it will have much less stiffness compared to if it is physically attached to the framework (eg riveted).
This is because the ally sheet is like a simply supported beam, whereas the riveted sheet is like a beam with 'built-in' ends.
Because the ends are locked in, the sheet cannot slide sideways when you press down on it with your weight - and it will do that if the sheet is simply resting on the framework.

The blue hull with the white boot-top looks very nice.
Click to expand...

Thanks bajan, that colour scheme really works wonders....

How about a curved windscreen like on this rebay rib....just a bent sheet of acrylic.

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