COLUMBINE - The Boat

[b.lindsey]

Nice new addition Robert   Merry Christrmas 

Bill

[Robert Hornby]

Back from holidays and motivation returned wood shavings are being made once again.
The first rib I made I cut the concave profile from cardboard and trimmed it to get a reasonable fit to the hull. Then using the template I drew the shape with pencil to the timber then bandsawed the wood and finally sanded it to fit the hull. Very time consuming and there has to be a better way of transferring the hull shape to the wood. I few hours of contemplation brought me to a tool I used as a junior draughstman many many moons ago called a flexible french curve, but where to get one was going to be a greater issue. Mr Google provided the answer and via ebay I had my curve for the princely sum of $5-60.



The curve was pressed into the hull and then transferred to the wood where I could draw the pencil line ready for cutting.



The band saw made short work of cutting the wood along the line.



The concave profile after the band saw cut.



Next was to fine tune the profile on the disc sander to give the good fit to the hull.



With the shape good enough the concave profile can be drawn by just following the outer one 6mm away and drawing the end 'TEE' part which will support the decking timbers.




More band saw work and sanding sees the rib complete





I have glued the rib in place with high strength wood adhesive and it does a very good job




Each rib is now only taking about 1 hour to make so with around 24 to go I will be here for a while yet. Each rib will be unique i.e. not two the same.

Robert

[steamer]

The other alternative would be to laminate them from 2 or 3 layers of thinner stock in place against the hull    You could either put some packing tape in first, laminate them, remove the tape and then bond them in, or just glue them in 1 layer at a time.   I would prefer the first method as I could then shape and sand them, and finish them outside the hull like you are now....much less mess and a neater job.

Or you could do it this way.  This is coming along wonderfully!   Either way is consistent with full size practice.

Keep it coming, I like boats!

Dave

[Robert Hornby]

Thanks for the response Dave, I had considered laminating the ribs as you suggested but decided against it as making the deck support part would not have been so easily done. Also making all the laminate strips would have taken time as well, although time is not really important to us retired folk. Also, I doubt the original boat would have had laminated ribs, but I will take advice from more knowledgeable people than me on this one.
Bob

[crueby]

Full size boats get built with every imaginable method, just like full size and model engines! On simaler size models I've done sawn, laminated, and steam bent frames. Each worked about as well.

Lovely work, watching along...

[steamer]

Thanks for the response Dave, I had considered laminating the ribs as you suggested but decided against it as making the deck support part would not have been so easily done. Also making all the laminate strips would have taken time as well, although time is not really important to us retired folk. Also, I doubt the original boat would have had laminated ribs, but I will take advice from more knowledgeable people than me on this one.
Bob

I used saw cut and laminated construction in my 25' steam launch.   Both are acceptable methods and work very well

Herreshoff used steam bent frames in a mold of the hull pulled up against the ribbands of the mold with the boat built up side down.    If he had Epoxy back then I'm sure he'd a used it.

Dave

[Robert Hornby]

Many moons have passed and I have finally completed the ribs 


The next part will be the floor/base for the boiler and engine. It is my intention to be able to remove the power plant as one item to enable maintenance work outside the hull. I will be fibre glassing the wood supports to the hull and then screwing (M5) the floor to them.

Robert

[Ye-Ole Steam Dude]

Beautiful workmanship and I will be following along.

Thomas

[Tennessee Whiskey]

Nice to see an update Robert. I hope you haven't been neglecting "my Cobra" during the progress . Carry on and I'm following.

Cletus

[Robert Hornby]

Cletus,
Be assured "your" Cobra is getting the attention it deserves, ie getting out at least fortnightly.
Robert

[b.lindsey]

Good to see you back on it Robert. Never done any boat work, model or otherwise, but it fascinates me.

Bill

[Robert Hornby]

Couldn't help myself, had to see hoe it looked with the boiler and engine in roughly the right place. As the boiler is quite far forward I am thinking most of the ballast will need to be at the stern. I have calculated that the whole finished boat will need to be around 11kg to achieve the correct water line. I am expecting to add around 2 to 3kg of lead.



Robert

[Ian S C]

Robert, If it's going to have radio gear, maybe the placing of the batteries will cover most of the balast problems, with just a bit of lead in the bilge to get the right water line. It's looking good.
Ian S C

[Robert Hornby]

I have had a bit of a change of direction with the boat and decided to convert it into a model of an 1890's era aircraft carrier, still some detail to work out.

[Ye-Ole Steam Dude]

Robert that is a novel idea and this will be an interesting build.

Thomas