Log Build: Crab (a crane boat)

Swabbie

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#1
Had a lot of fun building my first boat, the Bingal. It was made from two bow sections. This one, the Crab, will basically be made from two stern sections.
I intend to make a crane boat. I think it may be a combination of these two designs:





I like the idea of two cranes. It gives that animated look of a crab _ "It's alive!"

Anyway, I had made a start from the kit left overs from the Bingal. The bulkheads and keel have been glued.



Please note: I think this build will be a slow one. I have other tasks to do with the bridge diorama, and this boat will be tinkered with, now and again, at night.
 

Swabbie

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#2
Decided to use one large hydraulic crane near centre of boat, and possibly a derrick hoist at bow end of boat. I figure that a double hydraulic crane is a specific work boat best suited on a floating platform. Crab boats usually seem to only have one large hydraulic crane, and they are ocean fishing boats with a deep hull for storing the catch (as far as I know ---I am just learning).

Anyway, because the two stern sections are longer than the whole kit boat, the planking is too short. I had to chopped one end off the framework.
Even the chopped version is still longer than the Bingal (two bow sectioned boat).



Made a quick sketch of the large crane, and started building it from scrap timber. I don't have a lathe, or router, etc, so I use the old tools of saw and files. The job still comes out alright.

 

Swabbie

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#3
I have been enjoying building the crane so much that I have neglected to do what I said I would.
Anyway, I wanted to build a big crane, and it sure is turning out big. Perhaps too big. I have learnt a lesson from this, and that is to FIRST draw the plans to actual size according to scale.





It's to late now to rebuild it. I put in a fair bit of work into it already, which I have no intentions of wasting it. I am thinking about changing the boat to something other than a crab boat. Something that a 60 foot (20 m) boat with a use of a huge crane. Have you any suggestions?

 

Swabbie

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#7
The crane looks fantastic, a great feat of engineering. You could build a diorama with your boat pulled along side a dock with the crane mounted on the dock. And have the crane offloading the boat.
Thank you Don for compliments and 'likes'.
That sounds like a good idea, especially if it showed that the boat might be slipping (Oh oh!).

Unfortunately, the crane is for another intention, the Bridge and Boat Diorama, still in progress. Why I cannot use your idea is that the display landscape has no crane on a dock, which would be a landscape fixture; where a boat is not, for it is transient. I am trying to stick with the fixtures, and play havoc with what is transient. But not too noticeable, not like giant octopus tenticles coming out of the water to wrestle with the crane (though very tempting).:D
 

Swabbie

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#10
Very good appearance...... it is looking very good......now you need only a barge in the correct size
Yes, that would be good, yet I am still going to carry on with the one I got. I had another search on the Internet and their are vessels that look small, yet have a huge crane. So it seems viable to some degree.





So far I have been thinking about a boat that replaces large navigational (red and green) bouys; but that won't explain why it is up the river, because huge bouys are for the ocean.
Or a simple crane boat used for salvage. Have it hoisting up a car, or sunken recreational boat, out of the river.
 

Swabbie

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#13
This is a very cool project, I think a diorama with the crane pulling up the plane would be outrageous
A plane seems a bit way-out-there, but then again, a biplane would be more feasable... a stunt plane crashing after flying under the bridge. It would be totally mangled / bingled.

Would be good to have part of a flying circus camped on the sparse south side. I can imagine the museum president and curator pulling out their hair, seeing their diorama running riot. :D:D:D
 

Swabbie

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#15
The crane has really come to life now you've painted it. The large navigation bouy could have been built up river and is being tested before it's taken out to sea,
Cheers Andy
Thanks @Aginvicta for that justification. It added extra weight towards using the boat for bouys. I am still undecided, yet still researching for other uses for a crane boat.
 

Swabbie

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#16
Marked the waterline on all the bulkheads (the boat will be in water). Then added the planks along that line.


Then I started adding the planks in between.

I suffered an injury from pushing in the pins by hand. It is hard to penetrate the plywood. As a result I damaged my nerves in my index finger. That finger is repairing, but after 24 hours I still feel some numbness at the finger tip. I tried using pliers, but it is difficult the hold the boat with one hand while with the other hand trying to keep the pin steady with the pliers under plressure. Everything went sideways and I broke the plank. Have you any tips for me?

Finished the planking. I only planked what will be above the waterline.


Then I filleted the boat ;), and sanded the bottom nice and level.