Two speed capstan from USS Kearsarge

[crueby]

This is a model of a capstan (used to haul ropes for cargo, docking, etc) from plans for the battleship Kearsarge in the National Archives, drawn in 1897. The main parts were all 3D printed, with metal axles and internal pawls. In one direction it is direct drive, the other direction it uses an internal planetary gear set to reduce the speed of the main drum, which gives more power to the drum.


Here is a short video of it in operation - there is a small piece of blue tape on the main drum to make it easier to see the difference in speed when the top is rotated in either direction. Those square holes around the top would have long wooden push bars inserted into them so multiple rows of sailors could line up and walk the capstan around.
<a href="https://www.youtube.com/watch?v=G_chiDV-um0" target="_blank">http://www.youtube.com/watch?v=G_chiDV-um0</a>

Some pictures of the internal mechanism, taken from the 3D CAD model I drew from the original plans. Here is the base, showing the outside ratchet recesses that keep the load on the rope from pulling the capstan around backwards. Near the center is another smaller set of ratchet recesses that keep the internal gear plate from moving in one direction, allowing it to spin the other way.

This shows the planetary gears on the inside, they are held by a plate with ratchet blocks that drop down into the recesses in the base.



This shows the top of the main drum, with yet another set of ratchets, these go the opposite way, and control the way the top section acts on the drum. In one direction it engages the drum, the other way it free spins, allowing the gears to operate. The center post is fixed to the bottom plate, the drum and top section spin on the post. The top section has a tube sticking down that holds the sun gear in the center, so that gear spins with the top section.


Pretty slick mechanism - the original would have been mostly cast iron, with steel and bronze for axles and bearings. Manually operated rather than with an engine, but I figured people here would still find it interesting, not many realize that some capstans (not all) were two-speed mechanisms. Modern sailboats have miniature versions of these to help pull in the sails, in the 6" to 10" tall range with a crank handle that fits into the top. Inside they are basically the same as this, interesting that they date back to the 1800s. Fun little side project, the 3D printer did all the hard work, I just had to make the few metal parts for the axles and internal pawl blocks (a pawl is the moving part of a ratchet that makes the clicking sounds).

Chris

[Dave Otto]

That's pretty neat Chris!

Dave

[wagnmkr]

I have to ask ... Have you invented another day???  Seven thousand new parts on your latest engine, and you still have time for submarines and capstans!  Superman has nothing on you.

Cheers

[crueby]

I have to ask ... Have you invented another day???  Seven thousand new parts on your latest engine, and you still have time for submarines and capstans!  Superman has nothing on you.

Cheers

I stole on of Dr Who's spare Tardis's... That got me over into the other universe with 9 32-hour days per week!      


There was not actually a lot of build time on this capstan, the profiles on the barrel and other parts were traced in CAD from scans of the vintage plans, then set up the 3D printer and walked away for hours and hours while it printed the parts. The metal parts were just a few simple axles and tubes.  If I had machined out the parts from bar stock, it would have been a major build, dont have a clue how I would have made the main barrel without CNC - with the 3D printer it took 10 hours to print the barrel after the minute I spent turning it on, loading the filament, and hitting 'start'.

[Kim]

That is a pretty cool model of a capstan, Chris!

Are you going to upload the files to printables.com or something? (He asks for no reason in particular  )

Kim

[cnr6400]

Very nice Chris! Great mechanism design. The model works well. Now what car engine are you going to get the shop elves to lift out with it? Hope they don't try and order a beverage at the capstan bar(s). 

[crueby]

Very nice Chris! Great mechanism design. The model works well. Now what car engine are you going to get the shop elves to lift out with it? Hope they don't try and order a beverage at the capstan bar(s). 

They did try to eat at the capstans table, but they got dizzy and fell off...  The captain had them thrown off the ship. 

[crueby]

That is a pretty cool model of a capstan, Chris!

Are you going to upload the files to printables.com or something? (He asks for no reason in particular  )

Kim

The CAD model was done at more life-size dimensions, scaled it down in the slicer. It took a test to get the gears to mesh right, my printer tends to print things about 1/4 mm oversize so they bound up first time.

[crueby]

For any who are interested, attached are copies of the plans (scaled down slightly to make them fit here but still readable)

[crueby]

third file

[crueby]

I've done a lot of digging on the National Archives (USA) site, not a lot of steam engine plans there, but they do have plans for several interesting things from the battleship Kearsarge, including the steam powered steering engine system (the really big brother of the one I built here recently), as well as the steam powered chain winch and rope winch, which (say that 3 times fast) were together in a deckhouse on the foredeck. Separate steam engines for each winch, nested together in one unit. The rope winch has two speeds. Both have two cylinder non-compound engines. They are near the top of my build list - dont know if I'd do the steering engine or the winches first.
Did a lot of digging, and they don't seem to have plans for any of the main ship engines, fortunate that Dave had the ones from the Ohio from another source! They do have a number of plan views for things like the steam launches that Tghs is building his wonderful model of at the moment, possibly some of the same plans he has in his book.

[Admiral_dk]

I newer knew that the design is that old .... as I seem to remember them showing up on boats (and Dads magazines) in early Eighties 

Thank you for sharing Chris       

Per

[crueby]

The earliest references I've seen to this kind of geared capstan is early 1800s, a British naval captain patented a version of it. Same basic mechanism as is still used on small boats today, though they are much smaller than the original!