Saturday, March 10, 2012

Helm Retrofit

Nordic Tug 26-102
Helm Retrofit

I decided to change the helm of nautica as I was used to a “wheel” on our sailing boat and could not become comfortable with the spoked version which I found awkward to use 
( personal thing I know but there it is ). I was looking for something different.

FIG 15,16

Most of the wheels on new boats, if wood, seem to be made using segments on the circle joined together.

I have always liked the “teak and holly” look and used teak and maple (holly is very brittle apparently and more difficult to obtain) on the cabin sole of our previous sailing boat  .
So to achieve my “wheel” feel and laminated for appearance, I elected to investigate how I would go about it.
I don’t think I have ever spent so much time investigating ,eliminating possibilities, doing umpteen mockups, making jigs but it all keeps the mind ( read brain ),working and the end result can be very satisfying.

So to the process.

I elected to go with teak and ash. Ash was chosen as it bends very easily compared to maple ( my preferred coloration) but the chance of breakage was too great.
I dismissed steaming as it seemed to complicate the process.
By choice I went with a 1” diameter wheel. Everyone will have a favorite diameter that “feels’ right so change to suit.
Important thing here is that the height I.E. the flat dimension or width of each laminate needs to be at least ¼” larger than your finished diameter.
This allows trim room as laying the strips may not end up exactly all flush.
Epoxy is VERY slippery.
Speaking of epoxy I used Lee Valley G2 two part epoxy glue, wiping the teak down with acetone just prior to gluing.

Miscellaneous tools included clamps, screws, etc.
The list is long but if you are attempting this project you probably have more tools/experience than I so I won’t expand on this.
One system of holding the individual strips is with clamps around the perimeter of the form  with a metal or wood strip cover to spread the point load of the clamp. This requires a LOT of clamps and I was not convinced about spreading the load. Thought of using a very long hose clamp if I could source one that long. Found one sold by Lee Valley. It is brilliant (my opinion) as it comes as 13 feet long with about 6 worm drive / winders. Cut in half allowed me to put two bands on at the same time and still have sufficient excess to go through the worm drive. Reusable , adjustable SS for future use…the product ticked all the boxes.
Just noticed that I drew FIG 6 with only one clamp. I used two.

How I went about it.
Cut 2 pieces of ¾ “ ply to 22” diameter (yours may vary of course). I used a router mounted to a board with a screw at the center to obtain a perfect circle.
I should explain the diameter. I originally assumed I would make the wheel the same diameter as the existing spokes but when I made a mockup with a garden hose, it appeared too big for the confined space of the wheelhouse. I made a second mockup, FIG 17  and settled on the 22" ID
FIG 17

I screwed the circles to a back board made about 8” wider than the diameter of the "plug".  As long as it provides a platform for screwing adjustment blocks and general layout use.
I used masking tape on the vertical and horizontal surfaces which would be subject to glue spillage and make it reasonably easy to remove the form. One could use any material but I discovered that at least the masking tape being not as "slippery' as say 6mm poly, did not move. As you will see six hands come in handy so if you have less to hold, adjust, tweak the better.
I made each laminate an  even number relative to the diameter. In my case 1” diameter. I wanted to have the teak on the outside of the wheel and the ash on the inside.( hence 10 strips). The number 10 came from experimenting to determine what thickness would bend easily without the risk of breaking and not too thin to make a ridiculous number to glue. 
I should mention at this point that one could of course go with all teak and make it simpler. The process is the same with any material but make sure you ask a knowledgable person about appropriate materials for bending. Breaking one strip lathered in epoxy and sprung ready to pounce is not the best option.
The illustrations explain measuring each band prior to gluing. FIG 4
Fine tune the cut as many times as needed because you only get one chance when ready to put the hose clamp on finally with the epoxy applied.
I dry fitted each one several times to make sure I had the correct length. 
Clamp / mark / cut…. clamp / mark / cut . It is better to end up with a slight gap at the butt end than find they are too long when you cinch up a glue laden strip. Fixing that would not be fun.
I had intended to do two maybe three bands at a time but at the dry fit stage abandoned that idea. One at a time is my only way to control all the elements and not get into trouble.
Lather up the band, lay it down against the blocks (see FIG 4) , slip the separation poly on the outside, FIG 6, then the sacrificial strip on that then the clamps on that. No you can’t do this with two hands….I could not anyway so had help just for this process. Once it is under control you are back to two hands.

I staggered the joints for strength and aesthetics and it does not read negatively even with the teak/ash combo. It would be a lesser issue with all teak.
At each band install make sure the strips are held down so they do not slip upward during the epoxy setup.
I made blocks that were screwed down over the new laminate during that setup period.
Repeat the process for as many laminates you have and I will guarantee it gets better as you go through the process.
By the time you are finished this part, all is well with the world.
I pondered the removal of the plug at length worrying that one mistake here would ruin the project.
Unscrew the base , remove the screws from the two ¾” layers.
FIG 7 tells the story. Cut as close to the perimeter as you can without risk of damage . I went to about ¼” away with a good quality jig saw.
I was able to knock out the remaining plug leaving the 1” square wheel ready for the next stage.

FIG 18,19

This is where I chickened out on doing the routing to turn it into a 1” diameter. My skill/ equipment level convinced me to have my friendly millwork company run it through their router.
The transfer of the wheel internal diameter to the spokes was achieved by measuring and re-measuring. As usual measure twice, cut once. In my case about at least 5:1. ONE mistake at this stage and it is all over.
No doubt there are many ways  to cut off the spokes evenly. I elected to make up a jig that held the spoke at right angles to the table saw blade. It worked really well for me.
Round off the stubs ready for the next stage.FIG 9,10,11

I did not want the wheel to sit directly on the spokes for aesthetic reasons so used a 3/8" brass pipe section separator as per FIG 12,13,14 and FIG 21
I predrilled the spokes and the wheel by hand/eye as I do not own a drill press.
Sweating bricks but it all lined up.
I assumed a #8 screw would be sufficient but needed a 4” length to really bury into the spoke. My supplier of SS screws only had #10 X 4” so what the heck #10 it is. I think I could lift the boat with it.
Final stage of fabrication was installing the wood plugs.
I elected to go ash plugs in the teak band for a little detail touch.
Sanded everything down and finished the whole wheel, existing and new with polymerized tung oil.

FIG 20,21

Hope this dissertation is of assistance and not too confusing. 
If there are any details missing please do not hesitate to contact me.

Nordic Tug 26-102  nautica

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