[vanguard64]

Hi,
I have to manufacture new cap rails for my sailboat. The wood I will be using is Iroko and I will be cutting the new curved caprails out of 6" X 8' 7/8 inch boards. Each segment of the cap rail will need to be 1 3/4" wide X 8' long. A 1/4" deep X 1 1/2" rabbet will need to be cut on the underside of each caprail. My question is how to best accomplish this with a portable router both in terms of stabilizing the caprail to the work bench and best type of bit to use. Remember that each caprail segment is curved.
Thanks,
Marcelo

 

[vanguard64]

I think ifthere is any curve to the sides of the boat, that you'll almost certainly want to create a template. If the curve is the same both port and starboard, you can flip it over for the second one. You can trace the pattern onto the wood you're using, then rough cut it and so some hand work to get the shape and size just right on the template. Once the pattern is smooth as a baby's behind, you can use it to outline the shape on your final material, then use a jig or band saw to cut the shape, leaving a little proud. You can then use a trim bit with a bottom mounted bearing riding on your perfected pattern to do a nice, clean final work piece. If you have a boat that requires it, you can cut a groove on the underside to match the top edge of the boat. I'd clamp that thing down and mark the groove carefully. This is a general process, but I think it's what you're looking for. I don't think you can hand shape the final wood piece so it matches exactly. That's why you make and perfect the pattern. I'd probably use a strip of half inch MDF for the pattern. You can hold the pattern in place with double stick tape.

 

[vanguard64]

Each gunwale measures 30 ft. I have eight, 8 ft long 1 X 6 boards of Iroko . Here is a picture of the boat and cap rails and one showing a cross section of the rail on top of the deck/hull flange.

 

[vanguard64]

Thank you all for the input. At present, I have a router, a router table, a circular saw, a good jigsaw and hand tools (chisels, planes, etc) I don't mind investing in a band saw if that is needed to do this job well. I have been toiling with the same general approach that desert rat tom has of creating and perfecting the templates, cutting the Iroko with the jigsaw slightly oversize to the pattern, and then using the router with a flush blade. The part that is a bit concerning to me is how to cut the large rabbet underneath the rail since it is on a curve. I can see that being an issue for the router table.

 

[vanguard64]

Yes, I totally agree with that.

 

[vanguard64]

Today I took a 1 X 6 X 8 board of pine and laid it on top of the rail from the bow back to just get a general feeling for my plan. It is in the first 6-8 ft that the curve of the hull is the greatest. I found that due to obstacles like the stanchions which are 1 1/2 inches in from the rail prevented me from utilizing the width of the board to its max capacity so that after the 4th foot the board stuck out over the side and no longer followed the curve. Is there any other way to recreate the curve on to a wood pattern other than laying it on top of the gunwale and tracing it from underneath? Perhaps when they built the boat back in 1970, they cut the rails straight and then bent them using steam.

 

[vanguard64]

That sounds like a good plan. I will give it a go. My plan is to first remove the existing rails and base the pattern on the raised fiberglass contour on which they sit rather than tracing over the existing rails that with time and repeated sanding will not be true.
Thank you for all your input!

 

[vanguard64]

Yes, I thought of that too but I am concerned about the wood springing slightly out of curvature once released from the boat and because it has been sanded repeatedly over the years it is no longer true to the hull shape as it once was. However, if all else fails, I still think it is an option.

 

[vanguard64]

Great idea Desert Rat. The reason you see screws exposed is because after years of sanding prior to varnishing, the wood thickness is down by 75%. Normally, the screws are inset into the wood and the holes are covered with bungs. I guess that after so many years of being on the boat, the rails won't change shape much after I unscrew them. I am concerned about that.

 

[vanguard64]

I plan on making my templates out of 1/2 inch MDF after tracing them from cardboard marked along the hull of the boat. Once I cut the Iroko boards a bit proud, I will route them to the templates. Should I position the templates above or below the Iroko? I plan on using a handheld router not a table. I presently have a flush cutting bit with a bearing on the bottom but if necessary I will purchase one with the bearing on top.

 

[vanguard64]

I apologize. I just realized Desert Rat answered this question on an earlier post. Template on bottom, bearing on bottom.

 

[vanguard64]

Good evening,
I have just completed cutting and perfecting my first 8 ft of caprail template using 1/4 inch MDF. I have also cut a 1 X 6 X 8 board of yellow pine just proud of the template to practice my routing. I also just purchased a Bosch router table for my DeWalt DW 618 router. Tomorrow I will go ahead and use the flush cutting bit as indicated by Desert Rat to cut the wood to the template. My next challenge is to see if I can cut the rabbet on the underside of the practice caprail as seen on the previous post I sent. The rabbet is 1/4 inch deep and 1 1/2 inches wide. The caprail is 1 3/4 inches wide overall. The largest diameter rabbeting bits are not sufficiently wide. What other bit can I use?
Thanks.

 

[vanguard64]

Hi,
For clarification, here are pictures of the template and practice pine. The pine has been flush cut to the template. I still have to round over the edges but my main concern is the rabbet I have to create under the cap rail as delineated by the marker.

 

[vanguard64]

Here is the finalized practice prototype in pine. I first used a 3/8 roundover bit on the edges. Then I used a 3/4 inch wide mortising bit to cut the rabbit on the underside of the rail. I did it using the router table and due to the width, took 3 passes. Thanks to everyone for their input! Now, I have to transition towards the real thing but I have to order the Iroko first.

 

[vanguard64]

Thank you all for all your input and support. You were key players in helping me achieve and finalize this project! Here are some pictures of how it turned out on the port side of the boat. The wood is wet after rinsing off the deck. Since then it has been treated with a danish wood sealer. I am almost finished on the starboard side.

 

[vanguard64]

Thank you for the accolades! When I made the templates for the port side, I had the hope that I could just flip them over and use them for the starboard side. Well, there were enough differences between the sides to necessitate new templates. The boat is not perfectly symmetrical!.