Tuesday, January 19, 2016

Bimini Renewal

This post originally appeared on Windborne in Puget Sound as a series of three posts; they have been collapsed into a single, longer post here.

One of the things about owning a boat for a long period of time (or ageing in general, for that matter...) is that you get to see the effects of time.  They are almost never kind.  But to avoid becoming morose, let's keep this focused on Eolian's cockpit canvas.

Way back in 2003 we had our cockpit canvas renewed by Barrett Enclosures in Seattle.  They did a masterful job.  But that was 12 years ago.  In the intervening years, I have had to redo almost all the stitching (because I made a short-sighted decision to use the somewhat less expensive "UV Stabilized" polyester thread instead of the Teflon thread), refresh the Sunbrella's waterproofing on an annual basis, and deal with slow but inevitable fabric shrinkage.  It is a sad thing to me to see the sorry state that things have reached, from such initial beauty.  So, it is  time to do that "once in a lifetime task", a second time.  New cockpit canvas is needed.

But this time, instead of investing more than 6.500, I decided to give it a try myself.  Already having a Sailrite LSZ-1 makes this a possibility.  So I reviewed Sailrite's excellent online videos, ordered a bunch of Sunbrella, fittings, and notions from Sailrite, and set to work.

After uneventfully patterning the aft bimini panel, I encountered the first problem:  There was no place on the boat large enough to lay out the pattern on the cloth.  We were able to get about 3/4 of it on the cabin top, so we did that and then folded the marked section up enough to get room to finish.  Yes, I know that this process was fraught with opportunities for errors to creep in.  But within the tolerance that we were working with (about 1/8") I think we did OK.

But there are a lot of fabric pieces involved in the aft panel.  Altogether 7 more pieces were needed, besides the obvious big one.  And then the space thing reared its head again.  Working with the LSZ-1 on the edge of the saloon table, I was able to sew the long seams by letting the completed section pass over the table and then off the far edge, on its way back to the floor.

On a project like this, fabric management is always difficult, especially when working in a limited space (tho not as big a problem as this).  My recommendation:  always, ALWAYS use  seam-stick tape, 3/8" for normal seams and 1/4" for zippers.  It is a lifesaver.  And don't be in a hurry.

This last weekend, I finally got the last of it done and installed it.  But sadly, somehow I managed to get the locations for the Common Sense fasteners for one of the aft side curtains off slightly.  Rather than make another set of holes in the new piece, I am going to relocate the eyelets in that side curtain instead.  The thinking is that the side curtain is old and will be replaced anyway at a time in the future much nearer than the just-completed panel.  And because of this, I am not going to show you a picture of it.  Yet.

The plan is to move ahead with the other roof panels in sequence - the loose center panel that connects the dodger to the bimini, and then the top panel of the dodger.  When redoing the top panel of the dodger, I will be revising Barrett's design, making the top panel and the front panel separate pieces - the thing is just too unwieldy for me to handle as a unit.  And in fact, it looks like Barrett made the roof and front of the dodger separately, and then stitched them together as a final step.  I will use Common Sense fasteners to hold them together instead of stitching.

So.  I can say at this point, nearly 1/3 done with the top of the bimini and dodger, that with Sailrite's instructional videos, their tools and their materials, this is a doable project.  It is complex and requires constant attention to detail, but it is doable by the cruising sailor, at a savings of 90% over the cost of having a professional do the work.  But don't figure on getting it done over a weekend...

OK, as promised, here is the result.  I am one third done with redoing the bimini and dodger. That is, I have completed the bimini roof (I am excluding the side curtains and the dodger front from consideration at this point in time - the vinyl is still serviceable, and because these surfaces are not horizontal they have not suffered sun damage to the same extent).

I think it came out pretty good. In fact, it looks about as good as the original did when it was new and before shrinkage pulled everything tighter than a drumhead.

So, can you do this yourself?  The answer is yes.  But first, I strongly recommend that you view the following Sailrite video: How to pattern a bimini. There used to be another video on the website that took you thru the process after patterning, but they have apparently taken it down. But if this whets your appetite, then get this DVD and study it, thinking thru each thing that is done, and understanding why it was done.

First, nomenclature.  In the roof panel I made, there are three major piece types:
  • The roof panel itself - the largest piece of fabric by far
  • The sleeves.  These pieces of fabric form the sleeves which zipper around the tubing at the front and rear of the roof panel.  
  • The tails.  These are the narrow strips of fabric that hang down at the front and rear of the roof panel - they serve as the attachment points for the side curtains (at the rear - on mine you can see the rivets holding the Common Sense fasteners) and the center panel (at the front).
  • There are also some narrow reinforcing strips that go on the bottom edges of the sides to strengthen the attachment points for the side curtains.
If you decide to tackle this project I have the following recommendations for you:
  • Use Tenara Teflon thread.  I can't recommend this strongly enough.  The special "UV resistant" polyester thread will last approximately 5 years (in the PNW - less in the tropics).  The Tenara thread will last indefinitely - far outliving the fabric.
  • When sewing, use the basting tape that Sailrite sells.  The stuff you can buy in your local fabric store is designed to wash out and is a far weaker adhesive.  Use 3/8" for most seams and 1/4" for zippers.
  • When installing zippers, make sure that they will be covered - that is, protected from the sun.
  • Tools - you should buy these tools and consider them part of the cost of the bimini.  Your cost will still be far, far less than what you'd pay for professionally built canvas.
    • First and foremost, a walking foot sewing machine.  You just can't do this work with a home sewing machine. I have a Sailrite LSZ-1 and love it.
    • A binder of some type for applying bias edging tape
    • This nifty tool set for installing male Common Sense fasteners
    • This punch for installing Common Sense eyelets
    • Please note that my project did not require installation of snaps, Lift The Dot fasteners, etc. so I have not included tools for their installation here.  But if you need these fasteners you should look carefully at the tools that Sailrite offers.
  • If you are doing what I did, replacing an existing bimini, you can pattern right over it without removing it.  This allows you to get a better take on where the edges need to be, and saves a lot of labor.  You should apply the seam stick tape directly to the old bimini without an intervening layer of some other kind of tape.  It holds better, and yet can still be removed after the patterning.
  • For the panel to install correctly and fit well, it is critical that you consider and think about things like this:
    When patterning, the line defining the front and rear seams (where the sleeves and tails attach to the roof panel) should be made, not on the top of the tubing, but rather 90° away on the front (or rear) side of the tube.  Doing it this way makes it simple to attach the other edge of the sleeve.  Magically, you can just smooth the sleeve flat against the roof panel and stitch the zipper where it lays, without making any allowance for the wrap around the tubing whatsoever. I know that doesn't seem right, but it is.  Get out some strips of paper and try it out - I know that I had to in order to convince myself.

    If on the other hand you need for the seam to be on top of the tubing (as for example if the seam joins two adjacent roof panels over an intermediate support), then you cannot simply lay the sleeve flat to determine its attachment point to the roof panel.  Instead, lay it flat, mark the edge, and then move it back 1.25 inches (I think...  get out your paper strips and confirm this number - it will depend on the size of your tubing) and attach it there.  Because in this case you do need to account for the wrap around the tubing, and it's a surprisingly large amount.

    If you should use a top seam for the forward edge of your roof panel, you will need to make the tail wider by half the diameter of your tubing so that it will extend the desired distance.
  • You will face a decision whether to use "hang down" tails or "tuck back" tails.  Hang down tails are just straight rectangular pieces of fabric; tuck back tails are contoured to match the edge of the bimini to which they will be attached.  I initially made mine with the hang down tails, but I was disappointed with the way they, well, hung.  Because they are straight fabric pieces, they do not follow the contour of the bimini - they just look bad.  I made new tuck back tails, ripped out the seams and installed them.  
  • When laying out the sleeves or the tuck back tails, the video may encourage you to use the pattern to determine one edge and then laboriously lay out a second line the desired distance away by making a series of markings perpendicular to the original line.  This is unnecessarily tedious.  Instead, lay out the first line using the edge of the pattern, pull the pattern back the desired amount, and lay out the second line, again using the edge of the pattern. 

As you can see, there are two more panels that need to be reconstructed. And that sail cover is looking pretty shabby too...

A quick revisitation of the tails issue, with an illustration.  And then I promise I will shut up about it.

Consider the forward edge of the aft bimini roof panel.  Because I am lazy, I originally made the tail as a hang down tail.  That is, the tail was a long skinny rectangle - easy to cut, and minimal fabric usage.  But because it had no curvature, it did not match the contour of the front edge of the panel.  Consequently, after installation it had a scalloped appearance and made a loose fit to the center panel:

Hang down tail.  Bow is to the left, and new panel is on the right
What is worse, with Eolian moored facing into the weather, when it rained (and oh, does it rain here in the PNW), the wind blew the rain under the edge of the tail and into the cockpit.  In fact the tail acted as a funnel, actually scooping in rain.

Tuck back tail - doesn't that look better?
So I picked all the seams and took apart the front edge of the panel.  And I cut fabric for a new tail, this time a tuck back tail - contoured to match the forward edge of the panel.  The result is gratifying - look how tightly it meets up with the center panel!  The built-in curvature makes the edge of the tail actually press down on the center panel - wind-blown rain is excluded (tested less than an hour after reinstallation... this is the PNW after all).

So far, I cannot think of a situation where I would use a hang down tail.

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