- Devoted to the Bertram 31 boats around the world!

PVC Guard Rail Installation -- Bertram 31

-- PVC Guard Rail Installation --

The newly designed PVC guard rail by Capt. Alex Whitaker is now available!

Orders can be arranged by contacting Alex at 714.329.3030 or by email at

Removal of old aluminum rail and Installation of PVC rail:

Removal of the old aluminum rail will be somewhere between an easy 2 hour job or a pain in the butt all day job.

If your boat's original rail was installed with all through bolts and the interior is intact, (most of the bolts will be hidden behind cabinetry, head liners, etc), and you'd rather not dig into the interior to access the bolts, your best option is to make a diagonal cut in the rail passing through the shank of the bolt.

This process will be done with a sawsall and metal 4" cutting blades. Stainless steel is brutal on saw blade, so figure that you'll only get about 6 - 8 bolts cut per blade. Buy them in bulk if possible. The resulting cut in the rail will be relatively minor and can be welded back if you care to use your old rail as a salvage item.

The alternative to sawing is to use a high speed grinder and grind, at a 90° angle to the rail, the head of the bolt away. This method is going to make repairing the rail much more difficult and costly, but if you're not interested in saving the rail, no big deal. Take it to a metal salvage yard and scrap it out at the current rate.

This will leave the bolt, minus the head, still in place. Cut the bolt flush with the hull flange if necessary and push the remainder through to the inside.

If you have an original installation where the only through bolts are at the rail joints and the rest are are screws, then your job will be considerably easier. Cut the through bolts as described above and then using a pry bar and wooden wedges, just peel the rail off. There is not much holding power from the screws in the flange and they will strip out relatively easy.

Once the old rail is down, remove any remaining bolts and clean up the area that was below the old rail. Plug all screw holes with epoxy and high density filler. Look over the flange joint and fill any significant gaps. The cap and hull flanges are pop riveted together with aluminum rivets. Any really bad gaps between the flanges should be epoxied, squeezed together with a clamp or pair of vise grips and a sheet metal screw driven in to hold it secure. Use a pan head screw and cut the excess length off flush with the underside of the hull flange.

Go around the boat and scrape off all the old caulking, then clean up the landing areas with solvent. You're now ready to install the new PVC guard rail.

Begin your installation at the bow. The new design uses a bow section that is a full 22' long, shaped and fitted for the B31 bow. It is not difficult for just one man to get this large section in place by using a couple of pieces of light weight cord and making temporary slings. Measure back from the forward curve, on both sides, about 4' and put a temporary screw in the center grove of the rail. Do the same a foot or two from the ends. Toss two sections of the cord across the bow, hook the ends of the cord to the screws on one side of the rail. On the other side of the boat, pull the cord, hoisting the other side well off the ground, and secure the cord to the screw. A couple of adjustment moves and the rail will be near deck level.

From up on the bow, adjust the cords so that the rail is correctly over the hull flange and moved back as far as tension will allow. With a 2' clamp at hand, move the rail a foot or two forward and with a quick and forceful move jamb it back as far as possible into place. Holding this, clamp it and adjust the clamp to squeeze the rail against the boat. Use a temporary screw close to the center of the curve to lock the rail into place. Make the pre-drilled screw hole in the PVC rail large enough that the screw isn't biting into the PVC. Adjust the clamp tighter and take up on the screw. repeat this until you have the rail as snugly against the boat as possible.

Measure back on each side about 14" and add another screw. All three of these screws are temporary and just to get the rail holding into place.

Measure all of the screw placements so that they will not coincide with the stainless steel rub rail when it's installed. Most stock stainless steel rub rails have hole drilled every 7" so your pre-drilled holes should start off with a measurement that won't likely coincide. From the center bow screw, measure back on each side 2" and make this the placement for next two guard rail screws.

From these points, measure all of the rest of your guard rail screw holes to be 7" apart. With the second and third guard rail screw 4" apart, and the stainless rub rail centered on the bow so that the bend point is between two holes, the rub rail screws will always be about 1 3/8" aft of the guard rail screws. You want the apex of the bow bend in the SS rub rail to be between two holes, not centered on a hole. The hole marks nearest to a joint in the PVC guard rail will need to be adjusted to land about 1 1/2" from the joint. Just make sure they won't conflict with the rub rail holes.

The 2 side pieces of PVC guard rail are in matched sets. The factory length for the extrusions are 22' in length and have been cut by hand saw in the middle. Be sure that you're working with a matched set on each side of the boat.

From the bow piece joint, start one of the matched pieces with the squared butt to the bow butt. Using duct tape, tape the section to the boat with the joints as close together as possible. For the time being, only tack the rail sections into place using randomly spaced 2" deck screws.

The next few images show the guard rail joints being trued up and fitted along the side.

At the point that the aft side section is fitted and running freely past the transom corner, remove it and fit the transom section.

Replace the aft side section, but overlap the butt joint. This will allow you to work the transom corner miter with ample material and then come back and match up the side joint.

With the transom and side sections over lapped, mark the basic miter cut, but cut beyond this mark so that the two sections can be worked simultaneously

The transom corner is a compound miter due to the curve & angle of the transom and the compound curvature of the hull side. It will be necessary, therefore, to pay close attention to the matching faces of the miter cut to insure that you have a clean joint with little or no gaps when finished.

The image below shows the final result of the transom corner. The corners have been rounded over to facilitate wrapping the stainless steel rub rail.

Best regards,

Patrick McCrary

Capt Patrick McCrary
834 Scott Dr.
LLANO, TX 78643


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