Access Hatch Installation

This was a little project from nearly 3 years ago which I did not post at the time as I kept forgetting to take a photograph of the hatch once installed.

The object was to install an access hatch which would allow me to get at the heads of the bolts that I planned to install when mounting the remote controls for the outboard.

Since installing the hatch I have changed the outboard controls from remote controls to tiller controls so the hatch has now become a bit superfluous, however it will still be handy enough should I ever want to store anything in the side buoyancy tank or if I just want to check inside the tank, although visibility is obviously limited due to the polystyrene packed in there.

Hatch -3 years after fitting

The hatch I chose to install was a Trem Hatch - external diameter 140mm opening size 110mm cut out size 115mm. This was arounf 6 pounds including postage and packaging.

1. The first thing I did was to place the hatch surround against the tank side and after checking that it was in the position that I wanted it I marked the inside and outside edges. This allowed me to determine the location and size of hole that I wanted to cut, as the hole to be cut was 5mm larger in diameter than the marked inside edge of the opening. I chose to use the hatch surround as a template rather than scribe a circle with a pair of compasses as I wanted to see the hatch ring when set against the buoyancy tank just to see how it looked in position.






2. Using an 8mm drill bit I drilled 4 pilot holes at 12 o'clock, 3 o'clock, 6 o'clock and 9 o'clock which would allow me to cut the hole out using a jigsaw. One hole would have been sufficient as the hole was simply to allow the blade to get started, but by drilling 4 it made it easier to stop and start the cut if I wanted to reposition myself while cutting. 

Hole after cutting - smudged pencil marks still visible

1. After cutting the hole with an electric jigsaw, I gave the cut surface of the glass fiber a rub with some sandpaper to remove any rough edges.I also had to remove the marks left by the base plate of the jigsaw which had smudged the pencil marks that I had made when marking out the hatch position. – see photograph.
2. With the hole cut, the next step was to cut away some of the polystyrene which fills the buoyancy chamber - this was to allow me to get to the end of the mounting bolts for the remote controls. This was a simple task which I used a Stanley knife saw for.
3. After checking that the hatch surround fitted correctly I offered it up and using one of the pre-existing holes for the 8 fixing bolts as a template, I drilled a single hole through the fiberglass of the buoyancy tank. I would drill the remaining seven in stages as I fitted the hatch surround.
4. After applying a bead of silicon to the hatch surround I put it in place and after inserting a single M6 stainless steel bolt (Grade 316 stainless steel) I secured it using a stainless steel washer and a Nylock nut. At this stage the nut was only nipped up and not fully tightened.
5. With one bolt in place I drilled the hole diametrically opposite and inserted another bolt, continuing this process until all the bolts were installed.
6. Once all the bolts were installed I went around them again fully tightening one and then the one diametrically opposite it.

This hatch is one of two that I have installed in Tra Bhui, the other being in the side of the forward buoyancy tank to allow access to the nuts on the bolts which secure the anchor mount.