cutting a hole in the fibreglass hull

[Colin Morley]

Hi all you clever people,

Please can some one give me some good advice?

I want to fit a second self bailer in the outboard well and three bungs in the aft face of the ballast tank of my BayRaider 20.

The question is how do I cut the hull cleanly and accurately with out damaging it. Then how do I seal the edges?

Best wishes,

[Guy Rossey]

Hi Colin,
you probably have read - or should read - this thread: http://www.swallowboats.co.uk/component/option,com_smf/Itemid,28/expv,0/topic,270.0
I followed the good advices in there. For the bailers,  I cut the hole in my GRE hull with the electric device on the picture using the saw under the letter G on the box (no advertisement here!). Very neat. The edges were coated with epoxy before sealing/screwing the bailer onto the hull.
_______________________
Guy
Catchando Bay ( BR #48)

[Graham W]

The Fein Multimaster oscillating tool cuts fine straight edges - or it did for me.  I used the bimetal cutting blade to punch through the correct rectangular shape and then, like Guy, sealed the edges with epoxy.  The boat was new at the time and my heart was in my mouth for most of the time that I was doing the cutting.

The other more difficult and related task that you mention is cutting round holes in the aft wall of the ballast tank to install additional drain plugs (it is worth getting large diameter ones), so that water pours out of the tank and straight down the self bailers with a satisfying gurgling noise.  You need a right angled drill or right angled drill bit for that. Make a small hole first and then use that to centre the drill for a bigger hole using a bimetal hole saw drill bit. Again, seal the edges with epoxy.

Claus (Craic) has published lots of hints on the forum about this and related subjects and it is worth trying to find his contributions.  There are several others as well as the one that Guy mentions, for example http://www.swallowboats.co.uk/component/option,com_smf/Itemid,52/expv,0/topic,341.0

[Craic]

... Claus (Craic) has published lots of hints on the forum about this and related subjects and it is worth trying to find his contributions.  There are several others as well as the one that Guy mentions, for example http://www.swallowboats.co.uk/component/option,com_smf/Itemid,52/expv,0/topic,341.0

Another one is http://www.swallowboats.co.uk/component/option,com_smf/Itemid,28/expv,0/topic,281.0 .

But even with having proper instructions and the right tools to hand it still is a tricky operation which may easily cause damage. I would much rather have the yard do it for all its customers who were sold boats with the old system which was performing poorly from the start and worse than advertised. I heard two weeks ago that the gravity draining system has been adopted by the yard as standard now, but there must still be plenty older boats around which do not have it, and IMHO those customers should not be left alone with it.

[Colin Morley]

Thank you for your help with this.
I have now done it and it worked well with only a little bit of cursing. I marked the hole on the inside and drilled out the corners with about a 6 mm drill. Being careful not to crack the gelcoat on the underside too much. I then cut the hole with the tool mentioned before Fein Multimaster oscillating tool. I borrow this from my son who is a vet and uses it for cutting plasters off horses! I have no idea how the common mariner would get one without great expense. That worked very well. I then gently carved away at the edges with a small Dremel burr so the self bailer fitted snuggly. I then drilled holes for the four retaining screw bolts. That is when the cursing started. The bolts are very short any only just go through the not when tightened up well. With the thin rubber grommet and a good layer of Sikaflex it was difficult to get the bolt through far enough to get the nut on. Any way with the help of my ten year old grandson in the boat and me underneath we managed to get it together.

By the way the bolts need to be countersunk under the boat.

The bailer an Anderon Super mini is not deep enough to hang right through the cut and so sits about 2 mm above the bottom of the boat. I wonder how this affects its performance.

Lastly, Cutting round holes in the aft end of the ballast tank is very difficult because there is not enough room to get an electric or any other drill with a drill or hole cutter attached. I bought a 90 degree chuck but that was too long with the drill attached.  In the end I cut out the holes with a burr attachment on on a flexible drive. Without that I don't know how I would have done it.

So the point of all this is to say that doing these jobs is not as easy as might appear from some of the postings. Dont get me wrong, the postings are terrific but some times need a bit more technical detail.

[Colin Lawson]

Regarding the holes for drain plugs in the back of the ballast tank, I tackled this last week. I also bought a right angled drill chuck, in my case from Lidl, which seems fine (and disturbingly cheap) but also had trouble finding a hole cutter that was short enough. Most have a central drill bit that is too long but if you shop around there are shorter ones that do fit as shown in this link:

http://www.swallowboats.co.uk/component/option,com_smf/Itemid,28/expv,0/topic,281.0

In the end I bought the hole cutter from screw fix but fitted it to a central drill bit that I already had and which was shorter than the correct one. I ended up with the same arrangement as in  the previous link. I was then able to drill out the holes reasonably easily. I sealed the bare fibre glass with epoxy glue then used Sikaflex to glue the drain plug sockets in place (I did not bother with using screws) and this seems to have worked fine.

Next job is to add new Anderson self bailers in the sump (I was going to go for the Anderson mini). I am concerned to hear of the difficulties Colin had with fitting them especially if the result is that the bottom of the bailer is not flush with the hull - this will surely make the bailer less effective?

Colin

[Graham W]

The bailer an Anderon Super mini is not deep enough to hang right through the cut and so sits about 2 mm above the bottom of the boat. I wonder how this affects its performance

Colin,

Somewhere in the bowels of the forum http://www.swallowboats.co.uk/component/option,com_smf/Itemid,28/expv,0/topic,341.0 Claus makes the statement that the externally mounted bailers, like the Mini and New Large, are better at removing water than internally mounted versions like the Super Mini.  The reasons for this I think are as you have pointed out with your Super Mini, the parts that need to protrude into the sea to develop the venturi effect are not ideally placed on the BR because of the thickness of its hull.  The hole for the Mini is smaller than that needed for the Super Mini, and reducing hole sizes is definitely not in my skill set.  So I cut a larger hole and replaced my standard starboard bailer with a New Large, which works very well.  On the port side I installed a Mini, which also works very well.