I am in the process of restoring a 1988 OUTRAGE 22. Having noticed how the foam can get soaked through the brass drain tubes if they let water in, I went a bit radical with the fix. After removing the brass I basically carved a doughnut shaped cavity by working through the holes of the drain pipes with a self made tool. a bike spoke bent at 90-degrees and attached to the drill.
I then filled the cavity with resin whilst keeping the brass tube in place from the underwater side. The brass tube was covered with vaseline and wrapped in cling film for removal. I let the resin cure, and then I took out the tubing. creating a very robust and perfectly fitting housing for the brass tube. This in turn totally isolates the foam from any unwanted ingress of water from the O-ring, caulk or whatever.
If interested i can post a guide and illustrations to explain the technique in detail.
Through Hull Drains: A New Technique
Through Hull Drains: A New Technique
Last edited by Fenx on Sun Mar 17, 2019 3:29 pm, edited 1 time in total.
Re: Through Hull Drains: A New Technique
The method of forming a resin annulus around the opening for the drain has been mentioned before. Good illustrations of the method would be very useful.
When you say "donut" I think you mean to describe how there is a sealed area of resin at the surface of the tunnel or opening through which the drain tube will pass, and this sealed area will provide a water-tight protection, should any water get past the O-ring seals on each end of the brass tube.
When you say "donut" I think you mean to describe how there is a sealed area of resin at the surface of the tunnel or opening through which the drain tube will pass, and this sealed area will provide a water-tight protection, should any water get past the O-ring seals on each end of the brass tube.
Re: Through Hull Drains: A New Technique
That [intrepretation of the "donut"] is correct: the walls of the annulus being about 3-cm thick, and that is the difference between the external diameter and the internal diameter of the annulus.
I will post some pics and work on a guide as I had to go through some trial and error in the process.
I will post some pics and work on a guide as I had to go through some trial and error in the process.
Re: Through Hull Drains: A New Technique
Draft version. No pics yet.
Step 1 – Prepare the carving tool and carve the hollow space to accomodate the resin. Use a bike spoke to create the carving tool. Cut it at about 15 cm length. The thick and conic part of the spoke is a perfect carving bit. Not only it will carve through the foam but it will be very useful to grind the internal sides of the fiberglass for perfect adhesion of the resin. This is necessary as the foam in these areas has come into contact with salt water in most cases. Bend the thick end at 3 cm (this will provide the radius of your annulus). Attach the bit to a drill or Dremel and remove the foam. Make sure to grind thoroughly the inner-sides of the fiberglass.
Step 2 – Clean. Once grinded blow air in the hollow with a hair dryer to eliminate carved material and dry any moisture. Clean internal fiberglass surfaces with acetone.
Step 3 - Prepare the through hull brass. Use a pre-flanged one on one side. Cover it with Vaseline, wrap around some cling film and add more Vaseline on top of the cling film.
On the flange side add some masking tape, say about 3 rounds offset by a few millimiters to create a tapered thickness. This will be needed to ensure the tube can be depressed into the hull and remain firm.
Add the o-ring for extra sealing. This will sit between the wrapped flange and the hull.
All tubes to be inserted from the bottom of the hull. The top side of the tube will need a lid. I used cork.
Step 4 – Protect the boat from excess resin. Mask the boat side of the holes. Use masking tape to mask a large surface around the holes, boat side. Mask also on top of the hole and use a cutter to get the perfect hole. You don’t want the excess resin to flood your boat, the area should be about a palm large, depending on which through hull you are doing you may need more.
Step 5 – Inection--two persons needed for this. One guy from the hull side will insert the prepared brass almost all the way through. The other guy will inject the resin with a large syringe from the top side (inside the boat). He will need a bowl with the resin as a few doses will be required. As a rule of thumb you will need about 1.5-liters of resin overall. Deep holes such as the ones on the sides of the bow will need about 350-ml each. When filled, push from the bottom and press to ensure the masking tape locks the tube and the o-ring is compressed. Make sure to prepare the resin for one hole at a time or it will be a mess.
Step 6 – Removal and filling. This is a delicate process as you don’t want to ruin the brass. Brass won’t come out easily and you will need to bang it with a hammer. Use a piece of wood to avoid damage to the brass when hitting when the hammer. Best to hit first from the bottom for the initial movement and then work from the top. I used a aluminum tube with thick walls to push the brass out but one can use another bit of brass. All tubes to be removed top to bottom. You will find some cavities left on the top side, as some resin will drop or be absorbed by the foam, check both sides with your finger and just use some filler. Drill with a 1” bit for a perfect fit.
Step 7 – Gel coat. Given that I preferred to use polyester resin (we can debate why), I then gave two layers of gelcoat to the holes.
Step 1 – Prepare the carving tool and carve the hollow space to accomodate the resin. Use a bike spoke to create the carving tool. Cut it at about 15 cm length. The thick and conic part of the spoke is a perfect carving bit. Not only it will carve through the foam but it will be very useful to grind the internal sides of the fiberglass for perfect adhesion of the resin. This is necessary as the foam in these areas has come into contact with salt water in most cases. Bend the thick end at 3 cm (this will provide the radius of your annulus). Attach the bit to a drill or Dremel and remove the foam. Make sure to grind thoroughly the inner-sides of the fiberglass.
Step 2 – Clean. Once grinded blow air in the hollow with a hair dryer to eliminate carved material and dry any moisture. Clean internal fiberglass surfaces with acetone.
Step 3 - Prepare the through hull brass. Use a pre-flanged one on one side. Cover it with Vaseline, wrap around some cling film and add more Vaseline on top of the cling film.
On the flange side add some masking tape, say about 3 rounds offset by a few millimiters to create a tapered thickness. This will be needed to ensure the tube can be depressed into the hull and remain firm.
Add the o-ring for extra sealing. This will sit between the wrapped flange and the hull.
All tubes to be inserted from the bottom of the hull. The top side of the tube will need a lid. I used cork.
Step 4 – Protect the boat from excess resin. Mask the boat side of the holes. Use masking tape to mask a large surface around the holes, boat side. Mask also on top of the hole and use a cutter to get the perfect hole. You don’t want the excess resin to flood your boat, the area should be about a palm large, depending on which through hull you are doing you may need more.
Step 5 – Inection--two persons needed for this. One guy from the hull side will insert the prepared brass almost all the way through. The other guy will inject the resin with a large syringe from the top side (inside the boat). He will need a bowl with the resin as a few doses will be required. As a rule of thumb you will need about 1.5-liters of resin overall. Deep holes such as the ones on the sides of the bow will need about 350-ml each. When filled, push from the bottom and press to ensure the masking tape locks the tube and the o-ring is compressed. Make sure to prepare the resin for one hole at a time or it will be a mess.
Step 6 – Removal and filling. This is a delicate process as you don’t want to ruin the brass. Brass won’t come out easily and you will need to bang it with a hammer. Use a piece of wood to avoid damage to the brass when hitting when the hammer. Best to hit first from the bottom for the initial movement and then work from the top. I used a aluminum tube with thick walls to push the brass out but one can use another bit of brass. All tubes to be removed top to bottom. You will find some cavities left on the top side, as some resin will drop or be absorbed by the foam, check both sides with your finger and just use some filler. Drill with a 1” bit for a perfect fit.
Step 7 – Gel coat. Given that I preferred to use polyester resin (we can debate why), I then gave two layers of gelcoat to the holes.
Re: Through Hull Drains: A New Technique
I created a guide with illustrations; it can be downloaded from:
https://drive.google.com/open?id=10T-VpM4a-u45Ge0R-zrPFIA58_mtD5wb
https://drive.google.com/open?id=10T-VpM4a-u45Ge0R-zrPFIA58_mtD5wb