through hull fittings

[mark_sabin]

Hi gang, anyone got any tips regarding the replacement of through hull fittings. I've got three to do. I assume I just pinch them onto the hull with a smattering of of marine filler on the base plate. Is that about right?

mark

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[oldsaltoz]

G'day Mark,

Thru' hull fitting have flat faces, hulls are curved; so you need to make a flat area on the inside to ensure a good seal.

Some will advise timber or ply soaked in resin to provide some give and movement to help avoid damage if struck.

If the hull is curved at the point you want your fitting (and most are), then some care is needed to provide a good seal on the outside as well as inside.

Start to cut your hole from the inside, this will ensure it's not too close to a bulkhead or other obstructions; now put some tape over the gel coat on the outside and finish drilling your hole.

It is very important that the exposed fibreglass is protected prior to installing the fitting. At least 3 or 4 coats of epoxy resin required.

To provide a nice flat seal inside for the locking nut / seal you can revert to timber / ply. However, I have only ever used fibreglass and epoxy resin to build the seal, and have never had a failure in over 30 years; I must have made an average of 2 a year. No, they were not all in my boat, but I do a lot of fibreglass repairs, alterations, and boat building.

I have assumed your Jeannau is solid glass, if not, let us know and I will post more comments.

Happy sailing...



<hr width=100% size=1> Old Salt Oz /forums/images/icons/cool.gif Growing old is unavoidable. However, growing up is still optional.

 

[Chris_Rayner]

I have an aversion to holes in my nice watertight boat, especially below the waterline. For paddle-wheel logs and water intakes for engines there is no alternative, but for echo-sounders you can mount them inside a glass hull using one of two methods:

The first, and my method of choice, is to construct a small circular dam slightly larger than the sensor. Into this you pour a sufficiency of mixed epoxy resin and then nestle the sensor down into it. facing vertically as best can be arranged. This worked fine in my last boat.

Alternatively, and rather more fussily, you can get a short length of plastic drainpipe which admits the passage of the sensor. This is epoxied to the hull and filled with enough light oil to allow the sensor to be partiallly immersed. The sensor is then dunked into this, and the whole lot topped off with an oil resistant cap. I haven't tried this, so I can't vouch for its efficacy, but it has a certain attraction in that if you ever want to send the sensor for servicing you haven't got to prise it off the bottom of the boat. I think this advantage is more apparent than real.

Best of luck with your drilling holes in your boat.

Chris Rayner

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[Talbot]

Not all echosounders will work with this method. The underwater hull shape makes this system essential for me, and I asked a lot of manufacturers whether there would be any problem. The only one who was happy, and indeed even market an appropriate kit, was Silva. I was replacing an old seafarer which used the mineral oil and worked fine. The downside of mineral oil is that if you get a small leak or a spill, it is very difficult to clean. The silva recommendation was to use fresh water with antifreeze added. This seems to work very well.

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[mark_sabin]

Guys, thanks for the advice. I have no desire to drill more holes in the hull and would rather get a professional to do it if I did (hate to give the wife one on me if a leak was to occur as a result of my DIY failing!!!) I am planning to replace the heads outflow and sink drain. They look as though they have seen better times but there begs the question, How do I tell if I need to replace them? I may be jumping the gun a bit here. I know I need to replace the valve on the heads outflow as its seized.

Old Salt Oz - thanks for your advice. Yes I believe she is only GRP.

mark

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[Guest]

Mineral oil ...... castor oil is the game .... and to clean any leaks - Oven Cleaner .... sprayed on, left for a few minutes, wipe off, fresh-water rinse to remove traces of cleaner and then dried off ....... cleanest surface ready to bond to. In fact after this - you could trickle epoxy / polyester resin around your fitting to seal the leaks !!

The above cleaning routine will set the surface ready to bond your in-hull kit ......

Many advocate using mat and resin to bond the tube to the hull .... I use polyester resing and micro-balloons mixed asa paste so that it completely captures the outer base of the tube. Building up an even wall and slope out to give it strength.


<hr width=100% size=1>Nigel ...
Bilge Keelers get up further ! I came - cos they said was FREE Guinness !
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