Leaking Log through hull

[penfold]

Nasa instructions specify that the nut on the hull fitting be done up just over finger tight; people not reading instructions is an entirely human and common trait.

I am aware that Nasa tubes have cracked at the outer flange joint. But why ? Owner overtightening ? Poor plastic moulding ?

 

[Refueler]

Nasa instructions specify that the nut on the hull fitting be done up just over finger tight; people not reading instructions is an entirely human and common trait.

Exactly. But who's going to admit it ?

 

[Fanny Haddock]

How do these things usually fit? I have tube for a paddlewheel transducer in the sole of my fore cabin. The sole is at about 30° so there's no nut & washer like an ordinary through-hull. Will that mean it's a like a flanged pipe that's been fibreglassed in? I've never used it. Thankfully the cap is seemingly gunked on so I can't turn it. Previous owner had no idea what it was for & just thought it was "a drain" (precisely of what to where, I wonder).

It's in a little bit of an awkward place, too close to the locker side, to remove & glass over from the inside I think. Has anyone ever bitten the bullet, removed theirs, & glassed over the hole? It's not a first time learning experience I really want to get into in case it goes wrong, but I'd like to do it.

 

[Refueler]

How do these things usually fit? I have tube for a paddlewheel transducer in the sole of my fore cabin. The sole is at about 30° so there's no nut & washer like an ordinary through-hull. Will that mean it's a like a flanged pipe that's been fibreglassed in? I've never used it. Thankfully the cap is seemingly gunked on so I can't turn it. Previous owner had no idea what it was for & just thought it was "a drain" (precisely of what to where, I wonder).

It's in a little bit of an awkward place, too close to the locker side, to remove & glass over from the inside I think. Has anyone ever bitten the bullet, removed theirs, & glassed over the hole? It's not a first time learning experience I really want to get into in case it goes wrong, but I'd like to do it.

If the tube is located too far fwd - then its liable to be in / out of water when boat pitches etc. so maybe whoever fitted it found it unreliable and removed the sensor.
The recc'd position is away from exterior bumps / fittings on hull and at deepest point .. so as to have it immersed in clean flow water at all times.

Remove and block off ... because of the location below waterline and seriousness if the blocking off fails - I would leave the fitting with its blanking cap ... but if really needed to remove and blank. Then I would be inclined to use two pieces of marine ply and GRP.

I would cut first ply to be a good fit to the hole, but not as deep .... second would be a larger ply plate for inside hull.

Remove and clean up area inside and out ...
Liberally coat the ply insert with resin and press into the hole with ply sitting roughly halfway in the hole.
Before fully set - fill outer part of hole with GRP / Resin mix to slightly less than level - this then leaves enough for finishing with Gelcoat. To keep mix in place - polythene covered scrap pressed in.
Fill inside part of hole level with inner hull - no need for gelcoat here.
Before set - liberally coat second ply piece and place ... applying weight to have it firmly positioned.

Once all set ... complete outer with gelcoat and sand back to level with outer hull ... then prime / antifoul.
Inside boat .. would be good to use glass matt and resin to finish the job and give it strength.

 

[Graham_Wright]

Tip;-
A plastic tomato sauce bottle makes a good bung to stop the fountain.

 

[Refueler]

Decided that I'm going for broke !!

Will drop out the fitting then resin putty it back in ... apply nut on inside ... resin putty around the nut to make sure its sealed then a liberal dose of neat PU on top.

Basically I cannot see reason to not make permanent ... if I ever do have to replace - I'm sure I can lift boat and break the fitting out and then grind back.

 

[Refueler]

Tip;-
A plastic tomato sauce bottle makes a good bung to stop the fountain.

I have a trick for it ...

Unscrew retaining ring ... ease log till the bottom o-ring is just about to come out of tube .. SWAP hands ... so your crap hand is to pull the log out last bit and good hand has blanking cap ready to slap on and screw up.

Just a note to anyone thinking about it : These plastic through hull tubes are NOT suitable to have wood plugs forced into them ...

 

[Refueler]

Lifted ... Log out .. Tube removed ... all cleaned up ... rebedded - refitted ....

On way to YC ..

Pass under 3 bridges ..

Main Port River and Town Quay ..

Waiting lift on YC berth ..

Moving round to lifter ..

In Lifter bay ..

Brought some of channel 'grass' with me ! ..

On the hard ready to work ..

Log and tube out .. scraped and cleaned ..

All done ...

Then it was motor back home ...

 

[Fanny Haddock]

Did I miss something here? Did you put it back or block up the hole in the impressively thick hull?

Was the tube externally flanged & only gunked into place from the outside?

I've done night studies at the University of Youtube on how to fill holes "properly" by grinding them out & building up layers of ever increasing diameters. It looks straightforward enough, the only bit I'm not sure about is how well it works upside down, or whether it slumps downwards while it is wet. I was thinking of using a sheet of acetate or something epoxy doesn't stick to, & a post to hold it on place, then finishing on with a couple of layers from the inside just to clean it up.

Seems to make sense to have the plug wider on the outside as that's where the pressure is coming from.

I like Boatwork Todays presentations. He talks about a 12:1 taper on two sided repairs, & 20 or 24:1 on one side repairs. Also a mix of chop strand & woven matting.

 

[Refueler]

Tube was refitted with GRP Putty applied liberally to the flange and outer part of tube thread ..

Put back in and wood block pressed fully home. Inside - PU glue was liberally applied around the tube so it seeped into any gaps / areas to seaol - then hand nut applied and tightened .....

I missed getting final photos !! I was being pressed for time. But assumed that based on early posts - it would be understood I was rebedding the log tube ...

When she lifts out next winter - I have decided to swap the Echopliot Duo out and fit the new Clipper I have in box ... the Echopilot log has a crack in it and at present has PU glue sealing it ...

It will mean making sure the slightly smaller clipper log tube is well fixed into the hull ... the difference in tubes is less than a millimetre in diameter.

 

[Fanny Haddock]

So it's just a push in, flanged tube, glued or sealed from the outside?

How did you knock it out from the inside, or prise from the outside? I can't remember how mine is fit but I suspect it was factory fitted. BTW, I may have an unsplit paddlewheel unit that looks the same that I'm unlikely to use.

 

[Refueler]

So it's just a push in, flanged tube, glued or sealed from the outside?

How did you knock it out from the inside, or prise from the outside? I can't remember how mine is fit but I suspect it was factory fitted. BTW, I may have an unsplit paddlewheel unit that looks the same that I'm unlikely to use.

Yes its a standard plastic flanged tube fitted from outside ... bedded with sealant and a handnut on inside to secure.

I am interested in replacing the paddlewheel log ... but it Echopilot log is different diameter to others ... and has a multi pin DIN plug on end of cable ... not the co-ax style that Nasa and others use.

Please PM me as I would like to take the replacement further etc. Cheers

Nigel