Bonding PVC pipe, to hull, around log to ease removal.

[scruff]

Last year, as usual, my log stopped working after the first couple of weeks due to fouling.

This year however, I intend to remove the log at the end of each sail, and replace with a blanking cap. I would however like to fit a 6" pvc drain pipe vertically around the fitting inside the boat to contain the water which will invariably come in during removal. I know it is not a lot of water, but it runs off to the bilges and is quite hard to get at to dry it off.

The question is however, what would be the best method of bonding said PVC pipe to the hull? would some epoxy do the job or would it be more of a sikaflex job?

Answers on a post card please....

Thank you

 

[VicS]

Not sure that epoxy will stick all that well to pvc.

I think I'd go with the Sikaflex. Check with the Sikaflex users guide or Marine handbook for recommended preparation.

Both available at http://www.bluemoment.com/downloads.html

 

[nigelmercier]

I would use the pipe as a former and build up layers of GRP.

 

[sailorman]

Last year, as usual, my log stopped working after the first couple of weeks due to fouling.

This year however, I intend to remove the log at the end of each sail, and replace with a blanking cap. I would however like to fit a 6" pvc drain pipe vertically around the fitting inside the boat to contain the water which will invariably come in during removal. I know it is not a lot of water, but it runs off to the bilges and is quite hard to get at to dry it off.

The question is however, what would be the best method of bonding said PVC pipe to the hull? would some epoxy do the job or would it be more of a sikaflex job?

Answers on a post card please....

Thank you

I find a sponge efficacious

 

[pvb]

This year however, I intend to remove the log at the end of each sail, and replace with a blanking cap. I would however like to fit a 6" pvc drain pipe vertically around the fitting inside the boat to contain the water which will invariably come in during removal.

You're going to end up with the 6" pipe full of seawater. Putting the transducer back into that won't be very good for it. Why not simply take the transducer out 2 or 3 times a year and antifoul it? It works fine for me.

 

[IJL]

On my previous boat the transducer sat in oil bath that was a bit of plastic plumbing pipe. I sealed it down with a bit of milliput and then surrounded that with plastic padding marine epoxy.

 

[Flossdog]

Could you not dry out somewhere for a tide and do the job in comfort?

 

[sailorman]

Could you not dry out somewhere for a tide and do the job in comfort?

It take but 60 seconds to do & a pint of water ingress

 

[John the kiwi]

Many of the replies don't address your very reasonable question.
I think in there is no problem with what you are aiming to do. I assume you will simply sponge out the contained water rater than have it flow ito the bilges?
The problem is simply the PVC pipe. Cheap? Yes. Available in convenient sizes? yes. Able to be effectively glued to something else? No.

Therefore as suggested, either use the pipe as form to lay up a fibreglass tube or make a box out of epoxy saturated (ply)wood and fix into place with resin and cloth. Whatever you choose, a generous fillet radius of thickened epoxy before laying in the internal cloth will make sponging out easier.
Best of luck.

 

[oldsaltoz]

The ultimate alternative is a log with no moving parts at all, and yes, they are available.
They put a small electrical current into the passing water and measure the decay rate to calculate the speed.

http://www.agiltd.co.uk/marine_instrumentation/agilog_speed_log/

Good luck and fair winds.

 

[oldsaltoz]

Hi Scruff,

You can get PVC to bond to an epoxy resin and cloth, by rapidly heating it with a gas flame, look for small black balls to form on the surface (burnt PVC) and let it cool in air.

The small black deposits melt into the part molten surface and provide a key for bonding.

However, for your application I would be tempted to heat the pipe and form a small flange on the bottom end the conforms to the hull shape, then Sikaflex this into place and glass over the flange.

This should give a bond strong enough to withstand the odd occaton when you lean on the fitting, sloppy sea condition of some tripping on it.

PS can't wait for the comments on the electro log I just posted tongue in cheek.

Good luck and fair winds.

 

[VicS]

PS can't wait for the comments on the electro log I just posted tongue in cheek.

Good luck and fair winds.

I assumed it was April 1st in Oz.


Seafarer used to offer what was IIRC an ultrasonic system back in in the 1970's. Did not work too well I seem to recall and fell by the wayside