Replacing a thru hull on a Newport 30 mk 3

[bil1215]

Hello,
I am currently attempting to replace a thru hull on my Newport 30 it was damaged while removing the old plastic gate valve. This is my first attempt doing this type of job. All thru hull replacement videos I’ve seen online show the thru hull sticking out of the bottom of the boat. Mine however is glassed over so there is no exposed bronze under the water line.
i have sanded back the outer layers of my hull to expose the bronze of the Thru hull
and I’m unsure of the proper technique to complete this job. I was thinking of filling back in the layers I removed then installing the thru hull so that it sits on the outside of the hull, or should I fiberglass it into the hull how the original was installed?
Any advice would be greatly appreciated thanks

 

[dLj]

That's a new one for me. I've never seen a thru hull glassed in like that. I think I'd reinstall on the outside instead of burying it back into fiberglass. Would make for an easier job to replace in the future if ever needed. But really, it's up to you.

dj

 

[dlochner]

Some through hulls are mushroom types and some are flared and sit flush with the hull. The flared ones are sometimes set a bit below the hull surface and then faired into the hull with fairing compound.

Here's an example of a flush mount fitting.

NPS NPT Combo Flush Thru Hull | GROCO

NPS NPT Combo Flush Thru Hull | GROCO

www.groco.net

 

[bil1215]

Some through hulls are mushroom types and some are flared and sit flush with the hull. The flared ones are sometimes set a bit below the hull surface and then faired into the hull with fairing compound.

Here's an example of a flush mount fitting.

NPS NPT Combo Flush Thru Hull | GROCO

NPS NPT Combo Flush Thru Hull | GROCO

www.groco.net

Oh wow, I didn’t know about this style. I’m guessing that is what is on mine, I already bought the flange style so I think I’m going to fill in the glass and gel coat and use the one I have. Any advice on accomplishing this? Or is it simply just layer on the fiberglass then gel coat and install the thru hull
thank you for your help

 

[dlochner]

More or less you have the process down. Take a look at the West System website. There is a free repair manual you can down load that will have more precise instructions.

 

[bil1215]

Thanks for the help I was concerned that this was some kind of terrible repair done before I owned the boat, and the nightmare was just beginning lol. Hopefully this repair goes smoothly. I will update with pictures as I push forward
Thanks again

 

[Tally Ho]

Not quite sure what is going on with the glass to the right of the thru hull…looks pretty gnarly… once you get the thru hull out, you should grind that out a bit and reglass to make sure it is solid.

And there is some sort of void on the left edge too.


Greg

 

[bil1215]

Not quite sure what is going on with the glass to the right of the thru hull…looks pretty gnarly… once you get the thru hull out, you should grind that out a bit and reglass to make sure it is solid.

And there is some sort of void on the left edge too.


Greg

Hi,
Yes that is my plan. Those voids opened up as I was sanding I hope it was just a manufacturing defect. It was dry when it opened up.
my plan after removing the thru hull and grinding down a bevel 12:1 is to redrill a new hole formy thru hull. My question with this is,can I drill thru the repair and have it be structurally safe? Or should I find another spot to relocate the thru hull

 

[bil1215]

Hi sorry my mind was racing through thoughts as I was typing. I mean after removal of the thru hull then grinding the bevel and reglassing, do you think that area will be strong enough to support the new thru hull?

 

[dlochner]

Hi sorry my mind was racing through thoughts as I was typing. I mean after removal of the thru hull then grinding the bevel and reglassing, do you think that area will be strong enough to support the new thru hull?

With a 12:1 bevel laid up properly and with the right glass, yes you can put the through hull back in the same place.

 

[bil1215]

Hi sorry my mind was racing through thoughts as I was typing. I mean after removal of the thru hull then grinding the bevel and reglassing, do you think that area will be strong enough to support the new thru hull?

With a 12:1 bevel laid up properly and with the right glass, yes you can put the through hull back in the same place.

From what I’ve research i should use biaxial cloth layered between strand mat in alternating layers. I hope it will come out the way I’m seeing in my mind lol

 

[dlochner]

From what I’ve research i should use biaxial cloth layered between strand mat in alternating layers. I hope it will come out the way I’m seeing in my mind lol

Be careful of using mat. Most mat is not all that compatible with epoxy. Mat is held together with a glue that that will dissolve in styrene, the solvent in polyester resin. This allows for a lower resin to glass ratio. Epoxy will not dissolve the glue so it is much more difficult to properly saturate the cloth which leads to a high resin to glass ratio, the resulting lay up is heavy and brittle.

1708 is a combination glass, biaxial cloth sewn to mat with not adhesives. Works with epoxy and polyester resins. Talk to West System Tech support or Jamestown Distributors tech support for other options.

 

[bil1215]

Ok thanks a lot I will reach out to them for advice. I appreciate the info 1708 sounds like the stuff I’ll need