[colemj]

Every street light in your town is bolted into helicoils or is a burial pole leaning.
Thread inserts in all industries are common. Your cell phone prolly has 3.
I think you just like to get angry.
Poly carb will bond to the hull with its alike Epoxy. The receiving hole will equal cast aluminum without the possibility of corrosion.
The 3D society is way friendly and patient that you imply.
In software the insert would cost 2.40 Canadian if the hull is 3” thick. Likely it’s 2” in poly carb.
On a group called Cults 3D you can link to 3D artists world wide. You can get a quote for any 3D part in any material. The owner is looking at a Fat 22$ bill plus postage for two inserts in poly carb. ASA and Nylon great marine plastics would not be appropriate.
In every corner of the planet is a 3D printer networked. Its jam packed with leading engineers. The very ppl who build the boat you sail are on it.
18 of these printers are at leading Yacht Clubs. Hinckley Yachts has one in their office. All for private use.
A fibreglass patch is equal to hammering in a cork. Would indicate zero knowledge of fibreglass.

I'm not angry at all, and don't think that any of my postings indicate that.

I didn't question polycarb. Your original suggestion was carbon fiber, which would be a poor choice leading to problems.

Yes, I understand that lights and other things are designed with threaded inserts. However, a threaded insert used as a repair for something not designed with a threaded insert is a compromise over the original design, otherwise it would be designed with an insert. You are comparing apples to oranges in your argument - a designed insert vs a repair using an insert.

The fact that there are a lot of 3D printers around, as well as yacht builders having them, is a non-sequitar. Go ask Hinckley Yachts how they would approach this problem.

A fiberglass patch is far from being equal to hammering in a cork. Else you would have to declare that building the boat itself was compromised. I don't need to detail my fiberglass knowledge and experience, but I'd bet a donut it far exceeds yours.

Mark

 

[Bird Dog]

Den. brain fart on my part: I misread and wasn't thinking of dissimilar metals in contact... fully understand your intent and and aware.

IF I had a 3D printer or easy access to one, in this specific application I agree this would work given this "bushing" would not just fill the thickness of the solid fiberglass hull (I don't recall how thick my Pearson's hull is but it is pretty thick), but also the thickness of the existing backing plate. We are talking a 2" OD, 1" ID "externally threaded bushing" essentially. Epoxied to the hull and backing plate (the threading is a bonus for bonding surface area). Seems pretty straight forward. If made of a non-metal material (which in this case would be the course of action) I don't need to mess with galvanic issues given compatible metals of the transducer's mounting shaft and nut. Add to it that the transducer's back face is larger than the surface area of the original hole. The true mechanical clamping is from the transducer's nut. All this "helicoil" would be doing is filling a ~1/2 void, and in this case the inside would not be threaded. I see internal threading as unnecessary (screwing the transducer into the "helicoil"). Consider how hard it is to remove a transducer that is just slid into a hole with copious amounts of 4200 (or 5200 for the sadists). Have it subsequently bonded to the threads from sealant... no thanks.

Cole, I likewise agree just glassing it over is easy, aside from the added mess. This is such a small area being dealt with, though the work area would be much larger if glassing given the scarf.

I could just as easily glass it over and redrill, but then I'd still have a void in the backing plate. But the counter to that is this isn't under any dynamic load. Just the clamping force of the nut. So I could fill that void with 4200 and would just need to make sure the nut is large enough to have adequate surface contact to the backing plate, but that seems sloppy... So I'd prefer as close tolerances as possible. I'd either have to chisel off the factory installed (assumed epoxied to the the inside of the hull) ply backing plate and install a new one, or still fashion a small bushing/collar to reduce the size of the hole in the backing plate (could just get a piece of epoxy compatible material and make a "ring" and epoxy it into the backing plate's hole...

In the mean time, I ended up just swapping in another B150M because the stars aligned to get the job done when the travel lift was available coincident with my spare time. And just getting the dead B150 out was a chore... But next haul out in a year or two I will pursue this one way or another.

 

[Den]

I'm not angry at all, and don't think that any of my postings indicate that.

I didn't question polycarb. Your original suggestion was carbon fiber, which would be a poor choice leading to problems.

Yes, I understand that lights and other things are designed with threaded inserts. However, a threaded insert used as a repair for something not designed with a threaded insert is a compromise over the original design, otherwise it would be designed with an insert. You are comparing apples to oranges in your argument - a designed insert vs a repair using an insert.

The fact that there are a lot of 3D printers around, as well as yacht builders having them, is a non-sequitar. Go ask Hinckley Yachts how they would approach this problem.

A fiberglass patch is far from being equal to hammering in a cork. Else you would have to declare that building the boat itself was compromised. I don't need to detail my fiberglass knowledge and experience, but I'd bet a donut it far exceeds yours.

Mark

My bad well then you know when you tear something out the fibreglass is weakened. Poly carb is used for formula 1 suspension parts. It handles higher temps than fibreglass, waterproof, UV resistant 10X, oil, has no worries. A 1/2” wall to assure good bonding to a ragged edge. Not a shaft for a rudder or prop but equal too cast aluminum. I don’t like any hole drilled through fibreglass left unsealed. Bedding compound in excess doesn’t cut it.
My senders have threading most their length. Knowing fibreglass structure is a one time thing I only trust Epoxy and nothing else for any repair. Structurally it will be the strongest through hull in the boat. 3D printing used in manufacturing boats use similar methods even inserting metal while printing like the Hanse Yacht 38’ experiment. There are thousands of marine sailboat replacement parts available to print in ASA, Poly Carb, TPU, Nylon and TPE.
At the end of the day I don’t have to sleep on her so no worries.

 

[Bird Dog]

Den, so every hole in your hull is threaded to receive the threads of every through hull (transducers, seacocks, discharge, etc)? Thats an impressive set of taps to do that! Or did I misunderstand you?

 

[Den]

Den, so every hole in your hull is threaded to receive the threads of every through hull (transducers, seacocks, discharge, etc)? Thats an impressive set of taps to do that! Or did I misunderstand you?

Nope wish it was though. Mine are installed just like ones in question.
However I would sleeve any hole I opened to replace an item. Even if it was 2mm wall sleeve.
Through hull is it’s own sleeve but when you grind one out you loose material. The new fitting goes easy.
I print them 1.5 mm larger snug.
A raw unprotected hole is not protected from water migration with extra mounting goo.