Plastic frames for a Halibut Schooner

[Andy H]

I have recently used plastic framing as replacements for original Oak frames and sisters on a 1940 Vancouver Shipyard Halibut schooner. They have served well. Has anyone seen other types of replacement framing used?

[J.Madison]

Halibut schooner? So like 6"x6" sawn oak frames originally? And you replaced those with plastic?


Not all of them I hope....

[peter radclyffe]

is this classified under abs or lloyds

[peter radclyffe]

is it hdpe or alkathene
High-density polyethylene - Wikipedia

[peter radclyffe]

I have recently used plastic framing as replacements for original Oak frames and sisters on a 1940 Vancouver Shipyard Halibut schooner. They have served well. Has anyone seen other types of replacement framing used?

who surveys and insures your boat

[peter radclyffe]

[peter radclyffe]

(17) 23,2 m HDPE CREW BOAT - YouTube

[Breakaway]

There is precedent.



Kevin

[Peerie Maa]

The thing that worries me about that shortcut is this.
Steamed wood is flexible enough to bend and twist into place when hot, but then sets in its new configuration.

Does the plastic take set and stiffen up, or are you left with a flexible hull that works and frets the fays, loosening the structure?

[keith66]

I know people have used plastic for frames but for pitys sake isnt there enough plastic in the oceans already, what happens when the boat reaches the end of its life? dumped or landfill?
I know it might be a way of keeping an old boat going but is it that much cheaper than timber?

[Thad Van Gilder]

I have declined jobs on boats that had been partially reframed with plastic.

I have seen first hand the result of the plastic frames stretching and screws pulling out of the plastic... That is one of the worst methods of boat repair that I have seen... next to the ferrocement shell I saw....

[Pelirrojo]

Pretty sure I know both the boat and the repair very well, in fact if this is the boat I think it is I'm one of the people who did the work. In regards to other methods, No, certainly in my opinion that was the best available repair for the time and place, no good way to put new oak frames in without massively opening up the hull. If this is the boat I think it is, the Plastic was HDPE and fasteners pulled the planks back to proper shape.

Nicholas

[Chris-on-the-Boat]

Plastic has some applications, like exterior rubrails and crab gear chafing. Those pieces are sacrificial and expected to be replaced. As true permanent structure? The plastic expands and contracts differently than the wood around it in reaction to temperature and moisture changes. Over the long run, that means areas of weakness and broken/weakened fasteners. Then there's the wood/HDPE moisture barrier, begging to start rot if the moisture accumulates against the HDPE structure.

While it may have its applications, I wouldn't substitute plastic for wood in structural components of a wood boat.

[Dave Hadfield]

The HDPE I'm familiar with from making sleds has a large expansion-contraction coefficient. Wouldn't that open up the seams if you steamed into warm water?

Not a lot of that in the PNW, I know, but still...

[J.Madison]

Watching my hdpe water tanks deform to the match the support structure over time has convinced me plastic is a poor choice for structural replacements. It just deforms so... plastically....

It's fairly strong, just not stiff at all, and prone to creeping over time.

Seems anywhere hdpe could be used, a laminated stack of wood could also be used for much greater stiffness,