Triton-built C-dory Vacuum Bag Weight Savings?

[Darkwater]

Are the Triton C-dories significantly lighter than prior builders due to vacuum bagging the hull and other components? If so, how much weight is saved? (Examples of weight savings by model?) From what I have read, vacuum bagging has significant weight and strength advantages. This would have implications for loading weight capacity and fuel economy.

[tomherrick]

From my experience, I think it's the type and quantity of materials that are used rather than the lamination technique that affects weight. Based on the pictures I've seen, Triton seems to be using vacuum lamination to adhere the core material to the fiberglass hull. That's a great way to ensure lots of even pressure across a broad surface and, in particular, one that is not flat or able to be clamped.

I'd also like to know more about this from more knowledgeable folks.

[starcrafttom]

from what I have read the weight savings from vacuum bagging has to do with the amount of resin used. Far lest resin used in this process. also a far better distribution of the resin Thur the glass.

[Matt Gurnsey]

There's a difference between vacuum bagging and vacuum infusion.

Vacuum bagging probably doesn't save any weight, as the lay up schedule probably remains the same.

Vacuum infusion is a process where the resin is drawn through the glass layup, and requires advanced planning on resin paths to work effectively. Because the resin ratio is calculated to a very tight tolerance this can result in some weight savings.

On a boat the size of a C-Dory, weight savings would probably be in the few hundred pound range, so not real significant. On a larger boat, with a lot of fiberglass pieces, weight savings can be in the few thousand pound range (thing Nordic Tug) whihc is why manufacturers are looking at, and adopting the process. It does add expense to the production of the boat.

[tomherrick]

Tom,

Sounds like you're talking about vacuum infusion. I didn't know Triton was using that technique for hull construction, but it might well result in a higher glass to resin ratio.

Here's the only photo I've seen of vacuum pressure being used at Triton:

[rogerbum]

As Tom mentions, I think the most significant advantage of vacuum bagging during layup is that any voids in the core are filled with resin more efficiently/completely. In particular the kerf in the core that allows it to flex to the shape of the hull is better filled resin. In some hand layup jobs, there can be small channels in the core that do not get completely filled with epoxy. If that happens, those channels provide a place for water to wick from a small penetration in one area of the core to another area of the core. When all the channels are well filled, this is not an issue.

[Darkwater]

Thanks for the informative responses; may be interesting to hear Triton's take on this as well...

[thataway]

Looking at the C Dory Factory posts they refer to vacuum bagging the bottom core--either balsa (C Dory) or foam (Venture). The photos show vacuum bagging. No reference to resin infusion.

I think that the weight savings would be minimal--but that the resin penetration and distribution will be excellent. Vacuum bagging is used often in exotics and with epoxy to get a very light hull. However in the C Dory it appears as if the rest of the hull/deck etc is conventional layup. There would be no reason to decrease the lamination schedule with vacuum bagging, although there will be slightly better resin penetration and slightly less resin, but the same amount of glass.

[sjboysen]

Good responses from all of you. To answer your question there will be minimal weight savings with the vacuum bagging process as it is only used during the bedding of the core and transom.

The molds at this current time are not setup for infusion which by the way we pioneered in our style and size of boat. We started utilizing resin infusion back in 2000-2001, and by 2005 had all of our Sea Sports and Osprey set up for infusion. When I make the shift over to infusion for Cdory, which we will, you will see an even stronger hull being built. It is not necessarily more expensive to produce, actually we noticed a slight cost saving to traditional methods, it is the initial setup of pumps and lines that is more expensive.

In regards to how they are built now or if you have questions about the infusion process please don't hesitate to contact me direct and I will gladly answer any and all.

Sincerely,

Scott

[Catch 22]

I have done a fair bit of vacuum bagging, which is what is shown in that photo. The wieght is reduced because the the process pulls all extra resin out of the part (it ends up in the the breather and peel ply, which is that white cotton looking stuff under the plastic bag.) The wieght savings can be quite a bit too, depending on what other method of constuction you are comparing it too. The strenght is greatly improved do to the removal of any air in the glass/resin. In my opinion a vacuum bagged part is far superior to a non vacuum bagged part.