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Author Topic:   Closed Mold technologies
jimh posted 05-17-2002 09:19 PM ET (US)   Profile for jimh   Send Email to jimh  
Brunswick CEO George Buckley told investment bankers in a 1st-quarter conference call that Brunwick's SEARAY division was about to begin using closed-mold techniques for producing boats.

The closed-mold technique offers big improvements in environmental impact, better quality control, and other manufacturing benefits (lower costs?).

Buckley forecast that more boat building would be moving to this technique, which would be beneficial for Brusnswick as it would increase the cost of entry into the boat building market for potential competitors.

The higher captial costs, tooling, design, and development needed to produce boats using closed-mold techniques will inhibit competitors from entering the market, while at the same time offering improved margins and higher profits for Brunswick.

Buckley explained that the small boat business has traditionally been one with very small margins, but this technology offered a chance to reduce production costs while improving quality of product, thereby increasing marings and profit in small boat production.

While Buckley did not mention Boston Whaler specifically, a close-mold technique would appear to be a natural adaptation for building a Whaler unibond hull.

PMUCCIOLO posted 05-19-2002 05:51 AM ET (US)     Profile for PMUCCIOLO    

Kindly educate me [us]. What is "closed mold" boatbuilding?


bigz posted 05-19-2002 07:33 AM ET (US)     Profile for bigz    

Let me dispel the Brunswick news first. Genmar has since last year had online a highly state of the art close molding plant in Little Falls, MN where Larsen and Glastron boats are produced. In fact Genmar has really for a number of years been at the fore front in the development for boat building with this technique.

Basically the technique is the use of a enclosed mold (male and female are sealed tightly together via for lack of a better term clamps with a core left between them). This process commonly know in the industry as Genmars VEC (virtual engineered composites) closed mold system infuses or injects the materials into the mold and then is allowed to cure (in most cases this curing is done by baking in an oven or external heating of the mold). When cured the molds are separated and out pops a shiny new hull. The Japanese and the Dutch are also developing systems which could be very competitive to the Genmar method.

For large hulls the industry gurus feel that what will occur is that there will be a few very large contract operations offering the smaller custom or semi-custom builders the service of providing their own hull designs using this technique since most won't be able to afford the cost associated in building a plant to produce just limited numbers of hulls per year. Of course what is driving the transition is the EPA regulations which will place a tremendous cost burden on builders using the tried and true open mold due to the emission standards which are gradually being phased in. Consequently some are already turning to vacuum bag molding techniques which to a degree but not as much as closed mold infusion reduce emissions principally of styrene.

BW could make their hull and top side using this molding method, then as they do now clamp the two together and inject the foam as JimH is suggesting.

Anyway this was just a simple explanation, though I hope it gives you a rough idea of the technique.

Professional Boat Builder published by Tauton press (of Professional Home Builder/Fine Wood Working fame) has over the past number of years discussed this technique and a few others which in the long run will prove to be the methods of choice not only to reduce emissions but more importantly produce cost savings and take out many of the faults inherent to traditional open mold production.

Tom W Clark posted 05-19-2002 11:23 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
I believe Hinckley uses a closed mold process called SCRIMP or something like that. Genmar has had their own in production for a while as bigz points out.

I was reading a very interesting article on the Genmar VEC (Virtual Engineered Composites) which described the process. It sounded like a proprietary process unique to Genmar. If Brunswick has their own in the works it must take some different form.

Genmar has something like 30 million invested in their system and is now cranking out boats in Minnesota using the system.

The molds are immersed in water both to support the pressure as well as to control the heat of the molds. Ovens are not used.

A conventionally laid up hull might sit in its mold for hours while the VEC system can produce a hull in 40 minutes. The hull that comes out of the closed mold is far more precisely controlled as to its shape and weight.

At the Little Falls plant where Glastrons are built they say even the best lay up teams can produce 17’ hulls conventionally that vary as much as 50 lbs. (This is an interesting observation in terms of estimating how heavy one’s Whaler hull should be) while the VEC produced hulls vary maybe 1 pound!

When the hull comes out of the mold it is so precisely shaped that a multi-axis computer controlled router trims all the edges and holes are drilled in the hull for various mountings to 1/1200” accuracy.

The quality of the fiberglass itself is different than a conventional hull as well. It is perfectly smooth on the inside as well as the outside, no additional finishing is required.

Because the fiberglass is computer controlled in the mold through about 500 parameters the ‘glass itself ends up much stronger. Screws can be tapped into the hull without the use of any backing as well.

This technology is not compatible with the Whaler Unibond process. With a Whaler two conventionally laid up hulls are brought together before they are fully cured and then joined together while foam is poured into the void.

The foam adheres well to both skins because the ‘glass is both rough and still curing. Final curing occurs with the foam in place and the whole hull, skins and foam, cure into one piece.

One would not want to build a Unibond hull with two fully cured skins that are perfectly smooth on the inside with little for the foam to adhere to.

jimh posted 05-19-2002 01:50 PM ET (US)     Profile for jimh  Send Email to jimh     
Thanks to all who provided technical details of the closed mold process.

What strikes me about this change in production technique is the effect it will have on the boat building market. Until now, it has been relatively easy for anyone who had an idea, a few bucks, and some resin to build a small fiberglass hull using the typical female-mold technique. This has allowed for a large number of companies to be in the boat building market, which makes for good competition and creates a very large number of choices for the consummer.

In contrast, if it takes $30-million in tooling to get into the small boat marketplace with a closed mold production facility, this is a much larger barrier to entry than exists now. There are many boat companies that have started with probably less than $100,000 capital and have become successful. That won't be happening in the future.

Perhaps the production process will become somewhat akin to silicon chip fabrication, where chip foundries produce devices for a number of chip design companies (who cannot afford to own or run their own chip fabrication plants).

jimh posted 05-19-2002 01:53 PM ET (US)     Profile for jimh  Send Email to jimh     
In a closed mold technique, how is the resin introduced and how is it directed onto the mold surfaces?
bigz posted 05-19-2002 02:30 PM ET (US)     Profile for bigz    

JimH, depending on the closed mold process it varies, however in general all are forced under high pressure through piping into the mold. This closed system in itself eliminates just about all pollutants from the air.

You mention the future since cold mold and vacuum forming are pretty expensive when it comes to larger hulls, as I mentioned the reasoning goes there will be fewer companies making their own hulls depending instead on a group of large specialized molding operations to produce their designs for them. On the other side of the coin other methods are being developed to over come the emission regulations and some feel that despite the cost companies will devise their own methods to satisfy requirements as the time nears so that you will never see just a hand full of companies controlling the market. Who knows I certainly don't! Just have to wait and see I guess.

Another thing Tom Clark mentions the BW process wouldn't be compatible since the skins would be fully cured and as smooth as glass. I have used two part polyurethane foam poured into the cavities of a perfectly cold smooth fiberglass form and the foam stuck like glue.

I also believe there is no need to have 'hot' curing surfaces to inject foam for it to adhere to the outer and inter skins of the hull. I was not aware BW used uncured surfaces when they poured the foam since they have multi-molds for certain models and these are it appears laid up and wait there turn for the foaming operation.

Maybe one of the fellows or the 'draftsmans' wife can shed some light on this. Someone who has actually watched the foaming process.

OutrageMan posted 05-19-2002 05:08 PM ET (US)     Profile for OutrageMan  Send Email to OutrageMan     
I am not sure about Hinkley, but Pearson is using the SCRIMP technique for its new Ture North 38'.


dfmcintyre posted 05-19-2002 08:15 PM ET (US)     Profile for dfmcintyre  Send Email to dfmcintyre     
Two comments:

The Glastron VEC process, was not developed by them, but by one individual, who's name escapes me. Took him years of work perfecting the system. Wasn't sure until I remembered that it uses water for part of the process. Patent rights were probably bought.

In 1977, we toured the origional Whaler factory, as I've mentioned in previous posts. The line was producing a 17' hull as we went through it. Both hulls were still "fresh" and still in their respective molds (one mold was called (in factory lingo) the turtle, the other, the bathtub), when they lifted the turtle (actually the inner liner) with chainfalls, and rotated it 180 degrees and lowered it into the outer hull mold. Clamped togeather, mixed and poured the foam in.

I can't remember just how fresh or wet the two hulls were, prior to the foaming process, but there were not a bunch of hulls sitting around, waiting for the foam.

We didn't see the 13', squall or 21' lines, they may or may not have been in a seperate building, or might have used the same line, just changed mold sizes when needed.

Keep in mind, that our tour was in September, 1977, and manufacturing procedures may (probably) have changed...


bigz posted 05-20-2002 08:45 AM ET (US)     Profile for bigz    
Thanks Don for the clarification. I will check with CB at BW to find out at exactly what stage they pour today.

Here in order for those interested is the background history of VEC.

Chap posted 05-20-2002 09:17 AM ET (US)     Profile for Chap  Send Email to Chap     
Here is another couple of fine SCRIMP boats.

The Pilot is fitted out nicely.

jameso posted 05-20-2002 09:55 AM ET (US)     Profile for jameso  Send Email to jameso     
Logic Marine in the Carolinas does a Roto-Mold thing with plastic, often though of doing the same then injecting it with a closed cell expanding foam, should be bullet proof.
Tom W Clark posted 05-21-2002 02:06 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Pouring foam into two partially cured skins is an integral part of Whaler’s Unibond process. It is described in most of their literature. No Whaler has ever been produced with cured skins that have been sitting around.

Closed molded skins would require an additional step or treatment to promote adhesion of the foam to the skins. Whaler is not likely to use closed molded skins in their Unibond hulls because of this. Whaler has, however, been working with closed molding for small parts for the last year.

The Brunswick closed mold process is owned by RTM Composites. Genmar initially entered into a joint venture with VEC Technology but now has bought the entire company.

Part of Genmar’s huge investment was the building of the Little Falls plant which has a huge capacity. They say they are only going to build their own boats and not subcontract to other builders but it sounds like they are keeping their options open.

Because of the expense of the tooling, we will see lots of small (like 17’) runabouts built with these technologies. I believe Brunswick’s first hulls will be 18’ bow riders. It is going to pay these corporations to produce huge quantities of similar hulls. It seems natural that Bayliner would make good use of this technology because of this. It seems far less likely that a relatively small builder of quality boats will benefit in the same way.

It will be very long time indeed before we see a 50’ SeaRay built from a closed molded hull. The expense and complications of the tooling for hulls of this size would be enormous.

The E.P.A. may end up forcing small builders to this technology but if they don’t own the process they will be paying someone else, perhaps one of their competitors, a good chunk of change to use it or build the hulls for them.

dfmcintyre posted 05-21-2002 06:47 AM ET (US)     Profile for dfmcintyre  Send Email to dfmcintyre     
Chap -

I like the lines on the 19 and interior. Only one item bothers me, and that because of the color of the leaning post, it makes the unit look aftermarket (which it probably is....). They should have painted it to match the inner hull.


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