Questioning The Infusion Of 33¨boats

I am involved in the construction of a 33 feet sportfishing boat which we plan on infusing, but a new “doubt ghost” has appeared: I have always wondered how come that some American boat manufacturers insisted on hand laminating their boats instead of infusing them, and found some peace of mind when was told that most manufacturers have old moulds that do not have the necessary wide flange for infusion puposes and do not want to modify them for the purpose of infusion.

And then I found this interview made to the owner and founder of Yellowfin Boats. I have to say that this man started his very successful company around the year 2000 and has made quite a high number of boats, I would say that around 300 or more, so the man must know what he is doing, and no doubt that with his production volume, resin brands must provide him with the very best assessment and knowledge of techniques and best products.


To make the story short, the man Wylie Nagler says that he does NOT infuse his larger moldels 30-42 feet because boats of this size need an amount of reinforcement that when overlapped at the corners with the double thickness that unavoidably takes place, the differential heat generated distorts the pieces (mainly hulls)

He does infuse his smaller models and says he would like to infuse the larger models as well but that the necessary repairs needed to restore the heat produced surface distortions makes infusing the larger boats NOT WORTH

Here is an extract of the interview:

Q: You build your smaller boats with resin infusion. Why are the boats more than 24 feet hand-laid?
A: We would love to infuse everything. When you get into the bigger boats, the problem with resin infusion is they haven’t developed a resin that can really control the heat transfer in gelcoated boats. The overlapping fiberglass areas of larger boats will show signs of heat. If you’re painting, you fair the overlapping areas and paint it. With a gelcoated boat, you’re building up so many laminates and you have so many overlaps that when the resin gets sucked in there and starts to cure, the temperature increases dramatically. That creates cosmetic issues when it comes out of the mold — heat buildup basically, and the heat buildup will be in the chines and the strakes and wherever you overlap. If every part of your boat is coming out of the mold distorted because of the heat and you have to go refair it and paint it, that creates an extra expense. You don’t have to touch a hand-laid boat that comes out of the mold. With smaller boats like bay boats, you don’t have a ton of overlapping areas because it doesn’t take the loads that an offshore boat does, so the heat issue and cosmetic issues are not issues.

Q: What are the benefits of building with resin infusion?
A: It’s by far a better way to build a boat. It takes a lot of human error out of the build process. The biggest benefit of infusing, outside of the quality of product, is the human factor — it’s so much better for your employees. They’re not working in the resin all day, every day. You skin it out and everything is going in dry. And you’re loading the resin into a bucket and turning on a switch, so you’re basically working with a clipboard monitoring what you’re doing. It takes less time. We can build an infused boat quicker than we can if we hand-lay it. The labor load changes. Let’s say it takes five guys to build the hull in hand-laid sandwich construction. We can take those same five guys that day, have them skin the boat out and then break it down to three guys for the next two days and infuse the boat. And then we can take the other two guys and put them somewhere else. It’s more efficient.


So I would like to know if by using a thicker vinylester skin coat and “stepping” the edges of the fiberglass in the overlapping areas the heat distorting problem could be solved.

I am very worried about this because we planned on offering a slightly better boat than average to gain an edge in the market niche due to the benefits of it being a lighter and stronger boat made with less resin, we also wanted to avoid at all cost laminating by hand at least in the larger pieces

So I would like to know if by using a thicker vinylester skin coat and “stepping” the edges of the fiberglass in the overlapping areas the heat distorting problem could be solved combined with the use of a slow reactivity or low exotherm resin.

In this case I would also be interested in knowing wich vinylester resin is the less problematic in regards to heat problems and therefore most suitable for our purpose.

So I would like to know what forum colleagues have to say about this: true or false ?? are there any solutions to overcome this potential problem ??

 

Great subject. I have no large scale experience to contribute, but I had occasion the other day to be reminded how hot a large section of epoxy gets when it is curing.

One of the possible scenarios that might overcome this problems sprang to mind, was a double infusion. Infuse the hull with the 'standard' layers, and then do another infusion of the thicker sections, or, if it seems more economical, hand lay the reinforced areas.

Perhaps more importantly, there are a range of special hi-temp mold materials available these days. They have been discussed in a few threads, and there are pros and cons.

I will be following the contributions here with interest,

 

Exotherm is a problem..

I understood that production builders attack this problem by cooling the molds or using special resins..

Your designer and supplier can educate you on strategies to control heat

www.compositesworld.com/articles/the-evolution-of-infusion

www.compositesworld.com/.../new-infusion-regime-for-superthick-la...

 

I have not done a boat bigger than 35 feet, but certainly had no problems with overlaps and overheating, I guess it is all to do with the specific layup required.
I can understand his comments though, it would be a darn nuisance to have these problems.

 

it should be able to be controlled... many people are infusing much larger and heavier structures than 24ft boats... have a look at teh wind turbine industries methods, they are infusing very heavy laminates and have the process worked out.

Do some research and talk to people, you will find a solution, special resins, cooled molds etc

Do you have any details on the thickness of the heaviest laminate in the layup?

 

I think the problem is not so much the length of the job but massive build up of overlaps, big rotor blades etc have very little overlap or corners that make things nasty.

 

You can infuse just about any size hull, I have customers that infuse yachts that are well over 100', we also have resins that can be infused at over 2.5" thick with no heat issues, even thicker with different types of initiators. It does take a good deal of testing to develop a laminate schedule and resin that will do exactly what you want it to do every time, this relates back to that Human factor, you need to be able to replicate the successful method every time, people have a tough time doing that.
Any infused part that has a gel coat finish can be challenging because as the resin content decreases and the fiber content increases the possibility of print through (surface distortion) increases. Special steps need to taken to help prevent it, sometimes it can be too costly or time consuming to achieve the desired results so builders put it on hold until it makes sense to go that route.

 

Hi to all,

Mr Watson, it took me some time to figure out the possibility of doing a double infusion and you thought of it in a second ¡¡¡, but not only it would be a chore, it may also be expensive due to the expense of consumables, but as you pointed out it seems to be a solution eventhough probably expensive and time consuming.

Mr Landlubber, was your 35 feet boat a sailboat or a motor boat ?? because IMO, sailboats have fewer edges or corner and thus less need of overlaps also, maybe sailboats do not need a hull as strong as is needed for a fast 33 feet sportfishing boat (which is our goal) and this lower tickness may not have the heat related issues

Right now I do not have where I am the data of the final thickness of our hull, but I very much that it would go beyond the one inch thickness anywhere overlapping zones included, so maybe Mr Ondavr, would be so kind as to say wich resins (brand and reference) are used for those high thicknesses

 

Motorboat, like the sports boats here
http://rowellmarine.com.au/results_...Motor Boat&length=all&material=all&price=all#

they were made in a yard owned by the Norwegians.

 

Michael Pierzga, dear fellow countryman, I thought the same, resin suppliers and vendors would surely give Yellowfin boats the very best assesment, but apparently, it has not been the case, maybe because there is no solution for the heat issues, surely boats could be made almost any size, if them coming finished out of the mould is not expected and refinishing fairing the hulls is acceptable which IMHO it is not.

The man owner of Yellowfin surely does like the infusion process or so he says, but apparently (or so he says) boats for offshore use larger than 24 feet are not doable without refinishing and bear in mind that he is the USA, where all technological advances are readily available, particularly for someone like him with such bussiness volume, so whats upp with this ??

 

Mr Landlubber, then it has be doable, but did the norwegians had to refinish and paint the boats or did they come out of the mold already finished with just the need of some polishing whcih is the case whenenever a hull is hand laminated ??

 

No, straight from the mould, immaculate topsides.

Most in dark blue, so they have to be good.

We did paint, but only for owners colour specs.

 

I am talking about this type of boat, quite overpowered and capable of quite high speeds maybe north side of 50 knots, similar to this hulls:

 

Mr Landlubber, do you recall the resin brand and references ??

I have to go now to the shop ..

 

http://www.gurit.com/gurit-sprint.aspx

but it was an older version, this is their latest version.