Hand Laid Vs. Chopped

[bigD1031]

Hey all, have yet another question.............

What is everyones opinion on hand laid fiberglass vs. chopped fiberglass hulls? I know a lot of peoples opinions differ but why? Is there any way when you look at a hull that you can tell if it used a hand laid + chopped construction? Looking into the boat I am considering buying I called the company and they said they used both on their hulls.

Thanks for the info.

D

 

[steelespike]

Re: Hand Laid Vs. Chopped

I'm not a fiberglass expert but as I understand it choppers are not as strong as hand laid and are more difficult to repair.
This is only a guess but I would think a hand laid boat would have a descernable woven pattern visable in some areas.Not just in reforced sections.I'm sure someone will be along with more specific info.

 

[tommays]

Re: Hand Laid Vs. Chopped

I have owned and old chopper gun sportcraft tri and it did not fall apart BUT i have also owned a Loyds approved hand laid/balsa cored SailBoat


There was a very LARGE difference in quality yet both boats worked perfect in there intended tasks



Tommays

 

[Chris1956]

Re: Hand Laid Vs. Chopped

The handlayed fiberglass results in long strands of fiberglass versus short (1/2") strands of glass which is stuck together w/resin. Think of the analogy of regular plywood versus particle or oriented strand plywood. The particle board will snap significantly easier than the regular plywood. The OSB is somewhere in between.

Now you could likely make a chopped glass boat as strong as a hand layed one, but it would have to be significantly heavier.

 

[Solittle]

Re: Hand Laid Vs. Chopped

Many boats will have both methods used in their construction. Chopper guns are typically used for other than hull parts where strength is not the main consideration. Chopper layed fiberglass requires significantly less labor to apply. Some manufacturer's of small inexpensive boats wil use the chopper gun for the hull as well. Again it is a cost thing.

 

[ondarvr]

Re: Hand Laid Vs. Chopped

The vast majority of hulls are made with both methods, the skin coat is chopped, after it cures another light layer of chop is layed down and then roving or stiched products are put in place (hand layed). This may be done several times until the hull is the correct thickness. I don't know of any hulls that are currently chop only and while a few companies have made them that way, it wasn't that many.

Not many companies use all hand layed glass, as the cost is higher and the results are about in the finished product.

Some of newer methods of production use all hand layed glass, but it's a completely different method that few boat builders use for this size boat yet.

 

[BillP]

Re: Hand Laid Vs. Chopped

Mat and chop are basically the same. They have random fibers in all directions that give even strength and stiffness. One is on a roll and the other done by spraying "chopped" strands. Both give the same results but...mat is a consistant and uniform layer needing less skill to apply and chop from a gun depends highly on operator skill. Some chopper gun operators use a red colored tracer strand in the glass that helps them see the thickness easier. They also use red colored catalyst to let them know the gun is spraying it at all times. Standard glass strands and clear catalyst is way more difficult to judge when using a chopper gun. Boat mfg still uses mat or chopper alternating with woven roven to achieve the best properties so don't worry about it.

 

[Texasmark]

Re: Hand Laid Vs. Chopped

I am not a glass expert either but I have had numerous glass boats and have worked with glass on different projects, both mat and woven roving.

I agree that mat is chopped up pieces arranged in random directions, rolled out to a prescribed thickness and put on a roll.

Chop is the same but blown in with the depth controlled by how long the chopper gun stays in one spot.

Then there is woven roving. Woven roving is woven like you would weave an Easter basket. It's made of long fibers and therein lies it's strength. Additinally it comes in different weaves and weights.

Different mfgrs use some or all of the above as there are merits to all of them.

I think the worst boat I bought was a 16' Chrysler Sports Fury back in '71. I bought that boat new and had it boat for 1 year and managed to punch 2 holes in it. Never did that before on any boat and haven't since. I know the deck was chopped and not much of that. Don't remember on the hull but I did manage to punch a hole in the bow where the trailer rubber bow chock touches it.

Was going to buy a used MFG once and on the test run as I went over the waves you could see the floor and the hull moving in different directions at the seam [junction of edge of deck (you walk on) to hull] on the port side just aft of the rear of the front deck. Looked like chopped glass to me where the failure existed.

Best boat was a Ranger and I don't think I saw any chopped glass in that boat. I had that boat to 55 mph and airborne more than once and when it came down it was just a "thud". Solid as a rock. Second was a Caravelle. I know it had a lot of hand layment in it but not sure (bought it new in '72) if it was all hand laid.....don't remember. Never had it airborne, but on big waves it just cut right through them.

A lot of times you can see the type of glass if you look at the sides of the boat under the gunnel. Both types are easily recognized.

What you can't tell is how thick the hull is, but you can beat on it with your fist and get a good idea as to how sturd it is. When you hit a thin hull that isn't supported you know it; same with a thick, well supported one.

Personal experience has been with light boats and heavy boats. Just like in a car, the weight makes for a much smoother ride, especially when coupled with a good V hull; at least V in the bow (semi-V). The Chrysler was a light boat, shallow V tri-hull and it showed. The Ranger and Caravelle had the deeper V and the weight and the ride was correspondingly better. Ranger was the best as it had the V all the way to the stern with a pad and had lifting strakes.

With all that said, what baffles me is how you can take glass and form it into something as strong as woven roving on a boat; take it out on the water, pound it to pieces and it stay intact. That just blows my mind.

My 2c,

Mark

 

[BillP]

Re: Hand Laid Vs. Chopped

What would also evidently blow your mind is how strong mat really is and why its used in boat construction. Make two test panels 24"x24"...one layer of 1.5 oz mat and the other one layer of cloth as close to 13.5 oz as you can get. Now bend, twist, hammer, stomp on, whatever you can do to break them.

 

[scoutabout]

Re: Hand Laid Vs. Chopped

What would also evidently blow your mind is how strong mat really is...

Certainly Scout makes a lot of their hand laid processes in terms of strength. From their own modest literature...​

"Scout hand lays every part of every boat built (no chopper guns!) Hand laying our boats makes them much stronger and more structurally sound than the competition.
Every Scout is built to a laminate schedule (using premium, multi-directional glass laminate), meaning that each piece of fiberglass is cut from a template, coded, and hand-laid the same way every time. Building a boat to a laminate schedule with hand-laid fiberglass allows Scout to control and easily replicate each boat's performance, strength, weight, and draft ensuring the highest quality for every model that leaves the factory floor."​

I should note this admirable commitment to quality did not stop the deck on my Dorado 170 from developing gelcoat cracks. Admitedly, I bought the boat used and don't know how it was treated before it got into my hands. It must be a relatively rare occurance for, as I noted in a previous thread, the company has agreed to split the cost of repair even though the boat is out of warranty. It was actually their idea. I just went in for a quote to repair it.

That kind of attitude goes a long way to getting you customers for life, no matter how you build your boats!​