Fiberglass Laminations for Strength and Fairing

[hwsiii]

In looking at the the PG25 for use in rough water and maximum rigidity in all conditions I have considered using double bias +-45/45 as one layer and 0/90 degree biax for another. I am hoping that by using this schedule I will have strong longitudinal strength from the 0/90 and latitudinal strength from the double bias. I am planning on using this on the bottom as well as on the inside bottom before installing the stringers and frames. I believe that I will increase the structural strength as well as the rigidity of the boat and add strength to the monocoque structure for many carefree years of enjoyment. At times on the Gulf we have very short period rough water that are not ground swells. If I am wrong in my assumptions please tell me, as I see this as an enhancement to the longevity of the boat by having a stronger hull with less movement in the structure itself thus less stress to the hull.


HWS

[TomW]

There is really no need for this. If you want put a double layer of biax on the outside bottom. Jacque builds into his boats a safty margin based on his experience as a designer at Cigarette and Pusuit. They can more than take on anything you will encounter for years and years to come. The extra fiberglass your proposing just adds unnecessary weight without doing what you want.

Adding fiberglass is not all it's cracked up its to be. If you really want to strenthen the hull add partial frames between the frames in the design, especially the last 6-10 ft, also up the sides to the bow. These add less weigt than the fg that you propose and will give you a very stiff boat.

Tom

[tech_support]

First of all, the lamination schedule given in the plans is more than adequate.

Plywood has stiffness in 0/90.

If you insist on using more glass, just use another layer of 45/45, or a layer of woven cloth. Either way its overkill and will ad unnecessary weight and expense to the boat.

Tom is correct, stiffeners or half frames will give more stiffness to the hull, but again its completely unnecessary

Build yourself a "v" section of the boat use two pieces of 3/8", 2 layers of tape each side of the joint then baix on both sides - try to flex it and then decide if you want to add more glass

[hwsiii]

That answers my question 100%. I knew that I would gwt the right answer by asking. Thank you Tom and Joel, I did not want to overbuild, just trying to make sure I do the best job possible.


Thank you,
H W Slater

[TomW]

HW some of us have put a double layer of Fg on the bottom. We have done this basically as a puncture resistamt llayer. Not as as a stengthening layer.

I don't want to mislead you from my post above, the second layer only adds a certain % of strengthening over the 1st layer. Maybe 75-80%. The real strength comes from the combination of the outside layer of 45/45 biax, the plywood and the inside layer of 45/45 biax.

Stiffening the hull comes from adding the partial frames as I mentioned in my last post and Joel confirmed.

Note these boats are based on interlocking parts that make them extremely strong to start with. Adding the partial frames just makes them evem stronger.

Tom

[jacquesmm]

That answers my question 100%. I knew that I would gwt the right answer by asking.

But why did you assume that we design weak boats?
Ours are designs for amateurs but not designed by amateurs.

[Cracker Larry]

[Spokaloo]

Ours are designs for amateurs but not designed by amateurs.

I think Im going to put that somewhere on Cloud Cap....

My boat gets beaten to death, driven well over its intended speed, sometimes with as many as 8 occupants, well above its suggested speeds. I use a motor that is too large. I carry excessive loads. We use the thing for wakeboarding of all activites! It gets beached on almost every trip out on very steep banks

They are tough as nails, go with the standard lamination schedule.

E

[hwsiii]

Jacques, I thought I was asking a reasonable question in reference to a lamination schedule. I did not assume or imply you designed weak boats, I was just asking if I used the biax as well as double bias, would that not increase the longitudinal strength. I am sorry you took that as an indication that I thought you designed weak vessels, that was not my intention at all. I will be more careful with what I contemplate and ask in the future.


HWS

[TomW]

HW, don't worry about it, ask all the questions you want. That's what the forum is for. Just keep in the back of your mind that all these boats are designed to meet all NMMA requirements and that Jacque has been doing this for a long time. Including stints at Cigarette where boats reached 100mph and Pursuit which are concidered one of the top offshore boats built, before starting this enterprise about 20 years ago.

You can make modifications to your boat and that is not a problem, add anything you want. Just don't change any of the structure that is in the plans. Just what you proposed this time was overkill.

Keep asking questions and we'll help you get the boat you want.

Tom