fiberglass layup for 17ft fishing boat

Hi

What type of lay-up should I use for a 17ft mod V fishing boat. I don't have Gerrs strength book so I was just wondering if anyone knew this.

Thanks

Keith

 

There's more to it

Your question is like asking "How do I build a 2000 sq ft house?"
Is the boat skinny or wide, used for rowing, a bay boat or an offshore racer? How big of an engine will be installed? Inboard or outboard? With these answers you figure out what forces the boat will see during use. Then, based on your available materials, you build a hull strong enough to withstand these forces.

 

Let me rephrase the question.. What is the typical lay-used for a commercially made 17ft fishing boat such as a sea chaser, boston whaler, or sea pro. It will be used mainly for the bay. If you don't know, then do you have the fiberglass composite allowables and loading environment for various uses. I know how to analyze composites strength. I just don't know what to analyze it too. That is why I asked about the typical lay-up used. My initial question was worded incorrectly. I hope this clarifies my question.

Thanks

flydemon

 

The layup schedule is secured through structural requirements, the results of loading and other studies performed by the design team.

The "typical" production boat layup is chopper (although there are several other methods) with reinforcements as required by the design. These laminates on a craft of your size would run between a 3/16" to 5/16" thick and thicker. Chopper applications, by their nature don't allow very precise application of material, so the laminations are thick. As a rule, engineered structures such as the composite schedule you've asked for are application specific. Without considerably more information about what you are doing any advise would be just a guess.

 

Guess

Use a layer of 4mm coremat on the side skin, cover with 2 layers 24 oz WR with chop in between.
On the bottom use three layers of 24 oz WR with chop in between over a skin coat.
Glass two pieces of 3/4" plywood together with 1 1/2oz chop in between. Sandwich it in between four layers of 24 oz WR for the transom.
Install stringers and bulkheads to divide the bottom panel up into bilge area, fuel tank cavity and a forward compartment. It's nice if the stringers are high enough to support the floor.
If the boat breaks in half, don't call me. If you want a proper laminate schedule and structural design for your boat for a reasonable fee, call me. Happy now?

 

"Happy now?" --- YES. Excellent answer, of course without the sarcasm. Just to make it clear, I am not stupid enough to build a seacraft without putting the proper engineering insight into the design. Just like all structural projects, the initial design is based on whats been done before. Just as you probably know, typical intial lay-ups for composites are based on earlier scantlings. I just wanted to know what a good starting point was. If I were to use graphite instead of fiberglass, I wouldn't be asking these quesitons because I have experience with it for other projects. I do not have experience with fiberglass and cannot find a solid reference on its strength capabilities. I came to this board for help insight, not to be patronized.

flydemon

 

Thin Ice

In these days of ubiquitous litigation you are asking a design professional to go out on a limb. Yes, you should be happy that anyone answered you at all. If you want to know how to do it right go out and get several years experience like we did. I have the ISO 12215 parts 5 & 6 covering design pressures, stresses, scantling determination and structural arrangements open on my desk right now. It covers a full 54 pages. Nobody wants to be responsible for a person being injured or worse because of something they built in their back yard. Pay an engineer to do the calculations.

 

Thin ice

Thanks for the reply. You were very helpful. FYI, I never asked you to go out on a limb. I just asked a question. I didn't ask for you to sign in blood. I am guessing you a formally trained Naval Architect or Enigeer and you do not want to freely pass out engineering knowledge, which I respect. I just wanted to learn a few things. that was all. From now on, if u ever see a post from, please do not reply. Although the info is helpful, it is not worth the drama that it comes with

 

Winer

I usually just read these things but it is time to post.
flydemon, don't be such a winer. You got something for nothing. He got nothing for something. Drama? Hang around a boat yard for awhile if you think this is drama!
Why is it that so many come here for something for free? Free plans needed for a whatever... Do you ask your dentist for a free root canal? Needed: man and backhoe, have no money but need a swimming pool dug. Asking for advice is one thing, free design is another.
Is there no decent "how to" book for the frp boatbuilding novice?

 

oh geez..

When did I ever ask for a free design in my post. All I asked was a typical lay-up used. When did I whine? I am waiting for my Gerr book which I ordered last week from Amazon. That wasn't free yet I didn't whine to Amazon.com. I have all the books from Aurthur Edmunds. That wasn't free. I asked these questions not to get free advice but just something I wanted to know and learn. If this is a professional only website then this is my bad and I am viewing the wrong board.........

 

I am whining again

"I usually just read these things but it is time to post"

So you just read the posts. This is your one and only post. Its nice to know you are a big contributor to this board.

Talk about gettng something for nothing. At least I buy my books. You are probably one of those guys who go to a book store and just read the magazines and never buy anything.

 

So, now that's out of the way and everybody has said his piece.
I'd like to bring some positive energy back to this discussion.

Keith, is there anything else we can help you with? Design details for floor, stringers, deck joints, just let me know and I'll see what I can do.

Peter

 

thankyou and my apology for the negative energy

Peter

Thanks. Maybe I overeacted or read into the original reply a little too much and took it too personal. I would like to thankyou for the last post. It was really calming and comforting. As for member "derekseleski", thankyou for the information and help you have provided. Hopefully, we can get past this. I should've not taken your post so personally. I apologize for that.

Keith

 

Just an expression

Actually in my home the phrase is "happier?" This assumes that you are already happy and assistance made you happier. I didn't mean to tee you off and will be more careful in the future. Let's get back to the business of getting people into boats and boats on the water.