Dave Gerr’s formulas in a spreadsheet

[miguel noguera]

Hy, ya’ll.

The weirdest thing happened to me on the first of August. (My birthday, by the way).

Went to a flea market or bazaar or whatever you want to call it, this in Tijuana, México, looking for a fishing reel and, among a bunch of fishing stuff, was a pile of books.

Browsing the covers, I saw a boat design drawing. Reading the title I almost fell on my rear end! It was “THE ELEMENTS OF BOAT STRENGTH FOR BUILDERS DESIGNERS AND OWNERS” By Dave Gerr!

First, let me tell you guys something. we don’t have those kind of books here. I almost gave up looking for a copy of this book about a year ago.

Reading online I came to knowledge that Dave Gerr is the naval Prometheus of sorts, bringing the precious hi tech naval engineering information down to us, the boat design illiterates like me.

Since luck had a VERY BIG influence in me finding this book i felt compelled to give back in some way; so I went to work on the one thing that I know a lot of amateur boat builders are looking: An easy way of knowing the scantlings of their projects.

Let me tell you something. THIS SPREADSHEET IS NOT COMPLETE (So far I calculated Imperial measurements only) but gives the starting point on knowing how thick the FRP skin of your boat will be and where the reinforcements for support and other things will go.

Remember. THIS IS AN EXPERIMENT and, as Dave Gerr states in his book, ALWAYS LOOK FOR PROFESSIONAL ADVICE REGARDING THE DETAILS OF YOUR BUILD. FOR YOUR OWN SAFETY AND OF THOSE AROUND YOU

But, if you are looking at this as an informative way of knowing a little bit more about what your design will be and be able to have a little bit more info to input in DelftShip’s Lightship data, this is for you.

Oh! And thanks for this amazing design program that DelftShip is. Been flowing this since it was named FreeShip!

Attachments:

• DaveGerrSpreadsheet.xlsx

[Stephen West]

🙂 I also have the book and put together a spreadsheet, though I think yours is better. If anyone has any questions as to size of frames, thickness of hull or any other scant links found on a boat it’s in this book, and probably on this spreadsheet. Thanks

[John R. Coil]

Necroposter Alert!

Did a search on “scantlings” and this was what came up. I too have this very nice book but am interested in scantlings for wooden boats. In particular I like the notion of fiddling with the siding and molding of framing dimensions to arrive at something that can be cut from commonly available lumber. For example, by playing around with low-profile frames a boat with a Sn of 1.6 can get by with 1.75″ molding x 3.5″ siding (24″ on-center) that can be cut from easily obtained 4×4 (3.5″ square actual) DF posts and still not seem to break his scantling rules for frame construction (a quick look-see at Lowes and locally available post showed a pleasantly high percentage with the grain in a favorable alignment, not even close to a majority but also far from rare).

But what I’m really wondering is if anyone has ever seen or heard tell of a system of scantling rules for “instant boats”?

[Author]

Posts