Customer Reviews

The Elements of Boat Strength: For Builders, Designers, and Owners

5 star:		(16)
4 star:		(6)
3 star:		(2)
2 star:		(2)
1 star:		(1)

 

 

This is a book about the structure of boat hulls that is easy to read and easy to understand. It's primary purpose is to detail the scantling requirements of nearly any small boat hull (10-120 ft) of virtually any material. Gerr has the gift of being able to convey his considerable knowledge to others, and he suceeds admirably with this book. It is well laid out, detailed without being budensome, has a wealth of useful information, and is easy to use. The index is complete. He even includes a short history of, and the advantages/disadvantages, of nearly all boatbuilding materials. If you want to build a reed raft, look elsewhere. Anything more modern than that (with the exception of ferro-cement) this book covers it.

It is always a pleasure to get comments from readers, but I'm afraid that Rick Burner is a mite confused. The Elements Of Boat Strength was specifically written to make it not only possible to determine the scantlings for any boat (from a coasting schooner to a skiff) but to make the calculations required relatively easy. For some reason, Rick's review indicates that Boat Strength doesn't provide you with the information needed calculate the scantlings for traditional boats such as those in books by, say, Howard Chapelle or John Gardner. In fact, Boat Strength provides exactly this information. What's more, you can not only calculate the scantlings for the original construction method but for any modern variant and/or for any other material, from FRP to aluminum.

Marvelously complete treatment of boat design information and the scantling rules needed for the serious boat builder.

Gerr provides building information for every aspect of a wide range of boat types (excluding multihulls, as he notes). He provides the rules and the tables/graphs needed to eliminate complex calculations needed to determine the size and stength that each piece of the boat should be.

A must read for the small boatbuilding shop owner or wannabe designer.

Gerr starts this book with the calculation of a "scantling number." This number is essentially based off the length, width and height of the vessel. He then applies this number to several charts thoughout the book to give "rule of thumb" values on the proper dimensions of the scantlings (hull plating, stiffeners, beams, etc.) for the vessel in question. Overall this book should be useful to the home boat builder. The math in the book is simple and the values obtained from the book seem reasonable for most boats. The books main weakness is that it glosses over the engineering aspects (calculating stresses, etc.).

Elements of Boat Strengh is the most comprehensive and easy to use collection of rules for figuring the size and strength of all type of boats I've seen. It covers almost every boatbuilding material, traditional and modern. The chapters explaining the use of specific materials and methods are worth the cost alone. This is a must read for anyone interested in boats. Highly recommended.

As a person developing a design, I want to put my time into developing hull form, keel, etc., not into hours and hours of calculations about structure which for the moment serve no other purpose than the creation of a plausible weight estimate to be used in Velocity Prediction.

Using Dave Gerr's scantling system, I can produce a good weight estimate, and even a good preliminary construction plan, relatively quickly, and put the rest of my time where it counts the most -- developing the hull form and keel, etc.

As this is the only boat that I have the opportunity to design right now, and it is being done on speculation, there isn't that much time to begin with, and these savings really help. This is especially true in this case because, using Dave Gerr's scantlings, I am not only saving time but also setting the foundation for a good construction plan as well. The book itself focuses on good strong construction, but -- at least for the aluminum construction that I am focusing on -- also considers some options for lightening that structure considerably if that is the desired trade off.

My thanks to Dave Gerr for putting together something that has been needed for a long time.

David J. Fladlien

Dave Gerr seems to be good at a lot of things, but he can't begin to limit himself to just the information the title implies. Yes, he will teach you the elements of boat strength, but he will teach you, in addition, a great deal of valuable - and very interesting - information about wood, fiberglass, polymer and epoxy resins, aluminum, steel, rot and corrosion... with The Elements of Boat Strength you get everything you were promised and more. The technical details are plenty technical, but the more general information is well written and a pleasure to read, and the technical and the general are presented in separate chapters for ease of use. A superb companion to his The Nature of Boats.

Boat Strength covers just about every common building method for boats, from fiberglass to copper-nickel (copper-nickel?). It is quite easy to read for those with a slight technical bent. The many graphs and formulas allow easy determination of the proper scantlings for any particular boat, BUT... it covers only one system of scantlings (as Mr. Gerr points out in his introduction). If you enjoy reading authors like Howard Chapelle or John Gardner (the boat builder, not the author of thrillers) you will be left scratching your head. When they describe the construction of a particular boat you might wonder how the scantlings they used can be calculated from Mr. Gerr's rules. A hint-they cannot. The other disappointment is in a total lack of discussion of the theory behind the rules. Still, it is fun reading and very informative.

I read rather sketchy article on Coyote II in Weston Farmer's book From My Old Boatshop. He had drawings & scantlings for a low-power, low resistance launch. He specified strip built, and that is what I'd like to do.

However, he had the frames on 6" centers and other construction details of a pre-epoxy, pre-glass era. I wanted to find out what I could do with modern materials.

When I entered the Farmer's construction specs into Mr. Gerr's formulas, I came up with much bigger scantlings from Gerr than Farmer. So much so that I could not get the engine entirely inside the boat. Farmer was a Naval Architect, so I have to assume he knew what he was doing.

I'm a real newby with boat construction, so I have no context in which to make a judgement.

Although Mr. Gerr likes the strip-construction method, I don't think he allowed entirely for it's efficiencies once he got past the bare hull. The floors, stringers and engine beds seem way out of proportion.

I am going to go through my Excel worksheet again and see if I made a mistake. If not, I may send Mr. Gerr Mr. Farmer's drawings and my calculations, and see if he will take a commission to reconcile the two. It's a great boat and a great book, so it would be nice if one could help with the other.

As a degreed aerospace engineer, I've used the formula's in this book to easily calculate the scantlings for aluminum hulls from 14' to 30' in length, without exhaustive structural calculations or the need for finite element analysis software. Properly applied, you can build your boat with confidence that it will perform safely in the operating limits described. Are there other ways to calculate scantlings? Absolutely! But if you want "rule of thumb" formulas that are reliable when confined within the operating envelope, this is the way to go. I've plugged the equations and operating parameters into an excel spreadsheet that gives me all the scantling dimensions needed when entering the length, width and depth of the hull. Previous reviewers who stated the subject matter is "wide but shallow" didn't understand what they were reading. If you want to design a boat from scratch and will read and digest the material, this book is a bargain.