Typical Aluminium Construction Details

[Mat-C]

I have some info giving typical construction details for aluminium boats, but it's pretty old, especially these days with CNC cutting so common. Can someone point towards some good reference material?
I'm talking smallish boats - sort of in the 10 metre range

[baeckmo]

What kind of details are you thinking about?

[Landlubber]

Mat,

just because it is old does not make it obsolete...the cutting method of plasma and CAD/CAM is irrelevant, the scantlings are exactly the same whether the cuts are done with plasma, water, gas or grinder......

[Mat-C]

I'm just thinking of construction sections, profiles etc. My understanding is that with CNC cut frames and bulkheads things are done a little differently these days. I gather that stringers would typoically be made from T or L shape extrusions (unless very high). Bulkheads and frames would be cut from flat sheet, to the height of say the deck, with the middle cut out and a flat welded to the edge to produce a T shape there as well.
I tend to be a visual sort of person, so always like to see a drawing / picture to better understand what I'k looking at....

[TollyWally]

A picture's worth a thousand words.

[Joe Petrich]

Mat,

These books may help:

Boatbuilding with Aluminum (2nd edition) by Stephen F. Pollard

Aluminum Boatbuilding by Ernest H. Sims

The Elements of Boat Strength by Dave Gerr

Joe

[Mat-C]

Thanks Joe,
I have Gerr's book, but haven't seen the other two. I'll have to track them down.
Can you tell me, are the construction details - ie, the way the boat is put together - basically the same for a boat of say 15 feet as it would be for a boat say 60ft long? In the smaller boat, would you typically have a number of CNC cut frames / bulkheads, with a series of smaller T or L shaped longitudinals?

[baeckmo]

As Landlubber said, there is nothing specific to the cutting method, so forget about the CNC until you have designed the longs and transverses. Fundamentally, there is no difference in the way the hull structure is designed in different sized hulls; but you will find two "philosophies".

One is reflecting traditional steel building with only transverse framing, sometimes with two longitudinal stiffeners in way of engine carriers. You will see this approach primarily among low speed, displacement hulls.

The alternative is using longitudinals as the primary structure, backed by transverse framing at wider span. This method is almost universal for chine hulls, particularly for planing speeds. As longitudinals you will find extruded L, T and bulb profiles in alu. For transverse, open frames there is a great variety, from those completely cut out of plate with a flat bar welded as a flange, via segments of extruded profiles to combinations of plate and profiles.

Which method we use, depends on a number of factors; personal preferrence, if nesting gives a reasonable scrap percentage, what dimensions are available, production methods a.s.o. Cutting method (plasma, router, saw, waterjet...) and the cutting guidance principle (CNC, light beam, pen plus battens, whatever...) comes late in the decision schedule and has not changed the basic principles of dimensioning!

[Joe Petrich]

As Baeckmo says, the details are basically the same for large and small boats wheter you use longitudinal or transverse framing techniques. NC cutters can cut just about any shape you want so they really don't affect the design process too much, with perhaps the exception that detals which were tedious and time consuming in the past, and so left out of a design, can now be cut efficiently.

The books are available at Amazon.com by the way.

[Mat-C]

Thanks guys - exactly what I wanted to know