Aluminum de25

[Fuzz]

Over the years I have fished several wood boats, glass boats and aluminium ones. Each material has its strong and week points. One that does not get talked about with aluminium is cracking in the weld zones. Fished a high end boat built in Seattle that we spent half the season sowing it back together after each opening. Had two friends whose set net skiff had the transom come out of it and killed both of them. Like all materials it can be good but it not perfect.

[OneWayTraffic]

That reminds me of one of the best quotes from Tolman's book: "I'm too smart to build in glass, and not smart enough to build in Aluminium." I wouldn't even attempt it myself without some serious equipment.

I managed to glue an Aluminium keel strip to my boat easily enough. And there's UHMW on the chines and sides. That should handle much of the heavy beating that I don't plan on giving it.

Anyway here's an example of Gerr specifications for a 29' Aluminium boat. It's a start though 29' is bigger than 25'.

Sn Scantlings – 29-Foot Aluminum
Bottom: 0.25”
Topsides: 0.1875”
Deck: 0.1875”
Bottom Longitudinals: Flat Bar 1.375” x 0.25”, spaced 11.375”
Topsides Longitudinals: Flat Bar 1.25” x 0.25”, spaced 10”
Deck Longitudinals: Flat Bar 1” x 0.25”, spaced 10”
Ring Frames: spaced 29”
Ring Frames Bottom: Web H. 2.875” Web T. 0.25”, Flange W. 2.25”, Flange T. 0.3125”
Ring Frames Side: Web H. 2.25” Web T. 0.25”, Flange W. 2”, Flange T. 0.25”
Deck Beams: Web H. 2.125” Web T. 0.25”, Flange W. 1.5”, Flange T. 0.3125”
Ring Frame Knee Radius: 2.75” min.
CVK: 3” H. x 0.375” T.
Floor Height: 1.75” above to of CVK min.
Engine Bed Girders: Web H. 6.5” Web T. 0.25”, Flange W. 1.875”, Flange T. 0.3125”

Source:
https://www.gerrmarine.com/ELEMENTS_OF_ ... thIBEX.pdf

[BarraMan]

I'd say it's pretty easy to compete against stitch and glue with aluminum. FRP out of a mould is harder to compete with for ride.

I guess we will just have to agree to disagree on that !

[cracked_ribs]

Once you get out of production aluminums and into the small-market high end stuff, it's a different world.

I've been on some metal boats that ate big water as well as anything. You can make a crash-bang bathtub out of it, but you don't have to.

[Rziel]

I have built a stitch and glue small boat vary easy process. But I feel if I built stitch and glue on a larger boat it might be about the same weight. I tend to over build and would likely apply lots of extra glass for toughness and wear resistance. Perhaps I should build light and treat it like a yacht. Not likely maybe ten years down the road.

[OneWayTraffic]

Just how many logs and rocks do you plan to run into? A layer of 1708 instead of 12oz would have a significant reinforcing, and UHMW strips can be glued. I can tell you how if you like.

[BarraMan]

My boat has 3 x layers of 12 oz cloth over the entire external bottom - but with the 3 x layers of overlapping 12 oz tape where the panels join at the keel and the overlapping of the cloth layers, it actually has 9 x layers of 12 oz glass cloth externally over the keel!

[TomW1]

There are many aluminum boats available for sale and use and are quite popular in the Midwest. This is a Tracker 19 deep-v https://www.trackerboats.com/deep-v/tar ... ition.html Not exactly cheap. uses .125 5052 aluminum. Other popular brands are Ranger, Triton and Crestliner. The larger models in the 19-23' range all use .125 guage.

Well thought I would provide that info on what the Professional Builders use on there boats up to 23'. The boat only hull weights were all around 2000-2200lbs,

I was curious and had to satisfy my itch. The largest boat was a Crestliner 23' Authority 2250, https://www.crestliner.com/authority/2250-authority/

Had my fun, OneWayTraffic those specs by Gerr look pretty right on.

Tom

[OneWayTraffic]

I think those are riveted Aluminium. 1/8th" hull. Clearly they think it's enough. AFAIK no NZ builders are building riveted boats these days, the market is all welded right down to craft of 4m (14') or less.

https://frewzaboats.co.nz/frewza-f14-fisher/

I'd note that the bottom on that is the same as on the 22.5' Crestliner. They use 2.5mm plate on the pontoons I think, which is about as thin as can be welded. They all manage though; I can name about 8 builders of that style of boat off the top of my head.

[cracked_ribs]

I think Tracker welds their boats now, but yeah, they're light duty lake boats.

You compare that 19T to something like a Silver Streak 18.6 center console...different planet. 3/16 5086 throughout. Built for offshore conditions on the west coast here. Of course, they're also twice the price...just a different ballgame entirely. But I would imagine anyone looking at a DE25 for Alaska, isn't planning on replicating lake boats.