Hull Material Tradeoffs: Wood/FiberglassPlastic/Aluminum/Steel

[cerich]

The knowledge, experience and expertise to even do that on liveaboard charter sized scale doesn't even really exist anymore in the USA and Canada. The train-up/staff-up/tool-up costs for a shipyard to even bid on such a project would be huge and probably kill it before even getting past the marine architect.

You can find the expertise in Chester Nova Scotia, and a couple spots in New England. doesn't much matter because you can't get the wood. Old growth is all gone and old growth wood lasts in seawater, new growth ...not so much.

Back in the day of old growth the old wooden squareriggers could easily see a hundred years plus HARD service, even RN ships in the 17-1800's often saw 50 plus years service.

The majority of the last of the old growth was used up by the turn of the 20th century and between WW2 and WW1 post WW2 you aren't seeing any new construction wood ships from old growth unless a VERY wealthy person or government footing the bill.

 

[wetb4igetinthewater]

You can find the expertise in Chester Nova Scotia, and a couple spots in New England. doesn't much matter because you can't get the wood. Old growth is all gone and old growth wood lasts in seawater, new growth ...not so much.

Back in the day of old growth the old wooden squareriggers could easily see a hundred years plus HARD service, even RN ships in the 17-1800's often saw 50 plus years service.

The majority of the last of the old growth was used up by the turn of the 20th century and between WW2 and WW1 post WW2 you aren't seeing any new construction wood ships from old growth unless a VERY wealthy person or government footing the bill.

Dumb question. What are modern day minesweepers made out of ? I know that the Greek Navy still is busy around Crete.

 

[Wookie]

Dumb question. What are modern day minesweepers made out of ? I know that the Greek Navy still is busy around Crete.

Mine hunters and mine sweepers are now glass.

Actually, look up helo squadrons HM-14 and HM-15. Mine hunters are often helo squadrons.

 

[rjack321]

You can find the expertise in Chester Nova Scotia, and a couple spots in New England. doesn't much matter because you can't get the wood. Old growth is all gone and old growth wood lasts in seawater, new growth ...not so much.

Back in the day of old growth the old wooden squareriggers could easily see a hundred years plus HARD service, even RN ships in the 17-1800's often saw 50 plus years service.

The majority of the last of the old growth was used up by the turn of the 20th century and between WW2 and WW1 post WW2 you aren't seeing any new construction wood ships from old growth unless a VERY wealthy person or government footing the bill.

The wooden boat school in Port Townsend WA also has the expertise. But they are not a commercial shipyard.

The limited old growth on Vancouver island that is still logged is mostly cedar which isnt' suitable for knees, or planking or any of these other structural members of a boat like Conception. My point was really building any kind of charter vessel from scratch, out of wood, isnt something that could be practically done. But you are right its not just the human capital which is functionally missing but the materials.

 

[Bob DBF]

Oh yeah, forgot about ferro cement, probably because it came and went so fast and every ferro boat I’ve heard about was condemned and scraped long before I got into the game. It was something they experimented with in the 60’s and 70’s as an alternative to moulded fiberglass for complex compounded shapes on sailboats.
Didn’t work out so well.

The big downside, it was as labor intensive as fiberglass, and a lot of time hulls were made thicker (heavier) for strength instead of better technique. An outfit in Sacramento built them commercially back in the 70's. They were mostly made by amateurs because of cost, if you don't count labor, I don't know how that's going now because you do need good steel for reinforcement.

If done properly, somewhere around 30', the vessel weight is around the same as a steel or fiberglass boat.

As for longevity, there is ferrocement boats still in existence from 1848, and a costal freighter still use from 1917.

The World of Ferroboats


Oh yeah, the guy that started the technique also included in the patent it's use for bridges and other structures, as well. I think the other uses overshadowed the boats.



Bob

 

[rjack321]

Most folks who don’t understand aluminum hate aluminum. I wouldn’t have anything else. Caveat is that it needs to be over 40 years old or with aluminum from Australia, where all of the great modern aluminum catamarans are built and designed. I assume rjack that your boat is a northwest build, maybe a zodiac and maybe 20 years old? Alcoa made a bad run of alloy that acts exactly as you describe. The Seattle ferry bought 2 of them, and Alcoa bought them back. Turns out they removed the manganese in the alloy and that allowed interstitial point defects in the aluminum, and they turned into Swiss cheese. My 40 year old crewboat and my newer 40 year old patrol boat do not have that problem.

For easy reference, plate is 5083 or 5086 and scantlings are 6061 or 6063. I heard of someone buying 5684 the other day, but I don’t know why you would. Weld wire is 5356 and never 4043.

No its about 10yrs old now (2007 build date and I bought it new)
Its made from a 5000 series alloy but I dont know the supplier or exactly which series anymore. Its from a Canadian manufacturer near Vancouver BC and I imported it myself for personal use.

 

[shoredivr]

No its about 10yrs old now (2007 build date and I bought it new)
Its made from a 5000 series alloy but I dont know the supplier or exactly which series anymore. Its from a Canadian manufacturer near Vancouver BC and I imported it myself for personal use.

No its about 10yrs old now (2007 build date and I bought it new)
Its made from a 5000 series alloy but I dont know the supplier or exactly which series anymore. Its from a Canadian manufacturer near Vancouver BC and I imported it myself for personal use.

Wolf Boats? @rjack321

 

[rjack321]

Wolf Boats? @rjack321

Polaris, not the snow machine polaris
Custom Aluminum & Inflatable Boats For Sale in Canada | Polaris Inflatable Boats

 

[Diving Dubai]

Is there a rough cut estimate of the cost difference between a wood/fiberglass and aluminum or stainless steel hull boats?

There are so many variables, it's almost impossible to make an apples for apples comparison.

Wood )if you could get and afford the materials, requires and incredible level of craftsmanship as well as design to build one. These skills are now getting rare. Unless it was a new build special replica I can't envisage a time where it's be used again

Fibreglass, lends itself to making more complex forms and repeatability for a production run. There is significant investment required for molds etc, but this can be offset with volume. It has a different skill set from metal (I won't say easier, since once I spent a month assisting in laying up wind turbine blades so I could fully understand the process) But it is more repeatable.

Aluminium is not a difficult material to work, unless you're starting to want complex curves. It just requires a different skill set and different understanding of material science. Issues highlighted up thread with corrosion, were long since solved in the aerospace sector (and now in automotive). Structural adhesives are common in use, and are stronger than rivets and in some instances welding. Over the longer term in some environments it's more durable.

If I were to buy my own 30/40' boat I'd want Ali - but maybe that's because I understand the material better so I'm biased!

 

[Diving Dubai]

Realizing coats, drapes, pillows, laminate cabinets, etc still burn.

This is the big one.

Remember there are regulations regarding soft furnishings in many industries. Aerospace, Automotive, Hotels, Care homes and domestic use, all have standards requiring certain flame resistance (Not the term resistance not proofing)

As you correctly say, everything will burn given teh correct temp. The idea is to limit these materials from becoming additional fuel too quickly. Even wood (lumber) can be pressure treated

There are products mainly used by live events, where you can spray the soft materials directly. The principle being, is that if you remove the heat source they will smolder or self extinguish - and have a fire resistance of a certain time (just like a fire door). It's generally not teh materials that combust, but the gasses they give off initially.

Older members will remember the changes to domestic furnishings in the 60/70's? To prevent them catching fire when people dropped cigarettes or fell asleep smoking in bed.

In principle then if say a battery or charge caught fire, on a countertop near a window with curtains, then if teh correct materials were uses, while they'd char they wouldn't coombust adding additional fuel to the fire

The flame retardant for soft furnishings does deteriorate with age (approx 5 years) and certainly with washing/moisture. In the Theatre industry the municipality test shows regularly on a fire inspection (blow torch) but you can spray treat. In automotive and aerospace, the fabrics are presumably different.

@Wookie will know what the regs are for fire resistance of materials on boats, not doubt it will depend on size and what is inspected or not