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  #771  
Old 06-25-2013
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Re: Bob Perry's take on Wolfenzee's dream boat

Quote:
Originally Posted by SloopJonB View Post
Brent's comments are very reminiscent of Bruce Roberts stock plans business and John Sampson back in the days of ferro.

The fact is that nothing is cheaper than a shrewdly purchased used boat - especially now in this depressed market.

I know this for a fact as I've built, restored and bought turnkey used.

Building was by far the most expensive.

Having said that, if I was for some reason possessed enough to take a 30' through the North West Passage, I think one of Brent's boats would definitely be on the short list.
Back in the mid 90's I was seriously wanting to build a boat. I was corresponding with Dick Newick.I liked his 36' tri Echo .I also liked Pats which was his personal boat.She was 52', constant camber.He wrote me back saying the materials for Echo would be about $40K for the basic boat with a main and jib, Pats would be about $150K for materials.He said for the money it would cost for the basic materials for Echo he had a 38 foot native fully equipped and ready to go.He gave me a nice lesson in fiscal reality.
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Re: Bob Perry's take on Wolfenzee's dream boat

Brent and I have debated this around the web probably for at least a decade. This is from some of the earlier discussions on this topic.

Build time and cost: While it is true that you can tack weld a steel hull very quickly using an 'origami' technique, if you compare the overall build time with welding, finishing and constructing an interior to an equal level of finish, in prior analysis that have been posted previously on other sites where we have debated this in the past, other techniques require similar cost and time to build, which is especially true since steel prices have ratcheted up relative to other materials.

If time and money are the prime determinants, in the size boats that we are taking about, then stitch and glue sheet plywood sheathed in epoxy and glass inside and out would easily beat steel on cost (and on strength if of equal weight). The time is greatly shortened on either Orgami boats or on plywood boats with accurate cutting patterns for the interior bulkheads and hull panels.

The Steel vs. Fiberglass hammer argument:

This is a favorite of the steel guys which says steel is better than glass because a steel hammer would damage a glass boat.

Again, I will refer to my previous analysis on this one. Start with the hammers, to begin with we need to compare hammers of equal weight and weight distribution. In other words, for example, to maintain that weight distribution, we need to compare say a 20 oz framing hammer made of steel to an fiberglass hammer of equal weight and weight distribution. The fiberglass hammer would have a head nearly 2 feet long and 3 inches in diameter. If we use the laminates that I have advocated in the past, I would use the vinylester resin typically used in bullet resistant military and crash helmets and a kevlar laminate in the actual impact areas. The impact resistance of that hammer would be several times greater than the steel hammer.

Then we need to look at the steel and glass that we are beating up with these hammers. In a past analysis that I posted on the Origami website, I had calculated that a fiberglass panel able to stand up to a 20 oz framing hammer would be somewhere between 3/16" and a 1/4" thick if the panel size was limited to around 2 feet span. If we compare that panel to a steel panel of an equal weight steel, the steel would be just a tick thinner than 5/100's of an inch (.05"), in other words something slightly thinner than the thickness of steel sheet metal used for body panels on a modern automobile. I'll take the equal weight fiberglass hull and steel hammer any day over the 20 oz. fiberglass hammer beating on an automobile body panel.

Demolition Derby:
It comes down to the same thing here as well. Again we are talking about equal weight boats of steel, fiberglass and engineered laminate over cold molded plywood.

Lets start with the problem at hand namely the equal weight part of this sentence. If we compare the relative density of the materials involved, they are as follows: Steel= 7.85, Fiberglass= 1.92, and cold molded construction= .45 (3/4" port orford red cedar strip plank with two diagonal layers of 1/4" port orford red cedar veneers and a final longitudinal layer of douglas fir with an exterior laminate of vinylester resin and kevlar with minimal non-directional glass), So if we start out with a 1/2" thick fiberglass hull, the comparable weight steel hull would be something less than an 1/8" thick (roughly 3 MM), and a cold molded hull would be roughly 2 1/8" thick. And when the numbers are run, the fiberglass hull would have slightly more than 4 times the bending strength and roughly double the impact resistance. The cold molded hull would have nearly 11 times the bending strength, and somewhere between 3 and 4 times the impact resistance of steel.

Again, in a demolition derby, I will take the other materials over steel any day, especially when you consider how little steel would be left out of 1/8" plating after a decade of rust.

And as you noted the last time I posted these numbers on another website, if I remember correctly, your hulls are typically 1/4" and 5/16" plate. If we compare a 5/16th steel plate, to equal weight fiberglass and cold-molded hull panels, the fiberglass hull would be nearly 2 inches thick and the cold-molded hull would be 5 inches thick. The strength ratios remain the same.

I come back to my original contention, that of all of the materials that one can build a boat, on a pound for pound basis, steel is one of the weakest materials to build a boat, and if maintained in an equal fashion to the other materials, over the life of the boat, according to all studies that I have seen, a steel boat is one of the highest lifecycle maintenance forms of construction that one can chose.

But in the end, little of that matters, in sailing we make choices based on our goals, fears, and sailing venues. For some steel make sense. For most, there is little logic to owning a steel boat. The above was intended to illustrate the relative strength of materials by weight. I chose to use panel thickness as clearest way to illustrate basis of my comments on the relative strength of materials by weight. In the example, the greater thicknesses of fiberglass and cold-molded construction result in strengths that are substantially higher than comparable weight steel.

But as sometimes noted, no one would build a boat a boat this size with panels as thick as those in my example. But if you reduce the panel thickness and the strength of the panels equal to steel, you end up with a hull thickness that is closer to normal practice. In that case, you can still achieve equal strength to steel, but a very significant reduction in weight. And that is my primary point.

I don't disagree with Brentís argument that "The truth is that steel puts a great deal of strength and toughness into a compact packageĒ but I add that this strength comes at the cost of significant weight. In fact, more or less that is my key point. I raise this point in reference to someone considering custom building a boat with concerns towards the relative strength of the material being chosen.

The steel guys like to ask questions like; "Why don't they make icebreakers out of fibreglass or wood?" but to answer that question, until the early 1950's icebreakers were typically sheathed in Ironwood. Since then specialized steels have become the norm. As I have mentioned in prior discussions, steel really comes into its own as a vessel gets larger. When you talk about a vessel the size of an icebreaker, the compactness of steel becomes a significant advantage. Also Commercial vessels tend to be short lived compared to yachts. Beyond that, when you talk about an icebreaker, high weight is an advantage rather than a disadvantage.

Lastly, I am in agreement with statements in other discussions that, "Steel is certainly not for everyone, but neither is fiberglass, nor cold-molded wood." That is essentially the same point that I was making in my conclusion, "In any event, in sailing we make choices based on our goals, fears, and sailing venues. For some steel make sense. For most, there is little logic to owning a steel boat."

Respectfully,
Jeff
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Re: Bob Perry's take on Wolfenzee's dream boat

Thanks a lot, Brent.

Like I said in an earlier post I've seen people in a steel hull come to grief on rocks. but you constantly disregard the experiences of others, and only answer what is convenient using a rather unpleasant "tone" (calling it BS).
Btw. that experience still give me bloody nightmares.


/Joms

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On of my 36 footers,while leaving Suva, pounded across 300 yards of coral in a big sea, then was pulles back over it by a tug , with no visible hull dammage, to continue her circumnavigation. Many of my boats have hit the rocks at hull speed, with no dammage . That "NO hull will save your bacon in that situation" is a well disproven myth, propagated by those trying to sell hulls which wont ( or trying to justify buying hulls which wont).
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Re: Bob Perry's take on Wolfenzee's dream boat

Bob I know your hot on the AMG/Benz but could it do this?
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Re: Bob Perry's take on Wolfenzee's dream boat

Jak:
Another 100 yards and they would have made it to my beach shack! That's an amazing video.

What I really want is a So Cal Woody wagon with big, fat tires and a blower sticking out of the hood. Ok, maybe not the blower but a souped up classic woody would be my dream car. But I'd settle for the AMG Mercedes.

I did several boats with Dennis Choate and Dencho in Long Beach. At lunch time we would walk about three block through an industrial section of Longbeach to a little Mexican restaurant. Great food. On the way to the Mexican joint we would walk by a guy who restored cars. His place was usually filled projects in every state of completion and maybe one or two completed cars parked outside. For me this was car dreamland. You could just walk into the shop and poke around. Nobody said anything. My fantacy was to buy one of his restorations or hot rods and drive it back to Seattle.
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Re: Bob Perry's take on Wolfenzee's dream boat

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Originally Posted by JomsViking View Post
Thanks a lot, Brent.

Like I said in an earlier post I've seen people in a steel hull come to grief on rocks. but you constantly disregard the experiences of others, and only answer what is convenient using a rather unpleasant "tone" (calling it BS).
Btw. that experience still give me bloody nightmares.
I notice no-one's mentioned concrete. As a kid seeing a world-traveller's properly-built concrete hull come to grief on a reef in north queensland wasn't a pleasant experience either.

Actually that was one of the main reasons my parents had an Adams-designed steel-hulled 52-footer built not long after..
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Re: Bob Perry's take on Wolfenzee's dream boat

We hit a ledge going 6 knots under power in my Fathers Cal 33.It was a super low moon tide.It was in the channel.Nobody new this ledge was there until we hit it.It was in the channel into Cohassett harbor.This was the lowest recorded tide in decades.I was in the companion way.the boat stopped dead.I flew forward and landed on the table and banged my head on the galley sink.The boat was fine.No leaks.In 1976 there was a freak May northeaster in New England.100mph winds and a blizzard to boot.It created a massive storm surge.Most of the boats in the outer harbor at Cohassett broke there moring pannants and wound up on Bassings beach.While bouncing up and down in the surf
a crack devolped in the trailing edge of the keel right where it joined the bottom.Many patches were applied but it consistantly leaked.The boat flexed to much at that point.Finally they glassed in some floor timbers to deal with it and it worked.But the Call 33 had a very flat bottom so the floors rose well above the cabin sole.We had to cancel all the dances in the main cabin after that.
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Re: Bob Perry's take on Wolfenzee's dream boat

Quote:
Originally Posted by Hartley18 View Post
I notice no-one's mentioned concrete. As a kid seeing a world-traveller's properly-built concrete hull come to grief on a reef in north queensland wasn't a pleasant experience either.

Actually that was one of the main reasons my parents had an Adams-designed steel-hulled 52-footer built not long after..
Yes, well, that is hardly surprising is it ? Of course there are good concrete boats but I'm afraid the material has been abused so often that it is unlikely to ever make a recovery ... if indeed it deserves to. Not a material for boat building that appeals to me but when it's done right there is little inherently wrong with it. Whether or not it in anyway can complete with GRP or Cold Mouled timber is of course another story. Bit like steel really.

As you know Hartles old man, our old girl was steel and we loved her dearly but it must be accepted that she was a whole lot more work than her plastic or timber sisters and most certainly slower though not apallingly so.

Again repeating simple facts .... the steel VDS34 is significantly heavier than her plastic/timber cousins yet carries less ballast due to the weight of the steel hull itself. I doubt there is any benefit to be had there. If I had my druthers I'd druthe have timber .... glass coated.

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Re: Bob Perry's take on Wolfenzee's dream boat

Advantage metal ( Fe/Al) has is they are iso in all directions ( compression/extension etc) and they will generally fail gradually ( e.g. dent rather than fall catastrophically). In engineering terms one can make the joke they are more plastic then the plastic boats especially the cored ones... However in all other regards except for specialized applications for the average cruising sailor other options make better sense when you crunch the numbers. Thought the "little" Bougainvillea was a thing of beauty until we ran the numbers. One of the troubles is on this side of the pond the market is limited. Still, there are some truly glorious boats in metal The Kanters K+M s, Puffins, Boreals would make most reading this thread quite pleased. Modern coating systems have come quite a way and I like the look of bare aluminum if the hull is fair. Service life is likely to exceed your own with adequate maintenance. Feel any material can make a great boat with a good design and good execution. Think some of the above posts are a bit harsh.
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Re: Bob Perry's take on Wolfenzee's dream boat

Jak- can't recall the number of times I heard of or seen a motor boat rip off its strut and prop(s) blasting across Brown's Bank. Keep your dad out of Plymouth (GRIN).
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