Bluewater Boat

[wolfenzee]

Originally Posted by bob perry

Wolf:
That's a sweet looking design and a great looking dog.
I always love those old Atkin designs.

Considering how much people are trying to talk down "obsolete" designs and building materials that means alot.
BTW the boat is composite manufacture, strip plank Honduras mahogany, top nailed with 3" nails, screwed onto 2"x3" double sawn fir frames at 12" centers and finished with 2 layers of fiberglass, none of the problems of either and all of the advantages of both (though when replacing the barrier coat I noticed the fiberglass was brittle with age, something I fixed with epoxy barrier coat). She may be a heavy old ocean cruising design, but she is quick in light air and solid in nasty seas.
There was a thread discussing newer beamy boats vs older narrow boats...my response was space vs grace.

[Mark Johnson]

I am a multihuller myself... however I have good friends, Wolfgang & Barbara, in a 36' aluminum, hardchine monohull, named MOMO. The hull and deck were production, (presumably in their home in Germany). They finished her out themselves, which is of coarse, the majority of the work. They have since cruised across the pond, cruised the Chesapeake, (where we met), and all over the Caribbean, for years.

Momo has shoal draft due to bilge keels, so is probably not so good to weather, but shoal draft is REALLY nice. I wouldn't live without it! Also, this allows them to go aground and sit upright, either by accident, or for beach maintenance.

Being metal, it is forgiving of the "bump in the night" that monohullers must think about on occasion. It is very tough!

Being VERY heavily insulated, and having IG glass for ports, nothing more than cooking dinner keeps her warm on a cold night. One sits at the raised dinette table and looks straight out of the ports. Under your feet is a HUGE storage area with pull out drawers.

And, the unpainted aluminum hull, which IS an aesthetic that takes getting used to, couldn't care less if the guy in his dugout canoe comes scraping and banging along side to sell you some fish. It is PRACTICAL!

The boat is seaworthy, shallow draft, and TOUGH, REALLY TOUGH! The deck is welded to the hull, the cleats and stanchion bases, as well as the bow rollers are too. No holes to keep from leaking.

It is in some ways opposite of my choice in boats, but after dinner over there, anchored in our creek during winter, I came to really like MOMO!

I have also met several other couples in aluminum monohulls, often centerboarders, and some were production boats. (All unpainted) They are VERY popular in Europe, but one bought in the States might be a better deal, because they bring so much less in the States.

If I switched to monohulls, I would consider something like this...

Mark

[irathersail]

I have a 34 Hunter and am planing to get down to the Keys and over to the Bahamas soon.Anyone have any pros or cons on this?

[Doodles]

Originally Posted by Mark Johnson

I am a multihuller myself... however I have good friends, Wolfgang & Barbara, in a 36' aluminum, hardchine monohull, named MOMO. The hull and deck were production, (presumably in their home in Germany). They finished her out themselves, which is of coarse, the majority of the work. They have since cruised across the pond, cruised the Chesapeake, (where we met), and all over the Caribbean, for years.

Momo has shoal draft due to bilge keels, so is probably not so good to weather, but shoal draft is REALLY nice. I wouldn't live without it! Also, this allows them to go aground and sit upright, either by accident, or for beach maintenance.

Being metal, it is forgiving of the "bump in the night" that monohullers must think about on occasion. It is very tough!

Being VERY heavily insulated, and having IG glass for ports, nothing more than cooking dinner keeps her warm on a cold night. One sits at the raised dinette table and looks straight out of the ports. Under your feet is a HUGE storage area with pull out drawers.

And, the unpainted aluminum hull, which IS an aesthetic that takes getting used to, couldn't care less if the guy in his dugout canoe comes scraping and banging along side to sell you some fish. It is PRACTICAL!

The boat is seaworthy, shallow draft, and TOUGH, REALLY TOUGH! The deck is welded to the hull, the cleats and stanchion bases, as well as the bow rollers are too. No holes to keep from leaking.

It is in some ways opposite of my choice in boats, but after dinner over there, anchored in our creek during winter, I came to really like MOMO!

I have also met several other couples in aluminum monohulls, often centerboarders, and some were production boats. (All unpainted) They are VERY popular in Europe, but one bought in the States might be a better deal, because they bring so much less in the States.

If I switched to monohulls, I would consider something like this...

Mark

I'm with you Mark! These boats make so much sense to me. We had a German couple in the slip next to us for a while and they had an Ovni 345. God I love those boats. They show up occasionally in the US but I haven't seen in deals $$-wise. Still expensive. Garcia is another production alum that I love.

[goboatingnow]

Aluminium boats are all very well and good but a professional looking repair requires significant skills and the right equipment not found in many yards. Anybody can repair GRP

Dave

[Jim Cate]

Originally Posted by goboatingnow

Aluminium boats are all very well and good but a professional looking repair requires significant skills and the right equipment not found in many yards. Anybody can repair GRP

Dave

Yeah, Dave, but the frp repairs done by "anybody" may not look all that professional... just like the alloy repairs done by "anybody"!

The equipment required to weld Aluminum is becoming far more common... the skills to do good looking work are indeed rarer.

However, the inherent strength of aluminum means that critical repairs are not commonly needed... this from a timber/epoxy boat owner!

Cheers,

Jim

[goboatingnow]

My experience of failure in aluminium
Is that the weld fails. It's often an area that's very difficult to fix well. Grp repairs can be done by competent amateurs and look ok. Very difficult to do the same in aluminium.

Also welding repairs often requires the adjacent furniture and insulation to be removed all leading to a far more complex and costly process. It's easy to bodge up a repair in aluminium but expensive to do it right. A good bit more expensive then GRP. In practice a well built GRP is as likely to survive or not survive the same types of damage as aluminium.

Dave

[Doodles]

Originally Posted by goboatingnow

Aluminium boats are all very well and good but a professional looking repair requires significant skills and the right equipment not found in many yards. Anybody can repair GRP

Dave

As we all know, everything with boats is a trade off. This is one I'd be willing to make, and an easy one since I wouldn't be too concerned about how the repair looked. Of course I also like the unpainted aluminum hull look which a lot of people don't.

[goboatingnow]

Steel
Ultimate tensile strength: 58,000 psi (400 MPa)
Yield strength: 36,000 psi (248 MPa)
Modulus of elasticity (stiffness): 29,000,000 psi (200 GPa)

5083-H321 Aluminum (as for plating)
Ultimate tensile strength: 44,000 psi (303 MPa)
Yield strength: 31,000 psi (214 MPa)
Modulus of elasticity: 10,400,000 psi (71.7 GPa)

Composites: (varies all over the map)
Ultimate tensile strength (knitted bidirectional laminates): 30,000 to 60,000 psi (206 to 414 MPa)
Yield strength: there is none, laminates are brittle
Modulus of elasticity: 1,900,000 to 3,000,000 psi (13 to 207 GPa)

GRP is stronger then rumour has it and aluminium , certainly that version in leisure Vessels is not as strong as the rumour. A lot of hype surrounds aluminium often based on experiences from commercial workboats. A very difference situation. ( the same is true of finely finished steel vessels.

I'm not running down aluminium or steel, but the hype runs away with itself sometimes. Ask ONVI to give you the STIX and AVS values for example.

Dave

[Jim Cate]

Originally Posted by goboatingnow

In practice a well built GRP is as likely to survive or not survive the same types of damage as aluminium.

Dave

Dave, this is an interesting claim! Can you document it?

And as to the quoted strengths of aluminum vs steel vs FRP... not sure that these numbers really address the issue of damage in yachts. For instance, abrasion resistance (as in grinding on a reef) is, I believe, far better for either metal type than for FRP. The ductility of alloy is an advantage in striking a floating object and so on. It's pretty hard to make a general statement about survivability because the specifics of an incident can generate really different damage scenarios.

The bottom line, I believe, is that well constructed yachts in any medium are more likely to survive strife than those less blessed by their builders.

And while ultimate survivability is an interesting parameter in boat selection, I think we tend to over rate its importance compared to more mundane factors like sailing performance, comfort, storage, etc. Only a tiny fraction of yachts are ever put in a survival situation, and few of those are ever lost due to the specific material from which they were built. The odd FRP yacht is lost due to faulty hull-deck joining etc, the occasional alloy yacht founders when a bad weld lets go, and steel yachts have been known to sink when corroded plating fails at sea. You can dredge up a documented failure mode for almost anything, but this sort of argument doesn't help the new boat buyer very much!

Having said all that, for the newbie cruiser, I too believe that a decent quality FRP boat is the best way to go. Lots of reasons, but perhaps the most telling one for me is that FRP is more forgiving of newbie-type mistakes, and will be probably easier to sell onward when the newbie realizes that he bought the wrong boat for him!!

Cheers,

Jim

[wolfenzee]

Originally Posted by goboatingnow

Steel
Ultimate tensile strength: 58,000 psi (400 MPa)
Yield strength: 36,000 psi (248 MPa)
Modulus of elasticity (stiffness): 29,000,000 psi (200 GPa)

5083-H321 Aluminum (as for plating)
Ultimate tensile strength: 44,000 psi (303 MPa)
Yield strength: 31,000 psi (214 MPa)
Modulus of elasticity: 10,400,000 psi (71.7 GPa)

Composites: (varies all over the map)
Ultimate tensile strength (knitted bidirectional laminates): 30,000 to 60,000 psi (206 to 414 MPa)
Yield strength: there is none, laminates are brittle
Modulus of elasticity: 1,900,000 to 3,000,000 psi (13 to 207 GPa)

GRP is stronger then rumour has it and aluminium , certainly that version in leisure Vessels is not as strong as the rumour. A lot of hype surrounds aluminium often based on experiences from commercial workboats. A very difference situation. ( the same is true of finely finished steel vessels.

I'm not running down aluminium or steel, but the hype runs away with itself sometimes. Ask ONVI to give you the STIX and AVS values for example.

Dave

not sure where it is (i'll try and find it) but a structural engineer did a comparison of all materiel uses to build boats , wood, fiberglass, carbon fiber, steel, aluminum, ferro cement etc.....and ran a huge battery of tests comparing them and when everything was said and done the superior building materiel for boats...was wood.
That said it would not be hard to throw in variables that would just as easily reinforce or disprove this.

[wolfenzee]

Structural engineering....this is waaaay of thread though it did bring up extra stresses but on a sea boat and the effects

[rgscpat]

How much do the costs of building a boat scale with

production number (build volume), and
quality and type of materials and components?

For example, how much more does it cost to incorporate vinyl, epoxy, graphite, and Aramid/Kevlar into a hull or the more vulnerable areas of a hull; ditto for upgrading the standing rigging, chainplates and attachments, etc.?

[Sabbatical II]

I am always intruiged that people think it is expensive to custom or semi-custom build. I suggest that it's not if you take into account that you don't have to pay to upgrade inadequate systems, less frequent repairs and a much better resale price of a well built medium to heavy displacement semi-custom yacht. I'm in the latter stages of building a 42' semi-custom yacht by Bluewater Cruising Yachts in Newcastle, Australia. The initial purchase price is about 50% more than if I bought a production yacht of the same size. I have seen 3 of these Bluewater brand yachts sold second hand at 10 -12 years old in the last 3 years. Even in a buyers market, all have fetched more than what their owners paid for them new simply because there are so few purpose built long distance cruisers on the market. I delivered one a few weeks ago and we were comfortably reaching at 8 knots in 15 knots of breeze with a much better motion than a lighter boat, so where's the trade off? So if you look at whole of life costs I expect the better engineering of the boat specifically designed for the task I will put it to will actually save me money. The compromise is that the builder only builds 2 a year and mine will have taken 2 years to complete. But who cares, we're cruising.

Greg

[goboatingnow]

I am always intruiged that people think it is expensive to custom or semi-custom build. I suggest that it's not if you take into account that you don't have to pay to upgrade inadequate systems, less frequent repairs and a much better resale price of a well built medium to heavy displacement semi-custom yacht. I'm in the latter stages of building a 42' semi-custom yacht by Bluewater Cruising Yachts in Newcastle, Australia. The initial purchase price is about 50% more than if I bought a production yacht of the same size.

Hmmm, Yes I see it now, a new Beneteau 50 for say 300K$ and then I pay another 150K$ to "bring it up to standard", yes yes

Dave