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Old 22-09-2010, 12:38   #151
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Originally Posted by beau View Post
owners don't always run their motors under load (charging batteries etc) and this leads to glazing of the bore.
I'm not certain how this became common knowledge in the cruising community or if it's mainly limited to this forum. I know it's a pervasive claim at this point. I've even seen forum-experts claim that the glaze can be removed by engine load. I think it's a safe bet that you aren't going to be able to put a crosshatch back on the cylinder wall with any amount of engine load. I suppose the implication is that the "glaze" is a deposit; I've taken a lot of engines apart and one thing I've never seen or even heard of is growing cylinder walls. It would be a neat trick though.

If there is a statistically significant association between extended low-load or idle operation and increased cylinder wall wear compared to loaded operation, I think it's more likely a function of a lubrication or cooling. Any diesel worth it's salt has a lubrication system designed to work at idle so that leaves lubricant and cooling.

Considering how many small marine diesels end up sounding the temperature alarm due to closed or clogged cooling inlets, I would argue that, per Occam's razor, overheated engines would be the most likely source of the noted instances of "glaze" and low-load operation is an innocent bystander. Diesels of all shapes and sizes run at idle for hours on end all over the world while overheat operation is a proven way to damage cylinder walls.
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Old 22-09-2010, 14:39   #152
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Re:Earthrace

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Originally Posted by Event_Horizon View Post
Excellent mentality. Just make sure if you have a HIGHLY skilled professional boat designer give your idea's a once over if you try to build a submersible. Building a general approximation, tapping on the side and calling it sturdy...could lead to disaster.

I'd also say the "extensive engineering" would have to be around hull design. The whole...dealing with water ingress...is the easy part. If you look up the system on earthrace it's pretty simple.

I have to ask...if you are planning on avoiding bad weather. Why consider a wave-piercer at all?
Event,
I would definetely have an experienced marine engineer as well as boat yard review the plans and perform the build. I don't consider something this important a back yard project. I would plan to try to avoid bad weather, but living on the ocean you will not always be able to get to safe harbor all the time. This is why I want a design that can handle all but the "perfect storm" (and that if needed). I like the overall look of the Earthrace boat, although asthetics isn't the main factor in the boat design, function and economy are.
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Old 22-09-2010, 17:05   #153
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Event,
I would definetely have an experienced marine engineer as well as boat yard review the plans and perform the build. I don't consider something this important a back yard project. I would plan to try to avoid bad weather, but living on the ocean you will not always be able to get to safe harbor all the time. This is why I want a design that can handle all but the "perfect storm" (and that if needed). I like the overall look of the Earthrace boat, although asthetics isn't the main factor in the boat design, function and economy are.
Good good...I'm not trying to discourage you. On the contrary as an engineer I'm extremely interested in your idea's and how to make them work. I just get this uneasy little feeling sometimes when people come to me or express idea's that are inherently...dangerous.

Beau's boat is unique and interesting. I'm not sure whether his hull design is working as intended, however what I think he did very well was build a boat that was in line with the general philosophy of "what do I really want?". His boat can be shipped, its comfortable, livable, and stable as a multi with some sailing capability. He did something he can be proud of, mission accomplished.

I understand that was earthrace does is very very cool. However, what I don't understand is why you would want your boat to do something similar. Earthrace was designed specifically to go into bad weather and move efficiently at high speed through large choppy seas. It doesn't sound like this is your intention, and I'm not convinces it's "safer" either. My point is, if you went to the brilliant engineers of earthrace and said "build be a multihull live aboard that is efficient, and very robust in heavy seas" it is very unlikely that boat would in any way resemble earthrace.

**aside, If you do find a marine engineer that feels comfortable working with wave cutting hull design (I suspect these people are very rare) please send me a PM with his e-mail or something. I'd love to pick his brain.
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Old 22-09-2010, 18:47   #154
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Beau's boat is unique and interesting. I'm not sure whether his hull design is working as intended
You forget I built 5 1/2 scale prototypes that I used to perfect the principles involved. It is working exactly as I predicted but the builders(who build commercial catamarans) overbuilt it, and it weighs more than originally estimated, so i needed bigger motors.

Quote:
If you do find a marine engineer that feels comfortable working with wave cutting hull design
They are all in Australia and New Zealand (Earthrace was designed in New Zealand)
The US navy have contracted an Australian company (Austal)to build "state of the art" trimaran wave piercing vessels
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Old 22-09-2010, 21:15   #155
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Re: Designers

Beau,
Thanks for the info on the location of designers that deal with "outside the box" designs like Earthrace and your boat. I'll make a note of it for future reference.

Event,
I do think Earthrace looks very, very cool, but I don't expect my vision to resemble it much. Off the top of my head (since I'm just getting started on ideas) I see my design more closely resembling one of Beau's designs shown many pages back. The v-wing shaped design, which should provide more room as well as stability.
I still think the "containerized shipping" design of his boat is cool too and a great way to quickly and economically move the boat across the world, and would like to play around with that concept as well once I get into the CAD classes and can do some 3D modeling. I think he's got a sound design and has just skimmed the surface on what may be the next generation of design for a select group of travelers seeking this type of portability.

I was watching a yacht show on the Travel channel last weekend and they featured the RORO ships that transport boats across the Atlantic. They stated the charge was $1000USD/ft for the service. For smaller boats like most people on here have (35-60ft range or so), does anyone know if the charge is the same or if there are cheaper transport for the smaller boats? $1000/ft is WAY to much to spend to move a boat across the pond, and this would definitely lead me towards designing a container shippable boat if I plan on moving around the world allot.
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Old 22-09-2010, 21:22   #156
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Retractable stabilizer mechanism

Beau,
Did you consider a hydraulic setup to extend/retract the stabilizers on your boat when designing it? Just curious and if so why didn't you go that route.

Also, do you have plans on ever offering the blueprints for your design for sale in the future once you have it tweaked and finished for others that would like to build a similar design? Even if they don't build the boat as drawn, the design can be a starting platform to work from to customize a boat to their specs. Thanks.
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Old 22-09-2010, 23:03   #157
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When you say you saw Ro/Ro what do you mean.
There is a ship that lowers inself into the water and then pumps out the tanks after the yachts are aboard, which is very,very expensive.
A RO/RO as I know it is more like a car carrier. A friend of mine just bought a boat in from the USA to Australia in an RO/RO it was 10ft wide and 35ft long, It cost a bit more than a 40 ft container ($3,500) but not that much more. They use a trailer to bring it unto the boat.

I plan to offer a design and build service. Australia produces a lot of Aluminium and lot of boats are made from Aluminium in this country. Our tradesman have had a lot of experience. Currently most of the catamaran ferries for the world market, are built in Australia I have a marine engineering company (who built mine) who offers a good rate when he is between big jobs.
I could supply plans but as an ex boatbuilder myself, I would recommend at least the structural part be done by professionals who know what they are doing. (shipyards tend to specialize, not everyone knows how to properly build an aluminium multihull)

I would be happy to design up something to your requirements/have the design approved by a marine engineer/ get quotations from a number of different companies in this area/supervise construction to a basic ready to fit out stage aluminium structure completed. No electronics/no engines and no internals ,this is best done in your home country.

What happens here quite often is the shell is made here and shipped to the Phillipines where the internal fitout can be done for a fraction of the price here.

In regard to hydralics on the outriggers. Of course it is possible and expensive and just one more thing to go wrong.
My original idea was to use a system similiar to what is used on the Danish built Dragonfly Trimaran.
However I found it wasn't really suitable, too much slop.
Plus as an ex sailor I had the outriggers far apart.
I found the boat more suited as a motor/ sailor and there was no need to have the outriggers as far out for motoring plus any sailing was going to be in light/medium conditions and downwind. If the wind exceeds 25 knots I motor.
The current system I have is fixed and bolted system that can be taken off for shipping
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Old 22-09-2010, 23:26   #158
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This is my latest version, I also am working on a 50ft X 18ft version but it does not fit into a container

The main differance compared to my current version is the the bow height has been increased an this area is now used for a large standing headroom shower and toilet. The "floor" is raised on the main living area and aft deck, no step down, full headroom in the bedroom and a large (as you have at home) galley.
The aft deck call be fully enclosed or open and has insect screens.
Helm is up, with a removable roof which has solar panels.
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Old 23-09-2010, 00:27   #159
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What happens here quite often is the shell is made here and shipped to the Phillipines where the internal fitout can be done for a fraction of the price here.
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If I did that and then bought it back to Australia would I have to pay import on it or as it was made hear would it be tax free?
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Old 23-09-2010, 00:28   #160
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I checked with my friend who just brought in a 35 ft X 9ft Glacial bay catamaran from the USA to Australia and it cost him $30,000 so i was wrong it looks like the Hi cube 40 ft container is the best way to go after all.
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Old 23-09-2010, 00:32   #161
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If I did that and then bought it back to Australia would I have to pay import on it or as it was made hear would it be tax free?
I don't know about that, if you had the boat built here and registered here it is an Australian boat. If you ship the boat or sail it across and have the interior work done overseas, who is to know.
You are just returning into Australian waters with an Australian boat so NO import duties?
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Old 23-09-2010, 01:30   #162
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If there is a statistically significant association between extended low-load or idle operation and increased cylinder wall wear compared to loaded operation, I think it's more likely a function of a lubrication or cooling. Any diesel worth it's salt has a lubrication system designed to work at idle so that leaves lubricant and cooling.
... Diesels of all shapes and sizes run at idle for hours on end all over the world while overheat operation is a proven way to damage cylinder walls.
Most of those diesels cycle between low and high loads. Running for an extended time at low load causes carbon to deposit in the head - this is called "coking". I don't know that it would lead to "glazing" of the cylinder walls, but it could lead to premature wear and/or detonation.
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Old 23-09-2010, 02:07   #163
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I have seen an alarming failure rate in Diesel motors on boats that i have owned or friends have owned.
I am an ex farmer and our diesel tractors went forever plus i had diesel trucks and never had a problem.
Why do diesels on boats have different reliablability factors.
Is it all about running with no load or marinizing problems or what else.
Yes I know I will get replies of i have had the same diesel in my boat for thirty years etc but that is not the norm and I would like to know why.
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Old 23-09-2010, 03:00   #164
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Some factors to consider (compared to a tractor)

- The marine environment is a very wet, corrosive and harsh one
- Marine diesels are run infrequently for short periods compared to a tractor
- Marine diesels are run (probably) at 50-60% load most of the time
- Marine diesel cooling systems are sensitive and predominantly crappy - there must be something better than salt water to coolant heat exchange
- Marine exhaust systems are stupid - Who really thinks dumping salt water into the exhaust manifold is a good idea?
- Many marine diesels are really old and overhaul practices are probably sketchy - around here they are probably overhauled on the floor in a dirty boatyard by a guy who has only a slight clue what he is doing
- Newer marine diesels appear light weight in the crankcase and head IMO.

The reason for overhaul I read about are most related to:

Corrosion - Boat left on hard for 5 years, water backing into valve/cylinder corrosion (also left untended)
Compression - Head gasket failure, valve seat failure
Power upgrade - Good donks pulled for more power or cruise prep
Tired of Flocking with Troubleshooting - Everything from smoke (white, blue, black), hard starting, quits when warm, won't make power/low rpm (not related to compression)

I think lot's of overhauls happen that aren't necessary. I rarely, maybe never, have heard of a marine diesel throwing a rod or sucking a valve.

Expectations - My Volvo MD2010 was put in my boat new in 1981. It was overhauled (on a dirt floor) around 2000. 19 years ain't bad for a first run. Rubber and gaskets sometimes just wear out. At 7 years my engine needs some TLC which it is now getting. Based on the overhaul history I don't expect 20 years this time. I'll be happy with 10-12.

Most boaters expect to do little maintenance and expect the donk to run 20 years. I think the stories of failed donks is disproportionate to the stories about donks running fine at 10 and 15 years.
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Old 23-09-2010, 21:50   #165
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I think lot's of overhauls happen that aren't necessary. I rarely, maybe never, have heard of a marine diesel throwing a rod or sucking a valve.
This is almost assuredly the explanation for the vast majority of engine "failures". Unwitting owners have an engine that wont run - likely due to water in fuel or some other minor malady, or perhaps the engine develops a crankshaft or valve cover leak: The technician detects deep pockets and sells the overhaul. Either by way of a bald faced lie or the "while you're in there" argument which, in general, simply does not apply to a perkins or yanmar that picks up a few hundred hours a year.

Unless it is seized (water intrusion) or knocking (piston slap, rod or main bearing failure, valvetrain failure, or otherwise catastrophic damage) - The latter being nearly unheard of for the manufacturers noted above - it's a safe bet it doesn't need a rebuild.

Note: Knocking, not ticking which would likely be valvetrain wear/adjustment and again, not warrant a complete overhaul.

I would argue that even relatively serious top end issues such as valve guides or a blown headgasket should not automatically mean an engine-out rebuild of the reciprocating assembly.

It's always frustrated me to see or hear about people being taken by mechanics. I'm afraid it's not nearly as rare as one might hope.
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