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Old 20-02-2010, 15:19   #61
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Notsure, the problem you are having is that stainless is used at all with aluminum. Not a good idea. Better than copper for sure, but metals that far apart on the galvanic scale shouldn't be used together unless isolated. Even then, in close proximity there can be electrolysis if underwater and oxygen deprived. There is nothing less noble than aluminum except zinc yet aluminum, when used properly and of the marine alloys (5000 series) is a very corrossion resistant material and it's strength/weight properties are pretty much unsurpassed for boat building. As with any material, there are do's and don'ts...

Zeyang, I have seen your website before and what a project! Nicely done. You must be preparing for taking on those tankers out there. I think you'll be just fine!
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Old 20-02-2010, 22:46   #62
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Notsure, the problem you are having is that stainless is used at all with aluminum. Not a good idea. Better than copper for sure, but metals that far apart on the galvanic scale shouldn't be used together unless isolated. Even then, in close proximity there can be electrolysis if underwater and oxygen deprived. There is nothing less noble than aluminum except zinc yet aluminum, when used properly and of the marine alloys (5000 series) is a very corrossion resistant material and it's strength/weight properties are pretty much unsurpassed for boat building. As with any material, there are do's and don'ts...

Zeyang, I have seen your website before and what a project! Nicely done. You must be preparing for taking on those tankers out there. I think you'll be just fine!
thanks.
yes i will use nylon isolation where i have to use stainless (like bolt for fastening the propshaft) Else i cant really think of anything else underwater which need to be fastened with bolts. throughulls can be done with alloy seacocks.

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Old 21-02-2010, 04:48   #63
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With the multiple overlaps and thick material, once welded up, you may find it pretty well framed and stiff enough to turn with a few temporary "thwarts" welded accross at deck level with a few braces. Draging it out on rollers and employing an excavator or even a tripod or two might work well if there isn't structure enough in the building. Keep us posted. This is a rather ambitious job with all that welding! I know the price of aluminum is down. Did you find a deal on wire and argon?
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Old 21-02-2010, 08:09   #64
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Hi zeyang,
Thought you might be interested but you are probably aware..
Marelon Flanged Seacock, 3/4" Pipe Size from FORESPAR

I like flanged because if they fail there is at least the recourse of removing and potentially pluging or capping...In that same thought, if I were building, I would keep all dicharges above the static waterline. Some may say unsightly, but to be able to bring one above water by changing tack could be handy for repair in the event of what could otherwise be a disaster. You might also think about a sea chest for any suply. Yes, there are just as many seacocks (coming from the sea chest instead of through the hull) but being able to access the chest from the boat and stopper the inlet 'upstream' of the seacocks might be advantageous in the event of a misshap! The biggest concern with aluminum when galvanic corrossion is checked by isolation or the use of non galvanic materials is crevass corrossion so planning for any possible events might be prudent seeing as you are building.
Prop shaft? Phenolic bearing blocks can help and if recessed, aluminum fasteners but there will always be the potential for water to do it's thing traped between the surfaces. A healthy corrossion factor built in with thickness, good paint, an eagle eye and zinc!..... Or skip the engine!
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Old 26-02-2010, 01:35   #65
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With the multiple overlaps and thick material, once welded up, you may find it pretty well framed and stiff enough to turn with a few temporary "thwarts" welded accross at deck level with a few braces. Draging it out on rollers and employing an excavator or even a tripod or two might work well if there isn't structure enough in the building. Keep us posted. This is a rather ambitious job with all that welding! I know the price of aluminum is down. Did you find a deal on wire and argon?
no good deal on argon. I spend approx 2000 RMB/week on argon now. (50 litre bootle) But got a good deal on wire though. Problem with argon is: its almost monopoly situation so i really cant bargain with them. Seems i use around 7 kg wire and 50 litre a week. thankfully im halfway into the welding, so cost will get down soon.

some flipping pics.
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Old 26-02-2010, 01:46   #66
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Hi conrad.

I agree about the through-hull. i have a few sleepless night trying to find a good solution about this. One solution is to make a tick tube in the middle of boat going to top of the water level and connect all this to that tube, but then if this breaks i have a big hole in middle of boat, so basically the best solution is something over waterlevel..

when it comes to water intake is a pipe in top of the keel going down to the waterlevel and then out. then i can pump in water through that. if it breaks it only fill the small part of that keel up to waterlevel.
bit hard to see on this picture but i will weld a plate over this keel structure so its a enclosed area not connected to the rest of the boat.

anyway. just some ideas yet. its a bit far away. so easy to worry about problems in advance. so i better take a step at a time else i get crazy. :-)
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Old 26-02-2010, 01:48   #67
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Do you have any idea of the weight of the open hull so far?
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Old 26-02-2010, 02:55   #68
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Do you have any idea of the weight of the open hull so far?
used 10 plates each of 265 kg. then its maybe 50 kg of welding wire and maybe 500 kg of temporary wood templates inside (which is not part of the hull)
i use 3x9 tonns chain hoist so i feel im on the safe side :-)
problem is the roof. its not very strong but sofar its still there.
I will be very happy when this stage is finished. its kind of nerve racking scenario, waiting for the roof to collapse anytime.

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Old 26-02-2010, 03:13   #69
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a guy told me about a funny boatbuilding cartoon strip.

anyone have this cartoon strip of a wife having christmasdinner with the kids while the husband is out in the boatshed building on his boat?

I would love to print out that cartoon strip and put it on the wall in the boatshed.:-)


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Old 26-02-2010, 07:46   #70
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Awesome deal all around! Thanks for keeping the pics coming!

The thru hull scene is always one of those things that can take too much thought and worry! The thing about making one oversize well reinforced "chest" with access to the inside (above waterline level) from inside the boat is that if one of the feeds from this 'chest' developes a problem it can easily be stoppered by reaching in and placing a plug which is essentially outside the boat and the water pressure is helping instead of fighting. If biult heavily and with thought there should be no reason for the chest to develope problems....the idea would be to keep all potential corrossion away. In otherwords keep the seacocks on the inside of the boat or no seacock to the chest itself. (I envision the chest to be six inch tube or pipe heavily gussettes to the hull and extending above waterline but short enough to be able to reach in to the bottom for cleaning etc. Some half inch holes through the hull plate as a rough strainer and no strainer inside it to help keep corrosion away. Put the induvidual strainers on the outlets, inside of the seacocks...perhaps an old portlight for the access/ top to the chest. But then again, if you could just do without the engine, what would need an intake through hull at all? Just fill the scuttlebut on deck for gravity feed running water! Also would take care of that other hole below the waterline for the prop shaft.....
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Old 26-02-2010, 08:54   #71
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Awesome deal all around! Thanks for keeping the pics coming!

The thru hull scene is always one of those things that can take too much thought and worry! The thing about making one oversize well reinforced "chest" with access to the inside (above waterline level) from inside the boat is that if one of the feeds from this 'chest' developes a problem it can easily be stoppered by reaching in and placing a plug which is essentially outside the boat and the water pressure is helping instead of fighting. If biult heavily and with thought there should be no reason for the chest to develope problems....the idea would be to keep all potential corrossion away. In otherwords keep the seacocks on the inside of the boat or no seacock to the chest itself. (I envision the chest to be six inch tube or pipe heavily gussettes to the hull and extending above waterline but short enough to be able to reach in to the bottom for cleaning etc. Some half inch holes through the hull plate as a rough strainer and no strainer inside it to help keep corrosion away. Put the induvidual strainers on the outlets, inside of the seacocks...perhaps an old portlight for the access/ top to the chest. But then again, if you could just do without the engine, what would need an intake through hull at all? Just fill the scuttlebut on deck for gravity feed running water! Also would take care of that other hole below the waterline for the prop shaft.....
when it comes to engine cooling, my plan is to use the latter part of the keel, fill it with glycone and run this as freshwater cooler. the exhaust could easily be above water.. (like the fishing boat have it)

i got that cool idea. what about a strong portlight on top of that big pipe and i can watch fish passing by :-) or even use it for fishing. that pipe will give me the feeling of ice-fishing through that hole.

I think only reason to have water intake is for the head (the outlet for head could be above water or into a storage tank) and maybe one for saltwater for the sink, else i really cant think of anything more.
or just have manual pump to fill a day tank for saltwater and use this.

ehh. anyway..

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Old 26-02-2010, 09:11   #72
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Well then just skip the intake all together!
Do you really want to deal with the septic slosh and small capacity, plugging and pumping? Check out the composting head thread on the forum.... ( a few laughs also.)

The time honored scuttlebut has much to say for itself as far as running water at the sink and shower are concerned. You can even make two. One solar heated. Weather gets rough and you are concerned about weight being high? Just let it out. It only takes a bucket to fill it again!....Hell, you could even rig a pump with a suction tube thrown over the side if you feel like using technology...But somehow I have the feeling you are the sensible type.

For the keel cooler you might want to create a long path for the cooling with baffles, but I'm sure you've thought of this.

It's just great to see someone doing it! Kepp it up. It looks great!!
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Old 26-02-2010, 09:19   #73
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One boat I looked at recently had it's saltwater tank mounted just above the shower. Top painted black and with a tight fitting cap. Below was a schrader valve fitted with a bicycle tire pump, Need a little pressure to your shower? Pump a little!
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Old 27-02-2010, 01:48   #74
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One boat I looked at recently had it's saltwater tank mounted just above the shower. Top painted black and with a tight fitting cap. Below was a schrader valve fitted with a bicycle tire pump, Need a little pressure to your shower? Pump a little!
There'sa a lot to be said for that...and who says it needs to be filled with sea water?
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Old 27-02-2010, 23:57   #75
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There'sa a lot to be said for that...and who says it needs to be filled with sea water?
Agree. its a good idea. Low-tech solar water heater in a welded box painted black on deck for shower or sink or even toilet flush. (maybe 20-50 liter is more than enough?)
Can swap between saltwater and freshwater also. fill with a bucket, electric pump or manual pump. even have it possible to open , to use it as storage when its not filled with water.. ifs its not used for drinking, i can just make them in alloy.
i will think more about this waterstorage box.
then the only seacock i need is outlet for head if i cant find any other good solution for this...

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