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  #316  
Old 04-17-2012, 08:40 AM
BertKu BertKu is offline
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Quote:
Originally Posted by masalai View Post
Hi Bert,
I am not criticizing your inventive capacity, only trying to illustrate that the wind is not such a great source of energy unless you can fit BLOODY BIG blades or go for many, in a wind-farm like operation (not good for a boat)... It is good to capture energy that is available in nature, but there are conversions that limit what you can get out of the wind (or sun for that matter)...
Fully agree.

Quote:
It is not the changes in direction (relative to the boat), going N, S, E, or W, - - BUT the up and down and side to side ROCKING motion that interferes with the flow of air around the 'airfoils' that make up the wind energy harvesting systems that will become less effective - If the airflow is NOT clean flowing around the 'blades' of the device, it will not work effectively, PERIOD... The movement naturally inherent in the identified design styles, are for comparative - illustrative purposes - - is all that I was comparing...
You have a very valid point, at the same time, for that reason I thought that the Helix concept may be a solution.

Quote:
When salt gets at copper and it is heated by electrical flow it goes black and presents greater resistance and heats up even more, such that it may ignite - - - I have seen it happen on a boat where the anchor winch was 3 phase AC and was wired using standard domestic cable heavy enough for the rated load... Within 3 months it caught alight. No anchor, up or down...
I suspect without being obnoxious, that there was also another reason. It is in my view the salt which oxidizes and makes the copper black and dark. Although the blackening makes the mm2 smaller of the good copper. Somewhere there must have been an underlying problem with the circuitry. Most likely under rated mm2 for the large current flow during operations.
Bert
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  #317  
Old 04-17-2012, 08:50 AM
BertKu BertKu is offline
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Meranti wood

I have to go back to all my design and problems. However nobody has answered my question, whether I could use Meranti wood for the boat. I asked many Forum members, no response, anybody who could or is willing to give me an opinion?
Bert
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  #318  
Old 04-17-2012, 11:51 AM
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Tad Tad is offline
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Quote:
Originally Posted by BertKu View Post
I have to go back to all my design and problems. However nobody has answered my question, whether I could use Meranti wood for the boat. I asked many Forum members, no response, anybody who could or is willing to give me an opinion?
Bert
I would say don't use it. Like all boatbuilding questions the answer is not really black and white. Meranti is one name for woods from the family Shorea, which also includes Luan and Balau among others, what is currently sold as Philippine Mahogany is also from this family(total garbage). None of them have any rot resistance, not good for boats where mold and fugus starts at the drop of a hat. Yes, it can be used if totally and thoroughly coated with epoxy, and you are willing to take a risk. But is it worth it, only you can answer that.
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  #319  
Old 04-17-2012, 12:28 PM
tugboat tugboat is offline
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Bert--as you know--im on your side- -remember back on your posts somewhere here- we talked about electric motors/hydraulics etc. for my tug??- what the issue came down to was the ability to charge and hold energy fast enough...now perhaps this doesnt pertain to your system because im just not good (yet) at electrics so not sure what you require...
but the reason that idea got abandoned for me was it just wasnt practical. I would need a diesel to charge my bank ..and wind or solar was too slow for my needs...maybe its different for your application because i am not sure of your SOR(i give credit to PAR for that term).but if you do any long distance travel you are going to have issues...now if its short durations and just gunk-holing around your area --then just a simple charge at dockside will do the trick..but any further distances and its an issue unless you hoist a sail and charge while sailing...when i did my investigation someone said something to me that really hit home--and he was correct--this was 18 months ago--his quote " " at present-there isnt a practical solution yet to carbon fuels" when he said that it hit home just how hard it was to achieve what i wanted and had to let it go...

i realized--i needed a different route--and i vowed at that time i would never go with diesel or gas--hence im on the steam path...as obsolete as it may be...im glad i found out that info

now about Meranti--- Bert thats not a question i or anyone can answer for you--just like: "should i use steel over FAL"? etc--it has to be personal... but in mho- meranti is definitely a good structural ply.
here is "noahs marine" description:

Item Description

B/BB Meranti face & core veneers. 1.5 mm face veneers. Equal or nearly equal laminations. WBP Gluelines. Medium weight, good bending & finishing characteristics. Excellent structural plywood. Meets BS 1088 Standards Pending Lloyds certification.


If i was doing a ply boat id use it...but thats me...btw its expensive too!!
hope that helps?

Doug
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  #320  
Old 04-17-2012, 01:52 PM
BertKu BertKu is offline
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Quote:
Originally Posted by Tad View Post
I would say don't use it. Like all boatbuilding questions the answer is not really black and white. Meranti is one name for woods from the family Shorea, which also includes Luan and Balau among others, what is currently sold as Philippine Mahogany is also from this family(total garbage). None of them have any rot resistance, not good for boats where mold and fugus starts at the drop of a hat. Yes, it can be used if totally and thoroughly coated with epoxy, and you are willing to take a risk. But is it worth it, only you can answer that.
Thank your Tad,
The reason why I looked at Meranti wood, which is sold here in this area, as all houses and many structures at the sea side are having Meranti window frames and doors. I am 800 meters away from the sea and salt deposit is quite high. You can imagine that it must be worse 80 meters from the braking waters.

I can get Rhodesian Teak, but the S.W.G is around 1 versus 0.6 of Meranti.
I also looked at Ceder, but the supplier cannot get me any details. It is lighter, but without details, I am hesitant.

I will have to travel some 2 x 400 km again to shop around. I am happy with my expensive French Lloyds approved Marine ply. Just all the other timber is
on my search list. Thanks for the info.
Bert
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  #321  
Old 04-17-2012, 02:55 PM
tugboat tugboat is offline
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Quote:
Originally Posted by BertKu View Post
I am happy with my expensive French Lloyds approved Marine ply. Just all the other timber is
on my search list. Thanks for the info.
Bert
Bert to me thats a great idea- use what your heart tells you to go with!!

plus its approved. no worries there. too bad its so expensive..
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  #322  
Old 04-17-2012, 03:34 PM
masalai masalai is offline
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What I used on CNO is balsa cored and balsa turns to "porridge" after 12 months (see the voyages of Thor Hyadral - Kon Tiki across the Pacific, ending at Mooloolaba, just north of Brisbane and only just making it)... So I have sealed it in grp and additional coats of epoxy and finish with marine paints... Also a little paranoid about bumps that may break the seal...

If I build again it will be in "marine ply" and sealed with a pre-coating of West-System-GRP on both sides and an epoxy glue, with fillets and tape reinforcing the build joins (NO SCREWS left in )... With multiple layers on the bottom and a couple of thin layers to the chine above the water-line... I feel that "CNO" will outlast my years on this earth - my preference for ply now is just a personal choice and not based on quality or suitability of material - I am not so concerned about a "weight penalty" of ply-cored vs balsa-cored... as has been said above - essentially the choice is yours...

- As a boat-building timber I like 'Kiri' or 'Powlina' (same thing) which is now plantation grown - maybe not mature enough for ply yet? . . . a search using "paulownia timber" yeilded the following as a sample.........

http://en.wikipedia.org/wiki/Paulownia

http://www.highpointtimber.com.au/

https://www.google.com.au/search?q=p...w=1920&bih=943 = pictures of kiri & products
__________________
Try to be helpful...
Remember that there are at least two sides for every story...
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  #323  
Old 04-17-2012, 03:39 PM
BertKu BertKu is offline
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Quote:
Originally Posted by tugboat View Post
Bert to me thats a great idea- use what your heart tells you to go with!!

plus its approved. no worries there. too bad its so expensive..
Thanks Doug,

I am wondering whether the Meranti sold here, is of a different quality as sold in the States. I have no experience with Meranti plywood sheets, only with the hard, dark brown Meranti 6" x 1 or 2" and up to 18 feet long. I will ask Tad.
Bert
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  #324  
Old 04-17-2012, 03:46 PM
BertKu BertKu is offline
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Quote:
Originally Posted by Tad View Post
I would say don't use it. Like all boatbuilding questions the answer is not really black and white. Meranti is one name for woods from the family Shorea, which also includes Luan and Balau among others, what is currently sold as Philippine Mahogany is also from this family(total garbage). None of them have any rot resistance, not good for boats where mold and fugus starts at the drop of a hat. Yes, it can be used if totally and thoroughly coated with epoxy, and you are willing to take a risk. But is it worth it, only you can answer that.
Tad, could it be that we have a different kind of Meranti here, as I am puzzled why all the builders are using them here at the coast. Although I must say that some of the suppliers has Meranti which colour has become close to very light brown, instead of dark brown as from 20 years ago. Thus selection of the correct supplier is important. Most books come from Europe, Canada and the States. Their designs has wood names we cannot get here easy.
Bert
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  #325  
Old 04-17-2012, 04:03 PM
BertKu BertKu is offline
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Quote:
Originally Posted by masalai View Post
W
If I build again it will be in "marine ply" and sealed with a pre-coating of West-System-GRP on both sides and an epoxy glue, with fillets and tape reinforcing the build joins (NO SCREWS left in )... With multiple layers on the bottom and a couple of thin layers to the chine above the water-line... I feel that "CNO" will outlast my years on this earth - my preference for ply now is just a personal choice and not based on quality or suitability of material - I am not so concerned about a "weight penalty" of ply-cored vs balsa-cored... as has been said above - essentially the choice is yours...

- As a boat-building timber I like 'Kiri' or 'Powlina' (same thing) which is now plantation grown - maybe not mature enough for ply yet? . . . a search using "paulownia timber" yeilded the following as a sample.........

http://en.wikipedia.org/wiki/Paulownia

http://www.highpointtimber.com.au/

https://www.google.com.au/search?q=p...w=1920&bih=943 = pictures of kiri & products
The boatbuilder in our town who passed away 2 years ago, gave me the recipe on how to preserve wood. We have wood here which really need such treatment. One take a gutter, close it at both ends , fill it with a substance and soak it for 24 hours. Let it dry and use it. Non of his customers who traveled to hot and cold countries had any come backs. Maybe that is the route to go. Soaking the Red/Brown Meranti?
Bert
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  #326  
Old 04-17-2012, 07:15 PM
pdwiley pdwiley is offline
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Quote:
Originally Posted by BertKu View Post
Tad, could it be that we have a different kind of Meranti here, as I am puzzled why all the builders are using them here at the coast.
Big difference in outcomes between something exposed to blown spray/salt and the same thing immersed in salt water. You can't draw any conclusion WRT longevity between the 2 just because it's OK as a window frame.

PDW
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  #327  
Old 04-18-2012, 01:57 AM
BertKu BertKu is offline
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Quote:
Originally Posted by pdwiley View Post
Big difference in outcomes between something exposed to blown spray/salt and the same thing immersed in salt water. You can't draw any conclusion WRT longevity between the 2 just because it's OK as a window frame.

PDW
Yes, that make sense, I will go to the yacht club and chat to the sailors and see what they have to advise me on. There are a number of locally build yachts from Durban and Cape Town in the harbor. I understood that Meranti is sensitive for a) Lyctid Susceptibility of Sapwood ; Susceptible (source AS 5604)
b)Termite Resistance of Heartwood (inside above ground) Not resistant
(source AS 5604)

Back to the drawing board, however will we ever get termites on a yacht ???
I doubt it in this area. Lets see what the locals have to say.


Quote:
Originally Posted by BertKu View Post
Soaking the Red/Brown Meranti?
Bert
Bad idea I think, Miranti is too hard, have to be done in vacuum.
Bert
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  #328  
Old 04-18-2012, 02:09 AM
BertKu BertKu is offline
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Quote:
Originally Posted by masalai View Post

If I build again it will be in "marine ply" and sealed with a pre-coating of West-System-GRP on both sides and an epoxy glue, with fillets and tape reinforcing the build joins (NO SCREWS left in )... With multiple layers on the bottom and a couple of thin layers to the chine above the water-line... I feel that "CNO" will outlast my years on this earth - my preference for ply now is just a personal choice and not based on quality or suitability of material - I am not so concerned about a "weight penalty" of ply-cored vs balsa-cored... as has been said above - essentially the choice is yours...
I have figured that also out and will stick to Lloyd's approved French plywood. Thanks for the tip on removing nails and screws from below waterline. I was planning to immerse them into the wood and then seal it. But I take your advise.

bert
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  #329  
Old 04-19-2012, 12:34 AM
tugboat tugboat is offline
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I still think you will be fine regardless of what anyone else says if you want to go with meranti Bert--its tough stuff--just coat it with epoxy.west system...or similar.
you will be fine...oukume could work--so could joubert..not sure what else would even come close to those...remember that vid i showed you...!
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  #330  
Old 04-19-2012, 02:22 AM
BertKu BertKu is offline
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Originally Posted by tugboat View Post
I still think you will be fine regardless of what anyone else says if you want to go with meranti Bert--its tough stuff--just coat it with epoxy.west system...or similar.
you will be fine...oukume could work--so could joubert..not sure what else would even come close to those...remember that vid i showed you...!
It is actual quite cute. We have 47.330 odd forum members with 47330 - 1 (mine) views. I have thus to select what make sense and what is questionable. I think you are basic right and also TAD. I have thus decided to go to the local tree processing factory and ask them what it would cost to have the Meranti treated in their vacuum preservative process plant.

Whatever one does, one has advantages and disadvantages. If I ever have a fire on board, I will die from poison fume inhalation should I treat the wood. If I don't do it, I may have a hard time with all the creatures crawling into the wood and the seawater may rot the wood. However, I visited the yacht club and spoke to 2 people. One of them had dark red/brown Meranti strip outer around his hull and that was directly exposed to seawater. After 20 odd years, it still look good. All he said , it took some maintenance in using wood-stabilizer oil treatment, every couple of years.
Folks keep on giving me advise, I will shift and select.
Many thanks
Bert
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