Lightest Yet Strongest Wood Possible???

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Bob Perkins
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Re: Lightest Yet Strongest Wood Possible???

Post by Bob Perkins » Wed Sep 12, 2012 3:49 pm

if you want a light boat - vacuum bag the layers and you will get one.
The boat is light.
and once you get it on top of the water, why does weight matter?

at that point it is prop size and rpm's - correct?

My boat is up on plane pretty fast. after that - rpms do all the work.
Not a naval designer -

I have not weighed my boat - but I estimate ~2400 pounds. 1000 of that is the motor.
You could save more weight there that the frames. I would not recommend changing the plywood.
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Bob Perkins

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jamundsen
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Re: Lightest Yet Strongest Wood Possible???

Post by jamundsen » Wed Sep 12, 2012 3:50 pm

Some pics of the Monte Carlo at G6 and one 8 days prior.
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photo3.JPG
photo2.JPG
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John Amundsen
Monte Carlo
Lakeland,Fl

Work tends to get in the way of boat building

CodyP
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Re: Lightest Yet Strongest Wood Possible???

Post by CodyP » Wed Sep 12, 2012 7:23 pm

No way! 454....how many horsepower? What did the boat weigh minus engine? What was the top speed? Cruising speed?

How well did the 454 fit in the engine bay? Room on sides? Easy to get to and work?

Thanks,
Cody P.
The dream will never become true unless you fabricate it yourself.

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mrintense
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Re: Lightest Yet Strongest Wood Possible???

Post by mrintense » Thu Sep 13, 2012 3:34 am

jamundsen wrote:I just launched my Monte Carlo at G6 for the first time last friday. It has a 454 in it and ran awesome.

Man oh man, you would expect a big ol hump on the top of your boat with that motor, yet she looks as clean as can be. Great work John.
Carl
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Crafting a classically styled Vera Cruise named "Some Other Time"

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jamundsen
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Re: Lightest Yet Strongest Wood Possible???

Post by jamundsen » Thu Sep 13, 2012 9:48 am

454 is about 375. Is not stock. Estimated boat weight all up is 3600 to 4000 pounds.
Engine is at a 16 degree angle. Fuel Injection would fit better. So would a down angle tranny. I raised the deck aft of the front cockpits 1 inch and so far no one has noticed. There is plenty of room under the hatch. The hatch was the hardest thing on the boat to build.
John Amundsen
Monte Carlo
Lakeland,Fl

Work tends to get in the way of boat building

CodyP
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Re: Lightest Yet Strongest Wood Possible???

Post by CodyP » Thu Sep 13, 2012 1:05 pm

jamundsen,

Thanks so much for getting on here. I wish I could see your boat! Pictures look absolutely incredible!

What speed can you get out of it?

Do your remember about how many board feet of Mohagony you used?

Also, how wide is your boat at the widest point?

Thanks again
The dream will never become true unless you fabricate it yourself.

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galamb
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Re: Lightest Yet Strongest Wood Possible???

Post by galamb » Thu Sep 13, 2012 6:14 pm

To keep your weight down, if you have decided on Khaya for the frames, stick with Okoume (Gaboon) plywood. Although a little more expensive it is significantly lighter than either Meranti or D-Fir (marine).

If you are fiberglassing (cloth/epoxy), use 4 oz instead of 6, 7, or 9 oz cloth where you can get away with it.

Keep your additional hardware to a minimum - for example Fortress makes an aluminum anchor at 4 lbs that has the holding power of a (steel) 9 lb version - you save 5 pound here and there and before you know it, you are 100 lbs lighter.

Go with LED nav/courtesy lights. They suck less power which could mean you can get away with one (smaller) dual purpose battery instead of a biggie or a pair. Ditto your electronics - if you don't need them or want them (but don't sell yourself short - being able to make 70 mph might "suck for you" if you can't listen to your favourite tunes - so maybe only going 60 with "born to be wild" blasting at a gigawatt might feel a whole lot faster) :)

When figuring out your engine/drive set-up check the weight as well. Just because motor "a" is 50 pounds heavier, if it will give you 30 or 40 more horses, it will more than make up for the added weight.

Unless you absolutely need anti-fouling paint, consider doing the bottom with a racing epoxy paint such as VC epoxy from Interlux (there are numerous teflon bottom paints out there). Hull drag is often overlooked in an effort to keep things light/fast. It plays a significant role. The "slicker" the hull, the less effort the engine will expend to push through the water = the faster you will go.

When you are done and on the water, don't carry too much "extra" stuff. If you are only going out for a couple hours, don't run with a full tank of gas. At 6 lbs/gallon a 30 gallon tank which is only half full is almost 100 pounds lighter than if it's topped up.
Graham

Yes, Plywood is "real" wood :)

A "professional" is someone who gets paid for their work - it doesn't necessarily mean they are good at it :)

CodyP
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Re: Lightest Yet Strongest Wood Possible???

Post by CodyP » Fri Sep 14, 2012 7:22 am

Galamb,

Thanks for the response!

What you just said is the direction I think I will end up going. Spending 3 times more for wood that is 14% lighter just isnt worth it. I could spend $2k on wood, drop $500 more on the motor and come out ahead, rather then $6k on wood (If I used Sitka) to cut 200 lbs of weight and a lower HP motor.

Years ago I use to work in a shop that made high performance sand rails (Dune Buggies), we would use lighter paint and less coats, light upolstery, cut any extra electronics that weren't vital, etc....when it was all done, we could cut 500-700 lbs of a car.

As to the hull.....in my opinion that is the single most vital part. The world I come from there is more art in the hull of a boat then any other part. Call me crazy....but I am strongly considering making some alterations to the hull, I just don't know enough of about this style boat yet. The deadrise is 6 degrees...I am thinking of changing that, thinking of changing the surface area, the more contact....the more friction....the more drag....means slower...

Do you guys think 350 HP would be enough for the Monte Carlo????

Thanks again.
The dream will never become true unless you fabricate it yourself.

rickplot
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Re: Lightest Yet Strongest Wood Possible???

Post by rickplot » Mon Jan 23, 2017 11:14 am

Actually the empress is the lightest and Strongest wood. It is also a hardwood.
Light weight
Empress wood is the lightest known timber other than balsa. It is also named the Aluminium of Timber. It is around two thirds of the weight of the lightest commercial wood currently being grown in North America, Costa Rica and Europe. Empress wood is a third of the weight of Oak and half the weight of Pine.
Strength
Empress wood has the highest strength to weight ratios of any wood in the world. Auburn University tested the strength of 18lbs p/cubic ft. against balsa with an average weight of 10lbs p/cubic foot.
Strength of modus rupture mor (psi)
Balsa…………….2800
Paulownia………5750 Source Dr. R.C. Tang, Auburn University
Plantation grown Empress is mostly knot free and holds nails and screws well without requiring pilot holes to be drilled. Both yellow poplar and white pine wood have proven to split before empress wood.
Conductivity
Empress wood is a very good insulator. empress constructed log homes are said to have twice the “R” factor as pine or oak wood. This temperature resistance serves to give the wood a high fire resistance too with ignition temperature approximately 400ºC, almost twice as high as many conventional hard and soft woods.
Other Empress Wood characteristics
Ideal for the boat industry.
• Low shrinkage;
• Very good dimensional stability;
• Resistance to insect damage;
• Resistance to fungal rots (but not to surface moulds).

I have done a lot of research on this amazing wood.

Nova SS
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Re: Lightest Yet Strongest Wood Possible???

Post by Nova SS » Tue Jan 24, 2017 7:42 am

With aluminium heads and intake on a BBC it weighs about the same as a SBC does.

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Bill Edmundson
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Re: Lightest Yet Strongest Wood Possible???

Post by Bill Edmundson » Tue Jan 24, 2017 8:39 am

If your going to get a 3500# boat to 60 mph, you'll need about 500 hp. At the same weight boat, 350 hp. will get it to about a 54 mph range.

If you cut 200#, you'll gain maybe 1-2 mph with the 350 hp. Two mph with the 500 hp.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
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Nova SS
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Re: Lightest Yet Strongest Wood Possible???

Post by Nova SS » Tue Jan 24, 2017 11:41 pm

ya diminishing returns kick in fairly fast when you want to go fast

boatsrea
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Re: Lightest Yet Strongest Wood Possible???

Post by boatsrea » Sun Jul 02, 2017 4:48 am

Iggy wrote: I've been really happy with my african Mahogany, its not too heavy and strong for its weight. I'd stay away from oak if you want to stay light, its strong but heavy by comparison to Mahogany.
Definitely agree that African Mahogany is the clear winner in terms of strength, weight and aesthetics. Fir comes in a close second but Mahogany is prettier.

Cyclone
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Re: Lightest Yet Strongest Wood Possible???

Post by Cyclone » Sun Jul 02, 2017 6:21 pm

I remember when I was looking at my plans for the boat it said to use 1" net thick material for the frames. It was also stated in the plans to finish the material as close to 1 inch thick as possible (7/8"), but do not go below 3/4" finished thickness as a minimum. The plans said the material could be white oak, mahogany, or spruce. I ended up using clear quarter sawn white oak. What was interesting to me was that had I used mahogany and finished it to 1" thick, the weight for a frame made of this material would be similar the same frame made from white oak that was finished to 3/4" thick. I would think that if the white oak was quarter sawn and 3/4 inch thick it still might be stronger than plain sawn 1" thick mahogany. The thicker mahogany would have the advantage of larger surface area contact to the planking and less concerns about compatibility with epoxy adhesive. Where I live the quarter sawn while oak is about half the cost of mahogany. The white oak grows locally.

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