Lightest Yet Strongest Wood Possible???

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CodyP
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Lightest Yet Strongest Wood Possible???

Postby CodyP » Tue Sep 11, 2012 7:03 am

Hello all,

So this is my first post here....To start off, a little bit about me.

I grew up out west, boating Lake Havasu, Lake Powell, Lake Mead, Lake Tahoe, etc. I started driving when I was around 8 (I am 30 now), behind the wheel of high performance power boats. Over the years I have grow custom to boats that easily exceed 100 mph, cruising at 80 mph or 90 mph in a boat that rides like a cadilac is common ground. My families current boat is a 30' Eliminator Daytona with two 500 HP EFI motors.....

Long story short, it is time for me to go my own way with my own boat....However, dropping 150K in a boat comidically enough....IS NOT AN OPTION. :lol:

So I decided to go the opposite direction, get a classic, cruise the water, and enjoy life. That is why I am here, like most of you, I am going to build that dream.

So...my first question:

I am going to build the 24.6' Monte Carlo, I am guessing I will put a small block in it, most likely a rebuilt 350, possibly around 300 HP (or more if the boat can handle it). With that being a bigger boat, a heavier boat, using the lightest yet sturdy wood is the name of the game. In boating, every pound counts! I am hoping I can build this boat to hit 65 MPH, not that I will push the boat that hard, but I want to be able to cruise at 45-50 with plenty of head room, so the engine isn't pushing it's limit.

What wood do you guys like for LIGHT & Strong??? Again, every pound I can cut counts...


Thanks all!,
Cody P.
Last edited by CodyP on Wed Sep 12, 2012 12:51 pm, edited 1 time in total.

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Iggy
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Re: Lightest Yet Strongest Wood Possible???

Postby Iggy » Tue Sep 11, 2012 9:45 am

Thats a bit of a tough question. 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.

You'll find this Glen-L article helpful:
http://www.glen-l.com/wood-plywood/bb-chap5.html

Sitka spruce, if you can find it, is probably one of the best weight/strength ratio's, however its not the best for rot resistance, so I would make sure I seal it up good.
Ian (aka Iggy)
My Malahini Build

CodyP
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Re: Lightest Yet Strongest Wood Possible???

Postby CodyP » Tue Sep 11, 2012 10:20 am

Thanks Iggy!
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???

Postby galamb » Tue Sep 11, 2012 2:12 pm

Agree, the Sitka Spruce is right up there (weight wise/strength) at 28lbs/cubic foot, but depending where you are/available suppliers it can be "VERY" expensive.

Also favour the African Mahogany (Khaya) - at 32lbs/cubic foot it's 2lbs less (per cube) than genuine mahogany, very easy to work with and readily available, often times as a "bargain" compared to other species.

(my next built will utilize Khaya for all the frame work - I like it that much)

Douglas Fir (34 lbs/cube) is equavalent to genuine mahogany in weight and (maybe) a hair stronger. I used this for my frame material. It's easy to work with but splits easily which means lots of care when bending it and lots of "predrilling" to ensure that fasteners don't split it (which still happens anyhow). The major advantage of D-Fir is that it tends to be the most economical of all suitable woods (if you are buying from a retail supplier), but even given that, like I said, next time I will pay the 20% higher premium and go with the Khaya (I probably busted/replaced 40 or 50 bucks worth of Fir which would have put the cost on par).

One other note - the Khaya is way way "prettier" than either the spruce or fir, so it you plan on clear finishing, pick a pretty wood and if you don't mind spending (a little) bit more and are looking for a great natural look, check out Sapele (pronounced Sa-pell-eeee), an african hardwood (but heavy in the low 40lb/cube range) or Light Red Meranti (there are lot's of Meranti's, including Dark Red and Yellow - stick with the light), a tropical cedar (about 32lbs/cube) which is more often seen as marine plywood but is also readily available, reasonable and excellent to work with in "board" form.
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 :)

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kens
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Re: Lightest Yet Strongest Wood Possible???

Postby kens » Tue Sep 11, 2012 2:46 pm

Sitka Spruce is the winner as far as strength/weight ratio.
Mahogany is the winner as far as price, strength, weight, and all things considered.
If you want to save weight, oak & ash is not an option.
Southern cypress, Spanish Cedar, might be considered.
For a light plywood in the layers, Okoume is the way to go.

You might hit your 65mph idea if you pay close attention to your weight and workmanship.
There is a Riveria with a 350 mpi bumping 65mph built off the stock plans with mahogany.

The Monte Carlo can handle a BBC.
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

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Roberta
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Re: Lightest Yet Strongest Wood Possible???

Postby Roberta » Tue Sep 11, 2012 3:19 pm

Dark red Phillipine mahogany for framing, planking and battens, Joubert Okoume plywood for sheathing and cold molding, White oak for keel, and African mahogany for shears and chines. JMHO :D

Roberta :D
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

CodyP
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Re: Lightest Yet Strongest Wood Possible???

Postby CodyP » Tue Sep 11, 2012 5:02 pm

Kens....BBC, Big Block Chevy???? I LIKE the sound of that.....Imagine that baby! BAM!

Have any of you guys worked with White Pine??? I have been reading that is often used in Airplanes, very strong and light.

Also, anybody worked with this new bamboo junk that is going around???? The word is it is feather light, and 100 times stronger then anything else....

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

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

Postby Bill Edmundson » Tue Sep 11, 2012 5:19 pm

For boats no white pine. Southern Yellow Pine is very similar to white oak, strong, heavy and rot resistent. SYP was often used for tall ship mast. It slow growing and straight grain.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

CodyP
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Re: Lightest Yet Strongest Wood Possible???

Postby CodyP » Wed Sep 12, 2012 8:00 am

Bill,

Thanks for the help. Also, I just realized, your Tahoe is one of the boats I have been referencing for ideas in a build....GOOD LOOKING BOAT!

So as I am finding....Sitka Spruce is two things....Almost impossible to find....and bloody EXPENSIVE :cry:
The dream will never become true unless you fabricate it yourself.

CodyP
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Location: Nashville, TN

Re: Lightest Yet Strongest Wood Possible???

Postby CodyP » Wed Sep 12, 2012 9:52 am

ok.....STUPID QUESTION....but I have to ask....

Anybody build the frames with Plywood? Or is that just a disaster waiting to happen?

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???

Postby galamb » Wed Sep 12, 2012 11:09 am

There is much debate and many opinions have been written on using plywood for frames.

The overwhelming concensus is NO, not in a hard chined boat.

But then again, a couple of years back I saw a small runabout. It was 15 years old at the time and it looked amazing - wood was perfect and the boat is used regularly.

It was built "completely" (frames, seats, planks, decks etc) from RED Oak.

Ask "anyone" and they will tell you that Red Oak has no place in boat building.

But I still wouldn't use plywood for the frames. Glen-L's boat plans were designed for lumber frames and it's strength properties are oriented alot differently than plywood (compressive strength, strength perpendicular to the grain, on and on) and while there are some CNC kit boats available that use plywood, they were engineered that way.

If you cut a frame from plywood the weakest point would be right where you would set your chine - which in hard chine construction is the point where you need "significant" strength (second maybe only to the keel), whereas in a rounded hull, if the frames only supported numerous battens tightly spaced, you could easily get away with it...
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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Location: Nashville, TN

Re: Lightest Yet Strongest Wood Possible???

Postby CodyP » Wed Sep 12, 2012 1:07 pm

aaaaaaaaaaaaand another question!

I am guessing once I buy plans I will find this.....Does all of the wood for the frames need to be Qtr Sawn?

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

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Roberta
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Re: Lightest Yet Strongest Wood Possible???

Postby Roberta » Wed Sep 12, 2012 1:17 pm

Quarter or Rift sawn is best for framing, chines and shears. Flat sawn is fine for keels and battens. Grain doesn't have to be perfect, just watch out for gnarly looking grain patterns in either.

Roberta :D
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

CodyP
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Location: Nashville, TN

Re: Lightest Yet Strongest Wood Possible???

Postby CodyP » Wed Sep 12, 2012 1:40 pm

So just did some numbers.......

Sitka Spruce is coming in at around 100% to 150% MORE $$$ then African Mohagony and weighs 14.6% less.

So on a boat that is projected to weigh 1400 lbs, if I spent 100% to 150% more for lumber, I could cut 196 lbs off the boat. Why not just dropp $500-$1000 more in a motor to make up for the weight, and still come out WAY ahead????

Which as you all know, if you are in your boat with your 196 lb friend, and you are running say 60 mph, your look at your friend and say "Hey tubby! get out!" he jumps overboard.....

Your now 196 lb lighter boat will maybe increase in speed by 2 or 3 mph.....4 mph if the stars align and little angels give ya a push.

CONCLUSION: Sitka Spruce ADIOUS!!!!

What ways have you guys cut or know how to cut weight in your boats? No stereo, no amps, no railing? Finish's? Thinner vaneers on the outside?

:shock: (Thats my pondering face)
The dream will never become true unless you fabricate it yourself.

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jamundsen
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Re: Lightest Yet Strongest Wood Possible???

Postby jamundsen » Wed Sep 12, 2012 3:29 pm

I just launched my Monte Carlo at G6 for the first time last friday. It has a 454 in it and ran awesome. I just loved it. We did have some overheating issues to overcome but the boat was great. I dont think weight is an issue. I used mahogany for everything except the plywood sides which was okume 4mm plywood.
John Amundsen
Monte Carlo
Lakeland,Fl

Work tends to get in the way of boat building


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