More construction questions (slipper)

Why are people so obscure and perverse with their answers?

Use modern epoxies and I suggest that the laminated frame will stronger than a solid one.

Laminating makes complex shapes and bends easy to form, no question.

Glues have never been better - epoxy will outlive the wood if it is used and applied correctly!

There are many answers to some problems and sometimes more than one is correct!

Solid is good, laminating is also good and sometimes better...
 
I hope you have addressed your reply to the wrong poster! My reply is not obscure in the slightest.
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"Artificial intelligence is no match for natural stupidity"
 
What you've got to remember is that those plans are designed for the amateur home builder. The lamination is probably to get round the fact that the average amateur wouldn't have the time or facilities to build a steamer. It would be easier to get the curves required by laminating up the timbers on a former or mould. Which I assuming is what the drawings/instructions say.....no!?
 
You are building a slipper launch, not an ocean racer the water will have almost no effect on your boat . As I have said before they used to be built out of rubbish wood,and some have survived 50 years. If you are sterting with white oak you are allready way ahead of the norm.

Good luck with your build
 
Just because the fashion of the 30s to 50s made a slipper into a mass produced product doesnt mean i want mine to be made the same way . Its not going to be made to sell and the timber is costing next to nothing as i have and will keep getting over stock of timber . If i wanted to knock it up out of ply and get it done quickly i wouldnt be asking questions about it . Id like to build a quality slipper launch and your advice on boat building would be very welcomed .
 
Theres a product called paralam made around portsmouth way that is chipboard and glue , all the wood chips are long grained and its as strong as steel so they say . I used it in a night club for a bar around 5 years ago .
So straight grain laminated with the cups opposed will be better than a solid timber?
If i get a better section of timber , no visible cupping of the grain would that not be stronger ?
 
What you are referring to is ¼sawn timber rather than the modern planked or through sawn timber. ¼sawn would be my choice but I have made a lot of laminated, highly formed items over the years with timber from the outer planks - gently curved end grain.

Be careful using white oak that it has been properly seasoned and not kiln dried also a lot of american white oak arrives here at around 6% moisture which is too low - you should be looking at 20% before working it to avoid expansion problems. - But there again, you are a carpenter (or is it a joiner) so you will already know this.
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"Artificial intelligence is no match for natural stupidity"
 
"But there again, you are a carpenter (or is it a joiner) so you will already know this."

Unfair assumption. I know several highly skilled cabinet makers and carpenters. I met them again at a BarBQ last weekend, and we got onto wood supply and boat making. They had little idea of issues involved in boat building, normally striving to keep their wood dryish, and were interested in the issues around electrolytic activity etc.
 
Take a nice whippy spruce tree , slice it down the middle, invert one half end for end, glue it up (solid or hollowed) and you get a nice wooden mast. Chippys and boatbuilders don't go out of their way to make more work ,yet that has been the preferred way to build a wood mast for the last 50 years,before epoxy glues came along.

Second point ,basic difference between a structure built by a chippy and a boatbuilders boat is that the former is designed to be stiff and strong enough for the job,the latter will be ditto PLUS able to bend and yield at all the joints ,where necessary,recognising that that's the only practicable way to bung a load of sticks together on a structure that is at times only partially supported as it goes over the waves out there on the oggin.
Third point . Forget all of the above...
you are using epoxy right ? So the ''wood'' is basically a filler for the glue layers ,as glass is to resin in grp(kind of sort of)...so long as everything is sealed you could build your slipper or replica viking longboat from cardboard and used lolly sticks(see recent thread 'bout that ).
Re using solid wood for 36x100hog ,etc . Fine if you have access to good straight grained stuff and not slash sawn ,warped,twisted bit of kiln dried imported rubbish. Otherwise ,you're scuppered and its laminations all the way ,which is useful imho if you want to 'lock in' a curve to the finished component.
Scuppers -drain holes around the deck edge coamings to let water drain back into the sea.
Piccies,piccies.Why not post a pic or scan of the drawing.if not a copyright issue with the designer.!
Get a copy of one of the Gougeon Brothers epoxy (westsystem) books ,they started out building and racing iceyachts before becoming boatbuilding gurus.
Great winter project ,by the way ,enjoy !
 
Your right there Brendan . I have little idea of the stresses moisture content or any other problems that involves timber in boats . I too like to keep my timber dry and my experiance of structual timber is limited to house building and the like .
Any Oak i have is left over from building fitted wardrobes or making doors and windows . As for the paralam being as strong as steel , it was designed to take the place of steel in buildings . It has been tested to take the same amount of stress that a steel can take but is a lighter product .I used it as a bar top because it looked good .
 
<<Many moons ago I wuz told 'fools build boats for wise men to buy'. If you want to go mad or bankrupt take up boat building>>

This must be incorrect, having built a few and lost only a few grand I would have to s a y ....

Excuse me I have to sign off, Lord Nelson and Napoleon are at the front door.
 
<<Whats a scupper do ? they are optional>>

Scuppers.--
Apertures cut in the bulwarks or waterways to clear the deck of water.


They help to drain the cockpit, good idea to include them as they will let rainwater out and drain when cleaning up, as well saving you a problem should you ever get swamped.

Avagoodweekend.
 
[ QUOTE ]
Your right there Brendan . I have little idea of the stresses moisture content or any other problems that involves timber in boats . I too like to keep my timber dry and my experiance of structual timber is limited to house building and the like.

[/ QUOTE ] There speaketh a wise man! - Your timber for boat building should be in the range 15% to 20% moisture not the 8% to 12% you are probably used to working with.

If your oak has been milled after seasoning/drying you will have removed the hard "case" Years ago it was common prictice to tie oak logs in a running stream to put moisture back or increase the moisture content before working into a boat. Get out your moisture meter and check your timber and if necessary stack it and soak it for a few days and then allow to air dry. Stay away from kiln dried timber unless you are going to resaw and mill the timber.
One of the reasons for laminating sections is you have better control over the item as you can select the timber to use. Solid sections are prone to splitting and usually have internal stresses which are relieved by machining the thin laminates (4~8mm) also greatly helps steam bending.

Be careful steaming oak as if you over heat it or steam it too long it will become brittle rather than "rubbery"
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"Artificial intelligence is no match for natural stupidity"
 
An interesting book is "strength of Materials" or why I don't fall through the floor by Professor Gordon. I think above is correct but its 30 yrs ago!

Now if my memory is correct:-

One of the interesting things mentioned in the book is that trees grow prestressed with tension on the outside and compression in the middle as when they are blown and bent by the wind they fail if compression occurs near the outside causing vertical splitting. So nature caused the outside to start in tension and it had to bend quite a lot before compression occured.

This was discovered empirically when bigger ships required bigger masts and spars than could be obtained naturally from one tree trunk. They cut trunks into sections and bound them together with ropes and hoops to make the bigger diameters. The shipwrights then found that the bigger diameter was often weaker (when subjected to bending)than a smaller diameter but "natural" piece of timber.

My understanding of theis is that for any given wood it is strongest when subjected to bending forces if it is cut from a natural piece of timber of the same diameter, hence once you shape it say to be rectangular or just a segment of circle you loss a lot of the natural strength.

Apologies for any mistakes in memory or deficiencies in explanation.
 
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