Termites won't go near it
OR carpenter ants
https://www.youtube.com/watch?v=t7aKgR7hcpE
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Termites won't go near it
OR carpenter ants
https://www.youtube.com/watch?v=t7aKgR7hcpE
I see you have been very busy doing some calculations and testing!......:D You will be just fine even with a 400R......;):D Looking good...:thumbsup:
OR just make the transom out of 2" thick steel. Then no questions!
Remember, even Wood has some squish when you tighten down the bolts. There's really not an issue if it has a little squish - It's not like it'll soak up water and ROT ! it's Foam afterall!!!
I knew thinking would get me in trouble......NP, seriously, this looks good. Your bench test results show that the "502 lbs of compression capacity" is way below the actual compression strength of your materials. That 502 number alone was the basis of my concern and math comments - not the use of foam of which I have absolutely no experience with. I was afraid we were all forgetting the clamp load that threaded fasteners impart on their clamped materials and those leveraged forces imparted by the propeller 20" away from the fulcrum where attachment is managed by two small 1/2" bolts through a transom. I'm enjoying the photos! The work is awesome and your cosmetics are some of the best I've ever seen. Keep them coming! Gordon
"No worries Mate" ;-) The 502 number, right or wrong was a guesstimate on how much a 1 3/4" washer spread the load. It was not attached to anything in general. the numbers you seem to be working with are maximum or fail numbers, I have no intentions of tightening the 4) 1/2 " bolts until the transom collapses or the bolts break. The force you are referring to is created by the prop, it is pushing on the transom bottom (load is spread by aluminum plates and lots of layers of glass) the opposing force is trying to pull the bolts apart @ the top, of the transom. (load is spread by washers, 1/4" glass splash well. 1/8" inside transom wall, 2+ inches 80 lb foam and multiple layers of cloth & resin, 1/8"+ outside transom wall) I'm thinking the tensile strength of the stainless bolts might not be high enough.Quote:
Originally Posted by Gordon02
I have absolutely no fear of the transom failing, it is "Strong like Bull"
I don't understand why you want to use "ultimate" numbers, the bolts only need to be snug + plus 1 or 2 hundred pounds clamping force.
4) 1/2" x 4" aluminum bolts is what Johnrude supplied in 1966 to hold the 80hp motor on.
Again, thanks for your Kudos and concern, and making me re-think some of my values.
( it's probably a good thing I'm not a rocket scientist) ;-)
A famous guy once said: stand back and watch this, "hold my beer"
A guy named steve 1 had some real world testing no's for balsa and foam with varying types of glass and thicknesses. His results were astounding to me. I wish it was still up on here and he was still around. There has been treasure troves of info lost over the years. And the physicals are for the foam only, not for laminated material. They have built 120' minesweepers out of divinnycel.
NP, you finished yet! Enough yappin!
Just know this when you are questioning the limits of Foam cored laminates. I have flown aerobatic aircraft with foam cored, multilayer composite wings that put much higher forces across their span at load levels exceeding 6Gs.
I think your sub 200hp motor will be fine in your lifetime.
...Glad you made the switch. Wish more people would do the same. There is no substitute.:thumbsup:Quote:
Originally Posted by NICE PAIR
Baltic birch marine ply +
African Okume Mahogany marine ply ++ Lighter weight!Quote:
Originally Posted by FMP
Ha!Quote:
Originally Posted by FMP
Attachment 424364 glassed a couple more floor panels (gonna need them some day.)
Attachment 424366 1st lamination of the keel to transom knee. (using left over vacuum bricks from the Skater build)
Attachment 424367 layout dimensions for new splash well back wall.
Attachment 424368 1st layer 1700 bi-directional.
Attachment 424369 4 layers ... lunch time.
Attachment 424370 8 layers ... goin home early. :thumbsup:
Quote:
Originally Posted by FMP
DivinnyCell foam 80 psi +++ lighterer :DQuote:
Originally Posted by home made tunnel
That curve might have been troublesome getting ply to conform. Only one that foam needs to impress is you.
You win - 4x8 sheet of 1/2" is only 8 lbs compared to my okume 37 lbs. Birch is 49 lbs !Quote:
Originally Posted by NICE PAIR