Less expensive products versus "marine grade".

[seafox]

Originally Posted by GMac

Back in the early 80's I built a yacht that was all with 5 min Araldite. Sure I didn't expect it to last forever as the lads were young and only interested in beer, girls and sailing, nothing else. Not to mention it was a full noise harbour screamers i.e build for pure speed with a sail area measuring 'just bloody silly big', wings and trapezes. 24ft by 12ft on deck and 4' 6" on waterline beam. Strip planked cedar she was. Called 'Disorderly Behaviour'

She's still sailing today and still very very quick.

Don't knock my 5 min Araldite, I think it's good and I'm now having a sudden burst of sweet nostalgia. Is that a 'Ohhhhh....' I hear from the crowd

Ahh but explain oh one of wisdom (that a bit too sucky-uppy or just about right

) his wife has to call him OB2Kenobe. He sleeps in his luke skywalker pj's. But dont tell anyone I told you.

[GMac]

I would like to complain at the way this thread is going.

1st I though my 5 min Araldite was good stuff only to have Gord show otherwise. It was all encased well with fibreglass so I suppose that's what made it last assuming the strip-plank is still actually glued together

And now Wheels running around in Star Wars pj's. Is that a picture fit for this forum or my mind? I'd suggest Mrs OB2kenobe maybe a brave woman and be able withstand such horrors but poor little me, I think not. Yeap, Seafox I think that should be kept very quite purely in the interest of National Security and the welfare of our worlds children.

I'll never be able to look at Princess Leah the same way ever again even if she was the hottest looking one of the lot. Opps... flashbacks again

[Alan Wheeler]

He sleeps in his luke skywalker pj's.

The worrying part is, when the hell did you see me in my PJ's.
8-0
Well 5 min alrildit has to be a heck of a lot better than the glue used to build one boat I saw. The boat was sold to a new owner and some months down the line, a few are's of ply were starting to buble. On closer inpsection they found the boat had been glued together with a waterbased panel adhesive. Stuff we in NZ would call "No-more-nails". But this one was specificly for gluing gib board(I think you US guys call it dry wall) to timber studs. The glue had either never dried, or in the damp environment, had broken down to a soft gunk that would not longer stick. I honestly think the original builder would have had better results with bluetack.(chewing gum like substance we use to stick posters to the wall with)

[seafox]

It was when you got up to check the springs early one morning. May the force be with you.

[seafox]

Hey Alan,
sitting on someones mooring in Maretai bay just near Tory West entrance. Been rubbish weather since we saw you the other day. Going to have a crack at getting home in the morning as we are out of library books.
Andy reckons he is coming over on Friday. Be a good adventure for Nick and him.
We will be back just before Easter.

back to the thread...

I find cheap fibreglass baths from Bunnings make excellent cheap dingys.

[Alan Wheeler]

I find cheap fibreglass baths from Bunnings make excellent cheap dingys

You too?!? I found some 2" dowel fits nice a snug in the drain hole and makes a great mast.

[seafox]

the best thing to do to the drain hole is fit a 2" plastic hose. Tail the hose out the transom of the bath. The water comes up the plug hole, through the pipe and the jet of water pressure pushes the bath along. Free power. It is Piethagorearse's theory or something like that.

[GordMay]

For every action, there is an equal and opposite reaction. Here's mine.

Which side of the triangle does the 2" hose represent?

Pythagoras's (Pythagorean) Theorem states:
“In any right angle triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.”


The Greek philosopher and mathematician, Hero (± 100 CE), demonstrated jet power in a machine called an "aeolipile." A heated, water filled steel ball with nozzles spun as steam escaped.

Sir Isaac Newton’s Third Law of Motion states:
"Every action produces a reaction ... equal in force and opposite in direction."

[dacust]

I've been in this forum for a few weeks, and I was beginning to despair, but finally!!! A thread with some really useful information. I've been looking for a cheap dingy. seafox provides the idea, Alan elaborates and Gord explains the science behind it. Me? I'm going to put it into action. I'm going shopping.

[GMac]

Oh O, Wheels, Gord and Seafox may have just discovered a whole new outlook on dingys or may have killed a forum member. Not sure which

[mikereed100]

Practical Sailor did a test a while back on "long term" (?) masking tapes. They found that the stuff that stood up the longest and worked the best was common black electrical tape. Also by far the cheapest.

[GMac]

That's good timing mikereed. I'm just about to use a pile giving my beasty a full makeover and not before time I must admit. That dodgy stuff that just won't let go after a day or so is really annoying, being very polite. We use pile of electrical tape at rope on all the ropes, work very well.

[Alan Wheeler]

The water comes up the plug hole, through the pipe and the jet of water pressure pushes the bath along.

I baffled a kid the other day with an explanation of how we stop the boat from sinking if we hit something and have a hole in the hull. I very simply said, you cut another hole the same size just below so the water can run back out. He eventually clicked on, but I must say it was a worry there for a few seconds.

[Stranded Mariner]

I am just looking at plywood, for the outfitting of my boat.
There's exterior grade plywood, and marine grade plywood. It's the same plywood. The word 'marine' though makes the plywood about 2.5 times more expensive than the exterior grade.

[GordMay]

Originally Posted by Stranded Mariner

... There's exterior grade plywood, and marine grade plywood. It's the same plywood. The word 'marine' though makes the plywood about 2.5 times more expensive than the exterior grade.

Exterior Grade is NOT the “same as” Marine Grade Plywood.

Marine-grade plywood is made entirely of Douglas-fir or Western Larch. The grade of all plies of veneer is B or better.
B-grade veneer may have knots but no knotholes.
A-grade veneer has no knots or knotholes.
Both A and B grade may contain wood or synthetic patches.
Panels are sanded on both faces or Medium Density Overlay (MDO) or High Density Overlay (HDO).
The maximum core-gap size permitted is 1/8 inch.
Its exposure durability rating is EXTERIOR and the glue used is a fully waterproof structural adhesive.

Plywood panels rated as EXTERIOR but not Marine, such as A-B, A-A or C-C EXTERIOR, may contain any other permissible species and contain C-grade veneer.
Unless specially improved, C-grade veneer is permitted to contain knots and knotholes up to approximately 1-1/2 inches across, and the inner plies may have core gaps up to 1-inch wide.

Notwithstanding, there may well be many applications where Exterior Grade plywoods may suffice.

The detailed description of veneer grades and Marine-grade plywood is contained in Voluntary Product Standard PS 1-95 Construction And Industrial Plywood.
Goto:
http://ts.nist.gov/Standards/Conform...oad/ps1-95.pdf

What some others have to say on Plywood construction:

The Elements of Boat Strength: For Builders, Designers, and Owners ~ By Dave Gerr
Goto page 179 etc at:
The Elements of Boat Strength: For ... - Google Book Search

Understanding Boat Design ~ By Ted Brewer
Goto page 86 etc at:
Understanding Boat Design - Google Book Search