75mm diameter Stainless tube for a bowsprit?

Oops sorry boss. I've used Aalco and London Metal Co. for Aluminium before but they both do stainless too. But I've always been dealing in more industrial quantities than you are looking for. Still might be worth a phone call.
Can I have my job back now please?
 
I could've walked downstairs and asked ...

I did ask if you were putting a downhaul on it

I have no way of knowing your design prowess ... same as you don't know mine

If your really nice I'll ask ... /forums/images/graemlins/laugh.gif
 
I am considering all candidates for the rebuilding of the specification review and customer response team.
However, my recruitment people say that I could replace you all for less than half the price by outsourcing to Home Office deportees who havent actually left yet. Also will save on pension and redundancy money, let alone the NI.
 
I speak from experience! Interested in beefing up some stanchions, I took 1.5mm thick 25mm OD 316 solid drawn tube and impaled it on a round bar which was a snug fit in the tube and gently tapered at the end to avoid stress concentration. Secured, I then applied my weight on the end. Yes it did bend but then Young's modulus was defeated and it kinked. You cannot straighten a kinked tube. Diameter to wall thickness in this instance is an awful lot more tolerant than 1mm wall on 75 OD tube.

Tell you what;- you buy him the tube and I'll bend/kink it.

Seriously, Durbin Metals in Avonmouth would supply I'm sure.
 
[ QUOTE ]
I then applied my weight on the end.

[/ QUOTE ]

That's not a fair test, regardless of whatever your weight might be!! /forums/images/graemlins/wink.gif

Stanchions are meant to work in unison; that is why we also have specifications as to how taut the lifelines must be. If they are correctly set up they can absorb the force of a crewmember thrown bodily at them; if the lines are slack, the stanchions would collapse like over-cooked maccaroni.
 
I like the idea for a bowsprit - Halberg Rassy's seem to use a bit of stainless tube for a cruising chute - about 1 metre overhang from the fixing point, curved downwards and looked very neat. About 2 to 2½" diameter SS but couldn't see wall thickness as it had a plate welded on the end.
 
Any rude observations about my weight are probably very accurate!

That really wasn't the point of my post. At the diameter to wall thickness ratio I employed, the tube still kinked albeit eventually. 75mm OD and 1mm wall thickness is a much more delicate combination especially when a length of 2.5m is involved.

Without wishing to digress even further, the test I did on the stanchions gave me enormous confidence in their strength. What you say about shared load is obviously valid, but if one on its own will take the shock load of a falling body, in concert they are most unlikely ever to fail. (They are also much taller than the "tip you over the side" trip wires commonly seen).

The bent stanchions and deck sockets I have seen, have all been inwards-leaning where the shared load argument falls down. Presumably these are the results of alongside collisions.

Lets put the lid back on the worm can now, eh? /forums/images/graemlins/tongue.gif
 
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especially when a length of 2.5m is involved

[/ QUOTE ]

I'd be supprised if the bowsprit is to extend 2.5m from the bow ... thats an f'ing long bowsprit and only really advised if you sharpen up the end and aim at someone elses beam!!

so come on the FC - give us an idea of your plans .... how much is it going to protrude by and are you giving it any lateral support?
Oh - and is it to be polished or matt?
 
Re: Battering ram

Well, here is a bit more....

The bowsprit forward of the bow roller only needs to be 400mm.
The bow roller section requires another 500mm
The anchor locker/lid requires a further 1000mm
The foredeck area aft of the anchor locker to create a sliding sprit arrangement needs to be 450mm
This adds up to a sprit length of 2.35 metres, which I thought would be an odd length to be asking for.
There will be a strop attached under the bow which will have a turning block through the end of the sprit leading back to the aft end, which will attach to a control line and locking feature. A secondary light release feature will allow the unlock and retraction.
Bow roller fitting has a full diameter nylon support bearing 75-100mm in length in a reinforced cup and support cheeks, with a restraining strop either side to create a triangulated restraint for sideways loading. This will also act as the inline restraint for hauling out.
Upward loading is thus taken through the bow strop and along through the tube to the locking feature, and thus into the deck.
The whole has the ability to flex and dampen sudden gust loadings.
The unresolved bit is the quick release and stowage as a whole so that I can use both sides of the existing double bow roller for 2 anchors, and easy access to the chain locker under. Bit more to do on the draughting front there.


This winters major project.
 
You have my sympathy ....

The "experts" are out in force on this one ......

YOU want a supplier ...

THEY want to design it for you !!

Good luck !!

Oh - I have excellent SS suppliers out here - but by time get it from Riga to Essex ............... sorry.

As an aside ... I asked for a mainsheet horse. SS 1/2 rod bent into wide inverted U. Washers welded along the horizontal part as stops for sheet block. Inverted U feet at bar ends to fit over transom gunwhale and bolts through.

Took them 3 days to make ... 1 day to fit. All in price was £6.

DSCF0828.jpg


6 years later still as good as the day it was made ...... very glad I didn't post on here before making and fitting !!!
 
Why not buy 5 metres while you're at it - then you can make the spare for the first time somene clouts it on the quay and just transfer the fittings.

Talk to the people who make rollover bars for racing cars

names like Saftey Devices, Roll-tec come to mind try and google them.
 
Jim,

I don't hesitate in recognising your superior design/engineering skills to my own....

However, I would have thought that the dynamic properties of saomething like Carbon Fibre would be better......?

Surely it would absorb the load better, with a less direct path to failure, and would be much lighter, which would be a massive benefit from a handling perspective, eg fitting and extending the thing....?

As an aside....

The strategy employed by Asymmetric dinghies to extend the pole may work for you...

They have a line fitted to the outer end, internally.... led back to a pulley near the mast base and then forward to another pulley near the bow and then back again to the cockpit... which allows the pole to be extended out quickly.... if this line was made circular, and the tail led back to the rear end of the pole, then pulling it in the opposite direction would retract the pole..... or more interestingly, if the line secured at the outer end, also formed the downhaul, then as the sail was retrived, pulling in the downhaul would also retract the pole.....
 
Thats it, suicide is the only option left......

Actually the pole is retracted by a restrictor on the tack line. As you haul it in, it brings the luff of the sail in until all is tight, then it rests on the lower turning block, the cam cleat holding the lock mech is released, and wind in the tack line some more, and it drags the pole back with it. Lock the cam cleat again to hold it in the aft position. Release sail.

Now, wrists, strychnine or a plummet?
 
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