Things I wish I knew about boats.

[Don C L]

So my wife asked me, since she does not take kindly at all to my lifelines that flop around when you grab them, "why don't more boats have railings that stay put?" In other words, rigid railings... and I could not answer that, I cannot think of a good reason why not... I don't know, aesthetics?... but I confess, I like the idea!
Secondly, after trying to help someone with adjusting a prop shaft a while back, I wondered aloud to mechanic, why don't they make prop shafts with u-joints so you don't have to be 4 feet tall with arms like Popeye to crawl back in there with a feeler gauge? (He didn't know) Or do they and I just haven't seen them yet?

[newhaul]

Originally Posted by Don C L

So my wife asked me, since she does not take kindly at all to my lifelines that flop around when you grab them, "why don't more boats have railings that stay put?" In other words, rigid railings... and I could not answer that, I cannot think of a good reason why not... I don't know, aesthetics?... but I confess, I like the idea!
Secondly, after trying to help someone with adjusting a prop shaft a while back, I wondered aloud to mechanic, why don't they make prop shafts with u-joints so you don't have to be 4 feet tall with arms like Popeye to crawl back in there with a feeler gauge? (He didn't know) Or do they and I just haven't seen them yet?

Don the rigid rails are not on most smaller.sailboats.due.to weight .
As far as the prop shaft . Its called a flex coupling
PYI Inc. | R&D Marine Drivetrain Solutions

[Don C L]

Originally Posted by newhaul

Don the rigid rails are not on most smaller.sailboats.due.to weight .
As far as the prop shaft . Its called a flex coupling
PYI Inc. | R&D Marine Drivetrain Solutions

AHA! So that flex coupling precludes the need for adjusting completely?

[newhaul]

Originally Posted by Don C L

AHA! So that flex coupling precludes the need for adjusting completely?

Not completely heck you have to be close with a standard u joint as well.

[Lepke]

If you fish, flex couplings make noises that bother some fish, but a proper alignment doesn't. A single u-joint needs almost the same aligning effort as no u-joint. Dual u-joints, even in alignment make noise.
Just some things I learned commercial fishing and repairing fish boats. It's one of the differences between people that catch a lot of fish and those that don't.

[UNCIVILIZED]

Fixed pushpits, pulpits, & railings cost a good bit more than do lifelines, & in many regards are more fragile. Consider what happens to lifelines when the boat presses up against something hard. Usually there's enough give in them that no damage occurs, or at worst a stanchion or two gets bent. And stanchions are cheap & easy to swap out. But if you nudge anything that's either solid, or heavy with railings, it'll; dimple them, bend them, fracture them, rip them out of the deck, & or rip out piece of the deck along with fully destroying them.

And of course dimpling or bending the tubing means that you have to replace that whole section of the railing, as well as probably redoing some welds elsewhere. Plus, those kinds of loads on railings can destroy the bedding compound where they meet the deck. Or even damage the hull to deck joint, if the railings are stout enough.

Then there's the extra weight up high which railings add. And it's no small thing, especially on boats your size. As it'll make the boat roll more, in addition to raising her CG enough so that she's more knockdown/rollover prone.
Plus, it's quite common not to notice problems with railings until they're about to fail, or the welds/joints have already failed. Where with wire, you notice the broken or rusting strands pretty much right away.

DO NOT use coated wire for lifelines regardless of how tempting it seems, for exactly this reason. You can't spot rust or broken strands until the wire is so damaged as to have but a fraction of it's original strength. And it's weaker than uncoated wire is to begin with, as the metal part has to be thinner for the stuff to fit through the holes in the stanchions when it's installed.

One other thing is that on sailboats it's common to have lines like jib sheets, & spin sheets & guys winding up pressing up or down on the lifelines with a good bit of force, before someone gets around to releading said line in order to take the load off of the lifelines. And since metal tubing, as well as it's welds doesn't take repeated cyclical loadings as well as something flexible like wire does, it's much more prone to damage from this kind of thing. Ditto just the loads imposed on it by someone pulling on it hard when climbing onboard.

Plus, when you put a load on the lifelines, such as when grabbing them to step on or off of the boat, the load gets spread out to all of the stanchions, as well as both pullpits. Which reduces the point loading on things. Which is the reverse of what happens when you grab a railing. With them, most of the load goes into the welds on either end of that section of the tubing. And into the 2 vertical sections of tubing which connect it to the deck. Ergo it's service life will be a lot shorter unless it's made using super beefy tubing (pipe actually). Which adds to cost, & especially to weight up high (the boat's CG).

And picture falling onto/into lifelines vs. railings. Which one do you think has less stretch & is more prone to fail catestrophically. Especially after being subjected to millions of flex cycles as the boat changes shape with each wave that it passes through. That flexing is tough on stainless welds, at every & all joints.

BTW, ever price custom stainless work? Go & check, & you'll better understand more of the why behind railings being uncommon. Even were it mechanically/structurally practical to add them to recreational sailboats, the addition to the selling price of th boats initially would be huge.

[UNCIVILIZED]

PS: When racing, you can't hike for s**t, if at all, with railings (vs. wire): Nuf said. AKA it's more than enough to make you lose any & every race.
And the vast majority o cruisers & weekend warriors want boats that look like racing boats, even though they don't race. And or it's well known that feature X doesn't work on anything but a purely racing hull, etc.

[IslandHopper]

Re solid s/s railing, One of my favourite manufacturers, Amel, has been building boats with solid rails for years and aesthetically look fantastic and are solidly built, lean on them or pull yourself onboard, no problems at all... I'd have one in a heartbeat....

[CaptRory]

Not so long ago, sailboats did not have lifelines or anything. Look at boats without them and they are much more aesthetically pleasing. One would rig "man ropes" before a blow. You shouldn't be hoisting yourself or pushing the boat around with them because you cause the stanchion to work which causes leaks and crazing. I would add to what others have said about u-joints with they create friction and eat horsepower and one more thing to break at sea.

[Cheechako]

I would guess rigid rails are not used mainly due to cost and difficulty of fitting them well. They are used on powerboats a lot. Deck fittings are an issue on fiberglass boats as well. with that big rigid rail, the fittings attaching to the deck need to be very strong. A lifeline absorbs some of the shock load.
When we built aluminum power boats welded railing all around was very time consuming.... but we did it.
I always liked the stern pulpits that were rigid extending forward of the companionway. Good compromise. You could step out of the cockpit to go forward and grab that secure rail until you are stable on the sidedeck.

[TrentePieds]

I have often thought that when my ship comes in - if ever - and I can afford new construction, I would specify a short intermediate shaft with a Spicer CV joint at each end. Stuff straight out of the Austin Mini of the early 1960s.

Such a set-up would totally eliminate the usual alignment problems permitting alignment deviation of up to 7 or so degrees while maintaining balance and constant velocity. Ne plus ultra :-)!

The CV joints you find in more modern FWD Chryslers might do the job just as well.

TP

[a64pilot]

Weight of rigid rails really insignificant. I replaced my lines in the cockpit with rigid tubes, and they are surprisingly light, however strong enough for me to stand on them if done near a stanchion, and strong enough to mount a 100 lb outboard on. My guess would be that tubes add maybe 5 or 10 lbs to a 40' boat, but do give you a LOT more SS to polish.

The only true flexible coupling that I know of that alignment is not an issue, yet will also work as a thrust bearing is Brunton's Sigma drive. There are CV joints for boats though that have two CV joints and a thrust bearing, if you have the room and money, they ought to be nearly bullet proof too.
Brunton didn't invent anything , Google an Rzeppa joint and that looks an awful lot like a Sigma drive, but that's good as the Rzeppa joint has decades of use proving its robustness, it's the U joint if you will for the front axle of large Military trucks
http://www.bruntonspropellers.com/sigmadrive/

I have one and can attest that it works, although I aligned my shaft as perfectly as I could prior to installation as that is just the right way to do things. However as all engines move around a little on their mounts, the Sigma drive should allow this movement to occur without putting anything in a bind.

[Scaramanga F25]

My preference would be a thrust bearing to a bulkhead forward of the cutless
and packing to a CV joint.

[zeehag]

it is not the weight but the flex. boats flex while sailing. rigid rails do not. no lifelines is perfect as they are not designed to be life saving devices but edge feelers. they are there so you know where the edge is. the lifesaving device is your teakwood grabrail on coachhouse roof.

[NevisDog]

Zeehag, I'd say you've absolutely nailed the lifeline/rail issue.