Best Way To Do Lightweight Stanchions/Lifelines These Days?

[Chotu]

Originally Posted by Tupaia

This is 16-20 leaks just waiting to happen. No different than a multitude of through hulls. They need to be in preformed sockets, probably too late to achieve this, or deck mounted stanchion bases either with non cored solid deck pad sections or back plated on the inside.

I’m definitely not looking to create leaks.

Could you elaborate a little on the preformed sockets?

I figured glassing in the stubs would prevent leaks.

[Sherpa17]

5mm is the minimum according to ISAF, 6mm is a safer bet. Strength will be much higher than the equivalent 7x19 SS wire so you have some wiggle room.

I think uncoated 1x19 wire is a better choice.

[rslifkin]

Originally Posted by Sherpa17

5mm is the minimum according to ISAF, 6mm is a safer bet. Strength will be much higher than the equivalent 7x19 SS wire so you have some wiggle room.

I think uncoated 1x19 wire is a better choice.

Uncoated 1x19 is what I'll be using when I re-do my lifelines this winter, but on a 50 foot cat, that would add a lot of weight compared to Dyneema or similar.

[Carriage Boy]

If you end up going with something tubular that is also pultruded regardless of the material, be sure you understand the strength of that tube in the circumferential direction not just axially (which is most probably how the tube would be spec'ed).

If all the fiber reinforcement of the tube is running only lengthwise rather than wound around the circumference of the tube in some form then there is only the tensile strength of the resin keeping the fibers from splaying open when it's cranked over if slipped over a deck mounted post.

Similar to G-10 laminate sheet being very strong in X and Y directions but relatively easy to cleave open like layers of a ham sandwich if a screw is driven in from the side of the sheet.

[Happ]

Originally Posted by Chotu

I’m working with the fiberglass/carbon pultrusion companies right now on a big order for everything I need to buy in terms of pultrusions.

I was thinking I’d order my stanchions from them too.

My thought was to drill holes through the deck and glass (or mechanically fasten) the stanchions right to the bulkheads.

Then I’d get Dyneema and run it through the stanchions to pads at either end.

Is this a good way to go?

I was thinking hollow tubes for the stanchions. However, this could be leaky where the Dyneema passes through.

Thoughts on this?

The answer is quite simple its done all the time on carbon race boats. Hollow tubes on plates that attach to the deck. Have the stanchion built with a bit if the bottom opened for water drainage. Just like metal stations.

A second way to go is to make the stations solid and run the Dyneema through holes drilled in the starchion.

[b_rodwell]

This is a little off-topic. But it relates to a similar problem.

WHAT IS THE BEST WAY TO DO DINGHY DAVITS TODAY???

The engineering for davits today is truly horrible - small davit base, very high side loads, high bending moment at base, lots of additional weight at the back of the boat. Any ideas? Any implemented solutions?

Thanks,

Brian

[Happ]

Kato makes very good Davits. The are well supported and the loads are not that great. They even make an option for solar panels that raise the panels a foot higher for easier ingress and egress onto the stern.

[b_rodwell]

Thanks! Kato has a lot of good ideas. The smaller models address the issue of the small base; the larger models do not. There must be better solutions out there?????

Thanks,

Brian

[Vingt-Knots]

Sorry for the off topic response Chotu, but I have a suggestion for Brian about Davit options. I went with a pair of ‘Baby’ Carbon Fibre Davits from Atlas in the UK for my Moody 45DS. The attached picture should give a general idea. Mine have a SWL of 125 Kg each, but you can get thicker walls that will up the SWL to 250 Kg each. Mine weight in at about 14 Kg each. Mine also breakdown into two sections for easy storage onboard. I went with a white paint finish to match the boat. Might not work on all boats as the supports need to be embedded in the hull.

Just an idea.

Cheers

[Matt Johnson]

Typically the stanchions would be filament wound not pultrusion.

If you'd prefer solid stanchions instead of tubes, then just use a tube to create a socket through the deck just like we discussed with the stub. If you haven't finished the deck yet, you can glass then above deck for more strength (the most common approach)

Seal the bottom of the tube when glassing them and caulk when you install the stanchions.

Matt

[Ken Fry]

Originally Posted by Chotu

Thoughts on this?

I have pultruded stanchions (fiberglass/polyester) on the boat I'm building now. I used 1.25 inch OD tubes for the stanchions fitted into 1.5 inch OD sockets that go through the deck to glassed in brackets at their bases. The sockets are 6" deep, and each socket has a drain overboard, so that water that runs down the outside of the stanchion has a place to go other than sitting in the socket.

Some hand grinding and fiddling was required to get the socket size and stanchion OD correct. One can order true telescoping fits, but for mine, it was substantially cheaper to go with stock sizes, which are not guaranteed to telescope. Also, the stock sizes were cheaper from McMaster Carr than from the manufacturer, and come in lengths that can be UPS'ed instead of trucked.

My stanchions are topped with mahogany hand rails, but a lot of people seem happy with dyneema lifelines.

I might do rod bases for the other hull -- seems less fussy.

[Ken Fry]

Originally Posted by Vingt-Knots

Sorry for the off topic response Chotu, but I have a suggestion for Brian about Davit options. I went with a pair of ‘Baby’ Carbon Fibre Davits from Atlas in the UK for my Moody 45DS. The attached picture should give a general idea. Mine have a SWL of 125 Kg each, but you can get thicker walls that will up the SWL to 250 Kg each. Mine weight in at about 14 Kg each. Mine also breakdown into two sections for easy storage onboard. I went with a white paint finish to match the boat. Might not work on all boats as the supports need to be embedded in the hull.

Just an idea.

Cheers

I would want support at the bottom of the tube, at about the location of the bottom bearing. Otherwise, it is putting a bending load on the deck that the deck may or may not able to tolerate.

[Vingt-Knots]

Ken, You are 100% correct. Sorry I should have mentioned that, the drawing from Atlas just shows how it works in a ‘general’ sense. The final install details are up to the owner, or in my case a marine shop in Greifswald Germany that works directly with Hanse/Moody. Mine does have extra structural support near the bottom of the tube that laterally ties the tubes into the transom.