Slipway material

[zuffen]

I have a slipway that runs from a boat shed into Lake Macquarie.

Currently it has extensively rusted 90lb rail line and it needs replacing.

The quote to replace it is $6,600.00.

I only use the slip to store a 125kg boat so it doesn't have to support a heap of weight.

I was thinking of fabricating it out of 75x50x3 box section and then galvanising it.

I figure it should last 15 or so years before it becomes a problem. By then I will be way too old to use the boat so that becomes my 2 sons problem.

One factor in its favour is it can be fabricated in 8metre sections and reasonably easily moved (they would fit on my boat trailer) and be bolted together whilst rail line in 6metre lengths will weigh around 750kg per 6 metre length and I'd need to move 8 of them! Then I have to bolt them together with fishplates and I'm not sure I can hold my breath long enough! Additionally I need to use some sort of "sleeper" to keep them in gauge.

I plan on using urathane wheels to reduce the impact on the gal.

Any thoughts on whether this is the way to go or alternatives in material/size ect would be appreciated.

I looked into stainless but there were too many problems in welding it and causing nickel migration.

[soundman]

how is the slipway supported?

is it run on a cement slab or on piers?

cheers

[zuffen]

In the boatshed it will be on a concrete floor.

Once outside the door it will go across a 1.5 metre concrete pad (to be laid) and then has to cross 2metres before it hits the bottom of the lake.

I plan on having welded legs and feet to bury in the lakebed to support the slip at 1 metre intervals.

The slip will only support a Hobie Cat so around 250lb or 120kg plus trolley at perhaps 25kg.

I think this is of sufficient strength but as always it's worth getting other, like minded, people's opinion.

[joe greiner]

I've built a garden railway, using pvc pipe for track. Narrow gauge, and movable track sections which latch together for assembly. Much simpler than bolts. Can easily support 250-lb on each carriage. I usually use it for moving heavy logs, and the locomotive is a work in non-progress. It's still night here, but I can post some pictures tomorrow. My track lengths are about 6 feet, but standard length of 20 feet (~6m) would likely be manageable, including cross ties. For wider gauge, shorter lengths and cross-bracing would be advisable.

Cheers,
Joe

[joe greiner]

Here are some pictures of my garden railway. I'll post something more comprehensive when I complete the locomotive.

The rails are pvc pipe, 1" nominal IPS. Sections are connected with over-center latches. The slot in the alignment dowel accommodates the bulged end of pop rivets attaching the latch. The extra holes were used in a previous connector design. Newer cross-tie connectors are placed away from the running surface.

Carriages were originally built to hold plastic buckets of dirt for crawl space excavation. I made a couple swivel plates to hold logs. The swivels allow passage along curved track. The carriage wheels were harvested from inline skates from garage sales.

I didn't actually use the railway for these logs, because the distance was too short to justify it. This setup was strictly for photography. I have, however, used it for much larger logs.

A more robust development may use all pvc instead of wood. Some sizes of pvc pipe telescope with one another (for the dowels), and partial pipe fittings could also be used for sleeper attachment.

I see no reason why this scheme couldn't be scaled up for your application. The pipe is certainly strong enough. Lightweight, portable track systems like this are also used for dolly tracks for cinematography. Mobile camera carriers are generally heavier than small boats, especially with one or two camera operators aboard.

Cheers,
Joe

[zuffen]

Our Australian sun eats poly pipe left exposed.

Additionally the wave action (we have up to 3" waves on the lake) would most likely knock it around too much.

I like your wheels. How do you keep them on the rails without any flanges?

I was looking at making wheels with a double flange from a large quantity of nylon material I obtained from our State railways. Same material as cutting boards and about 10mm thick.

I'm certainly open to suggestions.

[soundman]

plastic pipe is used in the film industry for dolly track...they run the carrage on either rollerscate or rollerblade wheels.

They way they get them to track is they mount two wheels at 90 deg.. both at 45 deg to vertical.

If you were to run plastic pipe......you would have to go with one of the black plastics.....high preasure black polly pipe might be the go.

OR

HFT electrical conduit

both stand up in the sun pretty well... but the pollypipe comes in continuous lengths so it would be possible to do it with no joins... but you would still have to come up with a streader system and tie it down.

I may just be simpler to go steel..... But I recon channel would be the go..and you just run standard tyres in the channel....on the cement you more or less just bolt it down.....from there you will need to weld spreaders in and support it however.

Having seen the renovation of a local boat ramp..... why not just run cement all the way down past the LAT point...there are a number of ways of doing that.....if it is slab all the way down you only need 1 track.. and that could be channel..and the trailer could remain unmodified and able to run on the road.

cheers

[joe greiner]

G'day, mates. Still daytime here.

Like soundman says, CPVC pipe or conduit is UV-stabilized, and more resistant to deterioration.

The carriages in the crate are stored with the tops facing you. Just beyond the nearest wheels, are plastic bottle caps attached to the undersides. They provide enough lateral support for guidance. On some mobile camera platforms I've seen, the wheels have a reverse crown, like the inside of a donut. And there are other standard wheels with a V-shaped notch on the rim to ride on angle iron with the open side down, and welded to flat plates. Pairs of wheels also work well, as soundman says.

Dolly tracks usually have folding cross ties, to collapse into side-by-side rails from rectangular to parallelogram to flat.

For your wider gauge, diagonal cross bracing could hold the spreaders in position. And bags of shot could be lowered onto the spreaders for ballast, with lines to floats for retrieval.

This might not be the perfect solution, but it's food for thought.

Cheers,
Joe

[zuffen]

We get up to 3' waves on the lake so I can't see the poly pipe surviving too many seasons.

I'll have another think about it and see if any other viable alternatives pop up.

I don't want to use any timber as it only rots away so steel is the obvious material.

I'd looked at using stainless steel but my welding skills aren't up to that.

[soundman]

Black high preasure polly is pretty damn tough stuff.....if you can nail it down well enough it should last plenty good.

cheers

[zuffen]

I can "nail down" the first 6-7 metres of the slip then the next 2 are suspended over low a seawall until it hits the lake bed.

I would need to support the 2 metres where it goes over the seawall then work out some way of "nailing it down" to the lake bed.

I thnk I need weight/stength to hold it in place and/or span the gap after the seawall.

Perhaps that why originally they used 90lb rail line.

[jatt]

I'd looked at using stainless steel but my welding skills aren't up to that.

I think the price would scare you more. As one of my steel suppliers recently said to me, "stainless is drug money!!". Dont recon stainless is that bad to weld myself.

As previously stated black high pressure poly is quite tuff. Maybe replace joe greiner's timber cross members with concrete blocks.

[zuffen]

The price of stainless doesn't bother me unduly. What it costs it costs. If you want it to last you need to put your hand in your pocket.

I have a problem making the poly pipe stretch over 2 metres without any support where it crosses the sea wall.

Still exercising my mind on this problem.

[joe greiner]

Word pictures have apparently become inadequate. Can you post a sketch showing a side view of the situation? Preferably with approximate dimensions and slope of the slipway, waterline locations, etc. Bridging the gap might be done with a separate support structure. Building the whole affair based on the shorter requirement isn't the way it's usually done, especially if it doesn't need to be removable.

Cheers,
Joe

[zuffen]

Sorry no photos. The slip is 100km away at the weekender.

The slip runs at a pretty constant angle of (approx) 15degrees.

The biggest problem is getting over the seawall and onto the bottom of the lake.

Additionally whatever I put in there must be heavy enough to not try and wash away or move with wave action.

Those two reasons are why I keep go back to steel in my thoughts.

I appreciate the ideas/suggestions so please keep making them.

[joe greiner]

The term of art is "marine railway," although they're not usually that steep. For larger boats, a motorized in-haul capstan or winch is needed; which you probably don't require - hand winch probably satisfactory.

A separate structure can span the gap between the sea wall and the lake bed. The rails can be attached above it.

Weight of the railway is not the only way to secure it. For permanent installation, helical ground anchors can be placed by hand. They engage a cone of earth, and the weight of earth provides the hold-down force. Similar devices are used for hurricane tie-downs for small sheds and mobile homes. Probably available at Bunnings, for all I know (Our version, Home Depot, has them last time I checked). They could be used on both the land and lake bed regions, if you can work in water up to about waist depth.

FWIW, the smallest boats I've dealt with were harbor tugs; the largest were Trident submarines. Larger than that, they're called "ships" instead of "boats."

Cheers,
Joe

[zuffen]

John,

We have a 3 phase winch with a 2hp motor and (I'd guess) a 20:1 gearbox on it so I figure I could haul out a good sized boat with it. We once dragged the rails up from the lake with it to replace two lengths that had rusted away.

I would like to keep the structure light and simple so spanning the gap with the rails fits that plan.

I was thinking of adding short legs with feet on the end that I could bury in the lake bed to stop any movement.

[ian]

If your boat only weighs 125kg why have a slip way?
would a submersible trolly with large wheels to ride on the lake bed be a better option?
I think I read that byou have a decent winch
After all I'm thinking of something like the large wheel trolleys used to move hobbie cats across sand modifed somewhat to look like a very large stair climbing trolley to get up the sea wall

[zuffen]

The slip joins the boat shed to the lake.

Using beach rollers (which I have) for the boat is impractical as the rails are in the way of it getting into the shed.

Additionally the entrance door is only 50mm wider than the baot so a slip will keep it all aligned.

Lastly it is rare to have a slip, boatshed and jetty on one block of land on Lake Macquarie. In our stretch of the lake there is one other amonst 50 or so houses.

Once you remove the slip, or it falls into disrepair you can't replace it. To get a new slip approved is like pulling teeth.

The value of a slip on re-sale is somewhere around $100,000.00 so it's certainly wrth retaining.

This block had 2 slips but the 2nd was removed before we purchased the block and we can't have two under the existing rules so the 2nd is gone forever.

[ian]

That last post about the planning regulations is probably the most important

I'd go with a like for like replacement -- that way no one can claim your installing a "modification" or "improvement" to the existing use