Cradle pads?

[Bodach na mara]

Two points here:

1. Why use anything on the pads? Don't ypu put wedges between padsd and hull Eamonn?

2. Osmosis CAN seriously weaken a hull. I saw a Westerly (you know, the type built like a brick outhouse with a thick layup) hull with holes that had been blasted right through by enthusiastic use of a sand-blaster. The hull behind the gelcoat had the consistency of chalk in the places affected, and areas of unbound glass reinforcement.

 

[jwilson]

Can you give a citation (evidence) for this please ? I have never seen square patches of osmosis.

I have seen patches of blisters where carpet pads have been, also seen a line of blisters where a carpet-lined hull support was on a trailered boat.

 

[Seajet]

Wotayottie & Tranona,

good points !

The boat I saw with osmosis via carpet pads was a Frigate 27 belonging to an erstwhile chum, the boat seemed to have a visibly eggshell thin, hard & brittle gelcoat; I thought the same of the Carter 30 I had, maybe a 1970's thing ?

The mention about plywood delaminating inside rings bells; when we were flight testing the Harrier II GR5 aircraft, people were rather worried about the carbon fibre bits, just like plywood an external impact can leave an almost indiscernible mark, but be shattered inside.

Nowadays there are ultrasonic test kits, but in 1985 they painted the aft fuselage white to show any 'link strikes' from the gun, then hopped around worrying if there were any!

I'd be very circumspect about a plywood cruiser, and am not a fan of carbon fibre for military equipment either, one of those things which is fine in peacetime when not taking knocks...which goes for yachts too, at least in my ham fists...

 

[ex-Gladys]

Can you give a citation (evidence) for this please ? I have never seen square patches of osmosis.

I had a Tornado cat which used to sit in moulded transom cups in the dinghy park. These were lined with carpet and she got blistered gel coat... in the area of the cups only... QED

 

[Clyde_Wanderer]

Thanks all for your replies/advice which was abundant.
I have some 1/4" thich rubber mat which is used under vibrating plates so as not to damage monoblock paviers when vib..g
Maybe try some of this as I wouldent imagine it would hold much moist.
Thanks.
C_W

 

[Porthandbuoy]

I've used pieces of old wetsuits over ply. Closed cell foam and nice and soft.

 

[Hoolie]

I've used pieces of old wetsuits over ply. Closed cell foam and nice and soft.

... or cut up a budget mouse mat, often made from the same material.

 

[nigelmercier]

Definatly NOT anything that holds moisture that is sponge like carpet/open cell foam etc, If you leave it for too long it can cause osmosis in the spots on the hull

I quite agree, it is very important that the hull on a boat is kept dry.

 

[rhumlady]

How about a rubber backed carpet tile rubber side up?

 

[Spyro]

I quite agree, it is very important that the hull on a boat is kept dry.

Did you miss one of these?

 

[Greenheart]

Sorry to wake up a thread after 18 months, but everyone who contributed here seems to know what I need to.

I'm fitting big rectangular 12mm ply pads to my trolley to spread the Osprey's weight better than the 3 inch thick bar on which she's spent the last 12 months.

I don't feel 100% clear about which surfaces will trap water next to the hull, and which can be relied upon to 'wick' moisture away.

The types of flat-bladed Astroturf I've seen, look as if they'd be squashed flat by the boat's weight, trapping rather than wicking-away moisture.

Likewise the closed-cell foam matting I've encountered in the past, securely traps wetness between itself and any neighbouring form.

The fabric (of whatever type) will go in the sea each time I launch and land, so it needs to be something that will shed moisture.

Any dead-certain solutions? I already have small blisters on the hull...don't want any more. Thanks!

 

[johnphilip]

Osmatic carpet

Can you give a citation (evidence) for this please ? I have never seen square patches of osmosis.

I agree with the dangers of carpet etc. Some years ago I had an RS dinghy and the trolley chocks were carpet covered. After a winter on the trolley there were blisters very evident on those areas. I replaced it with cut up rubber mat, the doormats with rubber "bristles". Great for dinghy as it allowed airspace but not heavy enough for yachts.
http://www.freundcontainer.com/bristle-brush-rubber-entrance-mats/p/v1122M23/
Such as these. I must admit I have not seen the like recently here.
Or more like these I have now found
http://www.nbbmatting.co.uk/14077_-Exterior-Matting/Rubber-Bristle-Mats.html

 

[jwilson]

Can you give a citation (evidence) for this please ? I have never seen square patches of osmosis.

Citation, no, but I have seen patches of blisters where wet carpet pads have been repeatedly. This is fairly common on dinghies and keelboats that spend 99% of their time ashore on trailers or launching trollies, and very little time actually in the sea.

 

[Daydream believer]

Is this a possibility?
Buy a sheet of Correx from Travis Perkins- about a fiver for 4ft * 8ft
It is basically a plastic version of cardboard used for protecting floors
Cut a couple of squares for each pad. It will crush to virtually nothing but will not attract damp

 

[rob2]

I replaced it with cut up rubber mat, the doormats with rubber "bristles". Great for dinghy as it allowed airspace but not heavy enough for yachts.

Not so sure about this for cradle pads as they are not carrying any weight. The weight is taken on the keel and the pads are to stop her toppling, so you may well find it still effective - but we'll only know for sure if someone tries it.

Rob.

 

[steve350]

Sorry to wake up a thread after 18 months, but everyone who contributed here seems to know what I need to.

I'm fitting big rectangular 12mm ply pads to my trolley to spread the Osprey's weight better than the 3 inch thick bar on which she's spent the last 12 months.

I don't feel 100% clear about which surfaces will trap water next to the hull, and which can be relied upon to 'wick' moisture away.

The types of flat-bladed Astroturf I've seen, look as if they'd be squashed flat by the boat's weight, trapping rather than wicking-away moisture.

Likewise the closed-cell foam matting I've encountered in the past, securely traps wetness between itself and any neighbouring form.

The fabric (of whatever type) will go in the sea each time I launch and land, so it needs to be something that will shed moisture.

Any dead-certain solutions? I already have small blisters on the hull...don't want any more. Thanks!

I use solid neoprene rubber on my cradle pads. http://www.ebay.co.uk/itm/Neoprene-Rubber-Sheet-Solid-Black-Smooth-1mm-1-5mm-2mm-3mm-4mm-5mm-6mm-/261237258709?pt=LH_DefaultDomain_3&var=&hash=item3cd2f439d5

 

[ianat182]

Dan,
You could fix some short lengths of 1 1\2" dia neoprene tubing mounted fore and aft on each of the trolley/trailer pads.When launching and retrieving your boat they will help slide the hull when wet.They will self drain and recover their shape after launching. Drill 1\4" dia holes on the upper and 1\8" through the lower surfaces of the tube to fix to the wooden pads.



ianat182

 

[johnphilip]

Not so sure about this for cradle pads as they are not carrying any weight. The weight is taken on the keel and the pads are to stop her toppling, so you may well find it still effective - but we'll only know for sure if someone tries it.

Rob.

As I said I did try it and it worked, even though in my case the mats took almost the whole weight of the boat as they covered a fibreglass beam that was shaped to fit across under the centre of the boat.
It looks as though the trailer is now supplied with rubber not carpet.
http://www.ldcsailing.com/rs400-twi...cName=parts-for-your-rs-rs400-covers-trailers

 

[Greenheart]

These suggestions are all very welcome. Let me say, I'm not worried about the softness of the surface the boat will sit on; the plywood sheets are smooth and flat and will be cut to fit between the strakes (if that's the term) so the boat's weight will have more support than just the trolley's narrow athwartship cross-bar. Forgive the filthy state of my hull:

View attachment 42419

So, my only concern is avoiding a damp patch lingering between the boat and the ply panels. Anything at all that separates them and disperses moisture (and encourages ventilation of the damp bits) has done the job. This firm rubber-bristle mat looks perfect...

View attachment 42420

...unless anyone thinks otherwise? Thanks to all.

 

[dgadee]

Can you give a citation (evidence) for this please ? I have never seen square patches of osmosis.

I have. Though boat must have been sitting there for several years.