Safety of Shore/Props

[Scotty_Tradewind]

I've just seen the posting of the 'accident' where Clyde_Wanderers boat has been hit by another whilst ashore.
http://www.ybw.com/forums/showthread.php?t=296397

My own personal opinion is that the modern steel stand/props are not as reliable to stay gripped to the boats bottom as the traditional timber shores with a wedge.

I have seen many boats ashore temporarily sat with just 4 modern props holding them up, which makes me very anxious.
I have often found a modern prop will not hold well against the hull and has been found very loose.

The one prop that I notice commonly drops away is that which sits under the bow.

Although my yard regularly taps home the wedges as the boats 'settle', I still check tightness of things myself.

I would advise any boat to have at least two wooden shores with wedges either side and to be cross braced, even though steel stands may also be used.

Boats that tend to be bows heavy really do need that shore/prop under the bows at all times.

 

[Resolution]

It has always amazed me that there aren't more accidents in moving yachts up onto the hardstanding and propping them off. Just yesterday I was looking at a row of 40 to 50 footers, all on modern cradles in good condition, but with only 6 pads. The pressure on each pad in a crosswind (all masts were still up) must surely be considerable. But beyond my schoolboy mathematics.
Are modern cradles designed by engineers with marine experience? Perhaps one of them could come out of the woodwork and explain to us just what is involved?

 

[Scotty_Tradewind]

It has always amazed me that there aren't more accidents in moving yachts up onto the hardstanding and propping them off. Just yesterday I was looking at a row of 40 to 50 footers, all on modern cradles in good condition, but with only 6 pads. The pressure on each pad in a crosswind (all masts were still up) must surely be considerable. But beyond my schoolboy mathematics.
Are modern cradles designed by engineers with marine experience? Perhaps one of them could come out of the woodwork and explain to us just what is involved?

I reckon in extreme conditions I'd add to a cradle, a couple of cross-braced wooden shores/props with wedges.

 

[RupertW]

I've just seen the posting of the 'accident' where Clyde_Wanderers boat has been hit by another whilst ashore.
http://www.ybw.com/forums/showthread.php?t=296397

My own personal opinion is that the modern steel stand/props are not as reliable to stay gripped to the boats bottom as the traditional timber shores with a wedge.
.

In the winter 1989 storm which caused more boating damage than the better known 1987 one, there was a complete change of heart about wooden props and wedges as boatyard after boatyard looked like stacks of fallen yacht shaped dominos. Alas including my own boat.

Our boatyard guy and many others described the boats being lifted by the wind so all the props on one side simply fell away. The point of the modern frames is that in those circumstances the yacht would drop back into the frame.

However the biggest remaining difference to the 50s and 60s approach is that then yachts ashore were much more likely to have their wooden masts taken off and in a shed for the winter maintenance tasks. Also sails were prone to rot so wouldnt be left on booms and forestays so much less windage than most today. With no mast or sails and low profiles being the norm then the old style props stood a lot more of a chance.

 

[DJE]

Also sails ... left on booms and forestays...

The yard where I'm based won't haul the boat our unless the sails are removed.

 

[[2574]]

isn't the best plan to stay floating?

I much prefer my boat in the water during these gales. She's in a locked marina basin and therefore very secure. We come out for a fortnight only in the spring, this minimises exposure to shoreside risk. A boat is designed to float in an all supporting liquid not on four 300mm x 300mm pads and the keel.

 

[RupertW]

I much prefer my boat in the water during these gales. She's in a locked marina basin and therefore very secure. We come out for a fortnight only in the spring, this minimises exposure to shoreside risk. A boat is designed to float in an all supporting liquid not on four 300mm x 300mm pads and the keel.

Same here since 89. I also have kettle, loos, mains power, engine cooling water and and a bed available all year when doing winter maintenance. Just take it out briefly once every other year for anode and antifouling.

 

[Scotty_Tradewind]

In the winter 1989 storm which caused more boating damage than the better known 1987 one, there was a complete change of heart about wooden props and wedges as boatyard after boatyard looked like stacks of fallen yacht shaped dominos. Alas including my own boat.

Our boatyard guy and many others described the boats being lifted by the wind so all the props on one side simply fell away. The point of the modern frames is that in those circumstances the yacht would drop back into the frame.

I suspect in that extreme neither type of prop would have kept keep the boats up. Once a modern prop is loose it simply slides up the hull too.

Has anyone knowledge of how the boats in the recent Greek 'pack of cards' were propped/cradled?

I guess the strong cradle is the better answer?

 

[jerram]

For the last 10 years I have left the boat on her pontoon moorings, She comes out when the weather is fine for a polish, antifoul and anodes, Why miss the late sailing season and the quite Feb days out, I have seen to many boats go over with the domino effect in the boatyard never seen one fall over on her moorings yet!

 

[Boathook]

With a Cat I don't have to worry about props -except for those used by other boats. Mine is resting on some wooden blocks which are located under bulkheads as best as possible to spread the load. This does make it easier to do the antifoul. Taking masts off is a pain now days with so many bits of wire to 'remove' and then you have to protect all the bits attached to the mast such as radar.

 

[Poignard]

I

I guess the strong cradle is the better answer?

I think so. I had my cradle made by the now defunct Pepe Boatyard on Hayling Island, it is wider than the boat's beam so gives great stability. £550 well spent!

 

[Sandy]

I much prefer my boat in the water during these gales. She's in a locked marina basin and therefore very secure. We come out for a fortnight only in the spring, this minimises exposure to shoreside risk. A boat is designed to float in an all supporting liquid not on four 300mm x 300mm pads and the keel.

I like this post

 

[Poignard]

A boat is designed to float in an all supporting liquid not on four 300mm x 300mm pads and the keel.

When in her cradle my boat is standing on her keel. The pads just prevent her falling over, and are very lightly loaded.

Boats are, as you say, primarily "designed to float in an all supporting liquid" but they must still be capable of standing on their own keels without being strained or deformed. If not, how could they be built in the first place, or dry out alongside a wall?

 

[Ruffles]

I suspect that cradles are often not adjusted so that the pads align with a bulkhead. Combine that with fewer points of contact compared to traditional wooden props and there must be a possibility of punching a hole in the hull in extreme conditions.

 

[Tranona]

Boats are, as you say, primarily "designed to float in an all supporting liquid" but they must still be capable of standing on their own keels without being strained or deformed. If not, how could they be built in the first place, or dry out alongside a wall?

Whilst there are advantages in designing a boat so that the keel can take its weight, can't see how it affects it being built. Most boats now do not rely on the keel for strength of the hull and are built completely before the keel is added. Being able to dry out alongside a wall is only of value if you keep your boat in an area where the tidal range allows this. Of little value to the thousands of boats kept in the Med where there is virtually no tidal range.

 

[Judders]

I've been out of maine insurance for nearly four years now, but my view then is as it is now that well placed wooden shores are actually better than cradles. Firstly, they can all be placed to suit the particular boat and secondly the boat is supported in as may places as needs be rather than four.

Sadly, the downside, as we see in the other thread, is that it is a lot more likely that old fashioned shoring will be ballsed up than the use of modern cradles. Furthermore, is a boat is shifted in its cradle, it will most likely only damage itself.

 

[Bosun Higgs]

Its a condition of my insurance that the boat when ashore is in a purpose made professional cradle.

 

[sarabande]

Atlas steel cradle for rent over the winter period.

Suitable for 30 - 40ft boat. Six legs. Storm chains. As here:-

http://www.atlasyachtcradles.co.uk/pages/ac-yacht-cradles.php

Can deliver - based nearish Exeter.



pprtunistgrinicon:

 

[Rum_Pirate]

Hmm, this was discussed before on this very forum in July/August 2005

http://www.ybw.com/forums/archive/index.php/t-66226.html

 

[dunedin]

When in her cradle my boat is standing on her keel. The pads just prevent her falling over, and are very lightly loaded.

I assume therefore that your mast is down. With 60+ knots of wind on the side of the hull, and the leverage of a rig which is probably vibrating heavily, I would expect that that the shock loading on side legs and pads is a very long way past "very lightly loaded"