Cradle puzzle

[kalanka]

I have a Tennamast cradle built c. 1995 for a Sadler 34 with wing keel.
This has not been used for a long time. Its basis is a rectangular frame of four longish scaffold poles plus a shorter one running to the bow support . Two of the long poles are 306 cm in length, two are 321 cm. The beam of the boat is 3.28 m.

I cannot remember which pair of poles run bow to stern and which run transversely.
I need to assemble the cradle for lift out in a new yard. Can anyone suggest which pair goes where?

This photo is of the boat and cradle 10 years ago.

Thanks

 

[rogerthebodger]

Only guessing but I would think that the shorter ones would be each side at the stern and the long would be towards the bow

But if you lower the boat onto the cradle and it looks you have got then the wrong way round just swing the boat 180 degrees

On my boat the aft supports are shorter that the forward supports.

The important is to ensure the main weight id taken by the keel on the base/ground

 

[LittleSister]

The important is to ensure the main weight id taken by the keel on the base/ground

. . . and that the poles are being compressed along their length, not pushed sideways.

Some people have them too high, presumably mistakenly thinking that the higher up the more support it gives. (It could, but only if the base of the cradle were unfeasibly wide and the poles much, much longer.) The posts are incredibly strong in compression, but will bend relatively easily if one end is pushed sideways while the other end is held in position by the base.

Imagine the boat falling over on its side (but the base of the keel staying on the centreline where it is). The pads need to be on the hull about where it would touch the base of that particular pole.

The company that made Tennamast are still in existence (or at least were a while back), even though they no longer make them. A rummage on the internet may find them, and they may be able to advise on the length issue.

 

[bedouin]

I would say the longer poles go bow-stern and the shorter across - but they are so similar in length that it really won't make a great deal of difference.

Can you work it out by looking at any marks made by the bolts (or whatever) hold it together>

 

[rogerthebodger]

This is how my 20 tone boat was supported in Durban

https://flic.kr/p/VKo5J6

Supported on a truck while od 1400 km road trip

https://flic.kr/p/WHUCJm

Supports while fitting out

https://flic.kr/p/WonQGJ

 

[James_Calvert]

My cradle for a Sadler 32 has a square base, 3m by 3m.

Max beam is 3.20m

The shorter ones should be fine run transversely.

Also check how the yard's boat handling equipment will get the boat into the cradle. A crane is no problem but a transporter might have some limits on the width it can straddle the cradle base.

 

[MontyMariner]

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