What are these?

[michaelpsutton2]

This is the main channels of the Andromache of 1781. There are several eyebolts in the hull below the chanel between the chain plates (red arrows) and to rather sturdy looking solid plates not associate with a deadeye (green arrows).  The fore chanel is similar. Anybody out  there who can teach me about these?

[Mark P]

Good Morning Michael;

 

These are for use in emergencies, when the chain plates or channels have been carried away by battle or storm damage, and were to enable the attachment of jury rigging for the shrouds.

 

All the best,

 

Mark P

[Thanasis]

Hi.

According to my library, Those blind chain plates, seem like  additional suport (beneath) for the channels themself. 

The eyebolts could be fitted for general use...(?).

Thx

 

Edited October 8, 2022 by Thanasis

[Bob Cleek]

I believe the "solid bars" (green arrows) are supporting struts for the channels. The chainplates carry the upward strains of the shrouds transferred to the hull, while the channel struts bear downward strains on the channels. Some channels on larger vessels were quite wide and the compression of the chainplates and shrouds was not sufficient to support the channels which ofter served as platforms that had to carry the weight of crew standing upon them to perform various tasks such as casting and recovering the lead line when taking soundings.

[Mark P]

Good Evening Michael;

 

My previous answer referred only to the eye-bolts; the plates serve a different function. Without denying their support function, and without being certain of what I am about to say, it is likely that these solid plates were made with an eye in their upper end, to which the lower block of the tackle which ended the shifting backstays could be hooked. These backstays were rigged as additional support for the upper masts when under sail, and would be shifted as the yards were braced further away from the central position. They would only be hauled taut/rigged on the windward side of the mast at any one time. 

 

All the best,

 

Mark P

[BANYAN]

Oliver Lang (senior) developed a new way of putting on chain plates.  See "Extracts from ‘Improvements in Naval Architecture Improvements’ by Oliver Lang (1848) – British Museum 1397 e18"; specifically 

 

VI (page5)

Preventer eye bolts for shrouds.  Removed them from the strake in line with the chain bolts, which, as formerly fitted, destroyed the strake and timbers of the frame in that range, by cutting them to pieces, and wet coming into this part of the ship decayed the timbers; and, when under repair, I have seen the said timbers drop asunder, being cut off with holes and rotten.  By removing those large eye bolts to the next strake above, it not only relieves the strain from that part, but preserves the strength of the timbers and prevents decay.  This improved mode was adopted first in the Hind, 1805, afterwards in the Leonidas, 1807, Clarence, 1811, and has since become general.

 

The eyes Michael asks about may simply have been (as suggested by MarkP),  eyebolts for the preventer backstays prior to Lang shifting them to a separate strake as shown in the German illustration provided by Thanasis.

 

cheers

 

Pat

[Thanasis]

Hi again.

This is what I found in another book...

 

Edited October 9, 2022 by Thanasis

[michaelpsutton2]

Thanks all. I think I undersatnd now. Most plans are not detailed enough to show those. So I have seldom encountered them.

 

[Beef Wellington]

7 hours ago, michaelpsutton2 said:

Thanks all. I think I undersatnd now. Most plans are not detailed enough to show those. So I have seldom encountered them.

 

Like many things, I believe it depends on the period and the nation in question.  From what I understand, the iron T-plates gradually replaced the wooden knees as metalwork became more prevalent in late 18th century.  Thanasis' post above shows the redundancy that seems to be in place by having both - which probably did occur during the transition, and seems to have been ubiquitous through the history of ships.

[dafi]

The Tee-Plates also can be seen on todays Vic. The eyebolts were for emergency as already said, but also to put pulleys for the deadeye lanyards, to straighten the shrouds to ease the lanyards and of course for any other purpose possible :-)

 

XXXDAn