Retrofitting Bronze Strapping

[TimothyB]

Has anyone had occasion to fit out an older wooden boat with bronze (or even steel) diagonal strapping in order to stiffen up the hull?

Anyone have any thoughts on this? I've read Dave Gerr's Boat Strength book and he has a great section on using it for carvel planked boats to prevent wracking, and of course Old Ironsides has diagonal strapping too, though of Oak. smile.gif

[Bob Cleek]

Hard to imagine anybody doing that. The strapping is only worth the trouble on larger boats that might be prone to hogging over time. In order to install it, you'd have to completely remove all the planking and decking, down to the frames. Not a pretty thought!

[Wiley Baggins]

Originally posted by Bob Cleek:
...you'd have to completely remove all the planking and decking, down to the frames. Not a pretty thought!Refitting an older boat seems prohibitive unless one has more money than sense ( or the deity of your choice). Maybe composite strapping on a cold molded hull, but the work involved in traditional strapping as a retrofit is daunting absent the "need" to restore a "classic" where the value of the boat itself is outrageous.

//begin hijack

Originally posted by Bob Cleek:

Next thing you know we'll be seeing crop circles on this forum! ;)

//end hijack

[TimothyB]

Ha! Knew that would get a surprised and 'why would you do that?' response. smile.gif

Its just a noodler I had in my head actually, not planning on doing it anytime soon. Nor on the boat we are currently looking at, but the question has popped in my head a few times, and here is my basic idea.. somebody stop me if I am absolutely insane:

1) Assuming we have a carvel planked boat
2) Assuming that boat has substantive frames
3) Assuming the frames are not in need of repair any time soon

The basic idea was to cobble strap rather than run the strapping all the way (which would, I agree, be insane). You would use thick bent brackets, thru bolted to each frame (one on each side) that would be attached to a strap running from frame to frame, and the strap would, of course, be screwed to the planking.

If the brackets were sufficiently strong, it should have a similar effect to running strapping through and through.

Now I know folks are itching to say 'why do this?'. Well, who knows? Im more curious about the possibility than the actuality. ;) I just like throwing stuff against the wall. Its the scientist in me I suppose!

[ 08-25-2004, 11:19 AM: Message edited by: TimothyB ]

[Andrew Craig-Bennett]

Bob Cleek, him right.

Tim - the strapping works in pure tension. Your brackets would flex too much for the strapping to make any difference.

[TimothyB]

Hmm.. good point Andrew. Well, you could always put them on the outside and double plank ;)

--T

[Andrew Craig-Bennett]

No joking!

It was standard practice to "double" Thames Barges when they reached a certain age, and the same has been done to other boats; two that I know of, the Faversham bawley "Good Intent" and the yacht "Alan III" were both doubled carvel over clinker at some point in their lives.

[TimothyB]

Well, as Mr. Cleek might say:

"There ain't nuthin new in the world"

:)

Fascinating!

--T

[ 08-26-2004, 11:56 PM: Message edited by: TimothyB ]

[Andrew Craig-Bennett]

Thinking about it, the oldest boat I know still in regular use, the 30ft Colchester smack "Boadicea", CK 213, built in Maldon in 1808 (that is not a misprint!) is on her third set of planking!

Built clinker, doubled carvel around 1870, replanked (carvel, teak) by Michael Frost in the 1970's. She is quite a special boat; like the Victory and the Constitution, she survives from before the War of 1812, but unlike those two, she goes to sea most weekends!