Floor and frame spacing

[BANYAN]

Hi all.  I am in the midst of redrawing the plans for HMCSS Victoria (steam screw sloop) and wishing to add some additional details.  Unfortunately, due to copyright issues, I cannot post the plan here.

 

Please Note:  These questions relate to ship building practices of the mid-19th century.

 

The Specification for her build required floor (centres) to be spaced 2, 3 and 4 feet apart as shown on the 'section' drawing.  Unfortunately this drawing/plan has been lost and they are not shown on the profile/sheer plan.  Additionally, the bent timbers (in lieu of frames) were to be placed midway between the floors, and the spaces filled in solid.  The floors only extended to the 'round' (or the head of the first buttock) due to the unusual way this vessel was built.

 

The final bit of info I have found was a small tid-bit in the record of proceedings of a Court of Inquiry in which the Inspecting Officer (naval architect) in one of his responses stated the floors in the after part were about 2 feet apart.

 

My questions:

   1.  What would be the likely spacing in various parts of the vessel?  I have assumed that perhaps the keel between the rudder post forward to the forward bulkhead of the machinery space (combined stoke-hole & engine room) would have had 2 foot spacing, then forward of that to perhaps just forward of the pivot gun having 3 foot spacing and  4 feet ahead of that (to the start of the cant/half frames which was the most forward station shown on the existing plan)? 

 

  2.  The floors were sided 12" and the bent timbers 8".  The meat of the timbers would thus occupy 20" of the 24" spacing.  This means the filler in these sections would be sided just 2" (x 12" moulded/deep).  Is this viable/feasible do you think?

 

Any comments or suggestions about this would  be most gratefully received.

 

cheers

 

Pat

 

[BANYAN]

Bump!  Any clues anyone?

 

cheers

 

Pat

[wefalck]

My sound like a stupid question, but have you consulted any shipbuilding textbooks of that time? There is a variety of English language mid-19th century texbooks available on the Web.

[BANYAN]

Thanks for responding Eberhard.  Yes I have consulted several contemporary authors including Fincham, Peake and Scott-Russell.  All speak in general terms and there are very few diagrams/illustrations showing framing of this time.  Where there is framing discussion, unfortunately it is for standard construction and not that using bent timbers in lieu of frames and no one speaks of differing frame spacing. That is  2, 3 and 4ft spacing in the same vessel - these authors tend to suggest a regular spacing, which in this time is said to be between 2'7" and 3' 6", one set of spacings throughout.  My question is really in terms of general convention and probably only able to be answered in subjective terms - that is, where do people think the more dense/closer (i.e 2ft) spacing is most applicable?

 

Thanks again

 

Pat

[wefalck]

I gather areas, were the load would be high, e.g. from the pivoting and firing guns, could have closer spaced frames, dito., where boilers and machinery are located. In the bow, the cant-frames are spaced closer to better take up the stresses from diving into the sea.

 

On the other hand, uneven frame spacing would also cause uneven stress distribution along the hull, with some areas being stiffer than others. This should lead to higher stress on wales, stringers and the hull-planking in these areas. By then the spacing is already quite close, so that there may not be a quantitatively significant effect.

 

When you say 'bent' frames, you mean they really steam-bent such big timbers, as you would in boat-building?

 

[BANYAN]

Thanks Eberhard, appreciated the continued feedback.  I agree, closer where load and stress would be greatest but agree, differing spacing is difficult to accept.  However, it seems this was implements as it was specified in the build Specifications and drawn in Lang's plans.  

Also, yep as best as I can tell they were steamed into pretty sharp 'U' bends.  These timbers replaced the shadow moulds used to form the diagonal planking and were smaller in dimension than regular frames would have been. Several authors writing about wood ship construction in the latter half of the 19thC mention bent timbers and their writing supports/infers bent rather than jointed timbers.

The hull construction was very different hence all this confusion, as there is not much in the way of reference materials to provide guidance too many assumptions having to be made by myself for my liking at the moment.

 

cheers

 

Pat

[BANYAN]

On 9/2/2024 at 5:26 PM, wefalck said:

When you say 'bent' frames, you mean they really steam-bent such big timbers, as you would in boat-building?

Hi Eberhard, sorry missed you question on the first read.  Short answer "I don't really know"

From everything I have read so far, the bent timbers were put in after the diagonal planking had been completed.  Shadow moulds (as they are called in the related correspondence from the build superintendent) were used as temporary framing/shaping members.  These were taken out and replaced with bent timbers and iron knees/plates (alternating bent timber/plate to beam, bent timber.  The floors only extended to the round of the hull (first futtock), and the iron plates extended down to these picking up the top of the floor timber with a single bolt.  Everything I have found to date suggests they were a single bent timber that went from gunwale to gunwale, and that were indeed steam bent.  However, their scantling was not as heavily a timber as a frame.

 

If you ever come across anything else it will be most gratefully accepted.

 

cheers

 

Pat