Deck clamp notches

[Dziadeczek]

I have a question. How do you cut these notches for deck beams into the deck clamps? I understand that doing it off the model would be much easier, but then, how do you determine their exact locations OFF the model?

On the other hand, cutting them on the model would be exceedingly difficult due to immediate proximity of frames and external planking (not enough space to manouver cutting tools).

Any help would be appreciated.

Regards,

Thomas

 

[mtaylor]

Thomas,

 

Try fitting the clamp to the hull then drill several holes (exact size of the pin) and pin them to the hull.  Removing the clamp and re-pinning should return the clamp to the exact spot.  You can then mark the slots and pare them and return the clamp to the exact location.  I think Danny V. and EdT use this method.  I'll be giving it a shot when I get to that point.

[Dziadeczek]

Good idea! I will try it.

Thanks!!!  

[wq3296]

Greetings Dzia...

 

It is my understanding that the deck beams sat on top of the deck clamps. The beam ends were notched to fit over the clamps such that the beams could be adjusted to the the right height to accommodate the deck planking. This method would insure that the deck would be set at the proper elevation which was not necessarily related to the clamp height. Note that an important function of the deck clamp was to tie the frames together. If the clamps were to be notched as you show, it seems that they would be considerably weakened, defeating their purpose.

 

NOTE: this is my opinion and I am open to information that would show otherwise.

 

wq3296 

[druxey]

With all due respect, wq3296, the scores (not notches!) are maybe an inch or so deep, so would not really compromise strength. Besides, once the hanging and lodging knees are installed, the entire structure is considerably reinforced.

[wq3296]

Greetings Drux...

 

Seems reasonable. You are saying that the beams were simply let in to the clamps and not fully mortised in as the photo appears to indicate. This approach could reduce the need to notch the deck beams. I agree, too, about the lodging/hanging knees providing strength at the deck beam connections. 

 

wq3296

[druxey]

The photo shows the French method of attaching beams using a dovetail. The English method had a shallower score and no dovetail.

[Dziadeczek]

You are right about that, Druxey. This indeed is a French 74 gun ship model. J. Boudriot in his "The 74 gun ship" vol. 1 writes:

 

[SJSoane]

 

My own experience with the Bellona is that the clamps are so fiddly to install, they would not easily have been removed to notch and then reinstall. They change their lengths slightly as they are conformed to the hull sides (particularly the upper deck clamps on a British 74), and any notching when they are not fully bedded down would result in inaccuracies fore and aft.

 

So I opted for installing the clamps first, focusing on keeping their tops at the precise line marked on the bulwarks (deck height at bottom of planking minus thickness of beam, plus 1" as Druxey notes). Fully glued and pinned in, they form a solid foundation for everything else to follow. I then located each beam very accurately in its fore and aft location, temporarily clamping it in place with a small C-clamp. I then marked each side of the beam on the top of the deck clamp with a very sharp knife, and scribed down from this line 1" in scale from the top to mark the sides of the mortise. I used a small jig to scribe a line 1" down and parallel to the top of the clamp, to locate the bottom of the mortise.

 

With the mortise accurately marked out on top, side and bottom, I then used a variety of small chisels and hobby knifes/scalpels to cut each mortise. One inch down at 3/16" scale is easily done by this method. Following full size practice, firmly press down vertically with a knife on each scribed line on the top, then take a slice from the top center of the mortise to each side you just cut, forming an inverted V. Cut from the middle so you are always cutting down on the grain into the stopping cut, thereby avoiding unexpected splits. Cutting this way also means that a knife can be brought to bear from the side, rather than the top where the tumblehome can get in the way.

 

Do the vertical cut and then V cut on each side several times until you cut down to the 1" line. Then pare off the remaining inverted V with shallow horizontal cuts until the V is gone and the mortise is 1" deep. Easier to do than to explain. One key is to take a number of very shallow cuts, so the wood is easily pared, rather than forcing deeper cuts. The other key is to scribe the lines marking the mortises, from the beams themselves and from a jig for the bottom. The scribed lines give a very accurate register for the chisels/knives that you can feel in cramped quarters even when you cannot see the line. 

 

Even if you cut the mortises first, you will likely still have to make some adjustments to them once installed, to ensure that the beams are all exactly at the height of the deck minus the decking. I used long templates to sit on beams at the middle and at both ends of the deck, so all intermediate beams could be brought level to the template. So if you are going to adjust the mortises slightly in place anyway, why not cut them in place to start?

 

Once cut this way, the mortises provide very precise beds for the beams fore and aft, and vertically. I drilled through the tops of the beams into the clamp where possible, more often into the bulwarks, for pins. I cannot begin to count the number of times I had to locate and remove the beams for further work, like marking and cutting the mortises in the beams themselves for the carlings. The precisely located mortises were my friend.

 

For those who are anxious about hand cutting mortises, I took inspiration myself from Gaetan Bordeleau, who pointed out to me that the more you cut by hand, the more comfortable you become with cutting by hand. It was like training on the job. And if you follow the advice of shallow paring cuts into stop cuts, you can't go drastically wrong in any given slip of the knife.

 

Mark