Another Steel question

[Don Case]

I was getting the stern post dimensions from Steel and I couldn't find the length. It was very detailed about all other dimensions but no length. Would it be somewhere else? I can get the length from the plans I have but it just seems rather strange that I can't find it in Steel. I even measured it on the plans(it's 19') and looked for any 19' measurement in Steel and couldn't find one. I could find the wing transom height above the keel but it's down a bit from the top of the stern post.

[Mark P]

Good Evening Don;

 

In the ships of the Royal Navy, there is no set length as such for the stern post mentioned. It was made as long as possible in order to give the maximum support to the rudder, but in order to allow the tiller to enter the ship and swing to steer the ship, the sternpost had to stop short of the underside of the tiller. Its top coincided with the helm port transom, a specially shaped timber which had a downward cast in its centre, to allow the tiller to swing. The helm port transom could not be maintained in a straight line, or it would have meant that the tops of the stern chase ports would be too low. 

 

See attached an excerpt from the NMM's draught of the Dorsetshire's inboard works, which is one of the most beautifully detailed of its kind around. 

 

 

Next below is a picture of the stern of the framed model of the Bellona, also in the NMM. In between the gunports you  can see the downward cast section of the helm port transom, with the higher sections of it running thwartships on either side. Above the hole for the tiller, you can see the deck transom, which had to pass over the tiller. This set the maximum height for the tiller; as you will see from this, the positioning of the timbers in this area is inter-dependent. 

 

All the best,

 

Mark P