My bimbling continues with Ministry of Pleasure.... when I bought it from Richard C he mentioned that he had put an older mast back on her before selling it to me and that problems I was having getting the jib 'hook' attached might be because of the mast .... everything seemed too tight...which leads me on to my real question
The one string system is still causing me problems.... am I correct in thinking that the block (under the mast) on which the lowers, shrouds and jib hook halyard are attached to, works by either taking pressure off the jib halyard and increasing pull on the lowers and shrouds (raking) ... and vice versa (straightening)? The other issue that I'm having is that the lines that lead back port and starboard to the one string seem to be different lengths and in my case the port 'string' is really tight and the starboard 'string' has too much play in it. Adding all this together pulling either of the strings doesn't really do anything as there doesn't seem to be enough play in the system (I can probably move the block about an inch up or down by pulling the control lines). Any advice would be appreciated. 

 Hi Rousey,
 
The one-string system is something that I am very familiar with, having retrofitted it to 3615.  Your one-string line  length issue is down to it having been uncleated on one side when pulled on the other, as it is a continuous line through both sides and needs to be fully cleated on one side for it to work, so uncleat the starboard side and pull on the port side to equalise the line lengths before recleating all of the lines.
 
In terms of the one-string block you are correct in the way that it works.  The Shroud tension tightens up the whole system, so if that is fully let off you should then be able to unhook the jib easily, if not then you may need to lengthen the jib halyard.  The jib halyard is what is in control of the rake, so you will need to ensure that it is the right length to set your fully upright position and then adjust everything from there.  Another consideration as it is a different mast is that the shrouds are probably a different length to the mast that was used to set the boat up with, so you may need to lengthen the shroud purchase.  The start point for me would be to get the Jib Halyard sorted, a shackle on the top of the jib may be all that is required, to get the mast upright position set and then work from that.

Thanks Stuart.... I'll give that a go! If that works then if I pull one line the jib halyard relaxes (i.e. the central block moves up) and the mast starts to rake, and if I pull the other the jib halyard tightens (central block moves down) and the mast straightens?
 
many thanks
Martin 

.... and not forgetting the effect on shrouds and lowers!!!

SB’s tips are really good. 
The strop between the head of the jib, and the 2:1 on the mast can vary, as can the length of the forestay inside the jib too.