Get the mast height, multiply by 2.5 (if going back to cockpit) multiply by number of halyards. Go to Jimmy Green website, select size and type of rope, multiply by length from sum above and then by price per metre. Add splices and eyes as appropriate.
Have a large scotch and then start to negoitiate discount.
Who sez? A surveyor?
Your insurers may insist on standing rigging being done every ten years, but after owning eight secondhand yachts I have never had to replace all the running rigging at once.
Much can turned end-for-end to extend life, but more important is using the boat and improving when you replace.
But do it piecemeal I beg you!
I was looking around the boatyard this morning, after last night's 60 knots recorded at Beaumaris. Several halyards shredded, several more blowing around. Every boat on the hard, maybe 100? appeared to have its normal sailing halyards in place. Are these people all millionaires?
Years ago I bought a reel of 6 mm polypropylene which I cut to length for winter halyards. Last job of the season is to pull out all halyards with the polyprop winter replacement attached with a short length of stainless wire. The whole job takes about an hour. I can then wash the halyards and stow them safely over the winter. Consequently, a requirement for new halyards is a rare event for me - I have replaced two this year, one was 12 years old and the other at least 15. All the others are at least 10 years old and still in good condition.
I, likewise, doubt if you 'need' to replace it all at once. The surveyor is covering his/her arse by pointing out that some of the rope is past its best. I bought my current boat 2seasons ago and have replaced some running rigging but not all. I keep thinking about replacing the mainsheet because it's (a) thinner than the optimum and (b) much longer than it needs to be, but so far I haven't actually bothered.
You could easily spend £300 or so on new running rigging for a boat that size, using 'ordinary' rope. More if you have splices made professionally and much more if you decide to renew more than a couple of shackles as well. Much, much more if you use very expensive materials such as dyneema etc. If you are going to buy the boat thank your surveyor and use it as a price-negotiating point.
As others have said, unless a rope is obviously badly worn then the chances are you can get away with what is on the boat. On my boat when I bought it all the ropes looked dreadful; I just washed them all in the washing machine and then refitted them - a couple I reversed them and respliced eyes. That was 4 years ago and since then I've only replaced the mainsheet as it wasn't long enough. Don't forget that most rope is far stronger that it needs to be and often only the size it is for comfortable handling.
you are all rite it may not need replacing and the survey is yet to be completed but we are looking to go cruising on it so we will have it all replaced no matter what the condition. from us looking at we would say it is well used. but then like you all say, with a little wash up it could provide many more yrs service