My tubes were exactly the same, it doesnt take long for water to get in and start to lift the cone seam. To do the job properly the strakes need pulling back and cleaning off, and the seam patches need the same treatment and re gluing, then the strakes can be re glued, then a big patch over the lot to keep the water out. The leading edges of which need to be sixaflexed to stop the edge lifting. i did mine myself and it took a good day to do the one side, and a half day to just put the overpatch on the otherside to match. (£100 parts of Mr Tilley)Its not a pleasant job unless you like getting covered in glue, sikaflex and intoxicated with toluene fumes. Its a one hit job too, once the hypalon toyches the glue it wont beel back again if you get a crease. Paul Tilley and Henshaws make it look as easy as falling off a kerb!
I suggest you reas NOS article on buying a used rib and take note of the comments on wooden boats like seariders, decide for yourself what you are willing to pay for it. If the engine is good, trailer is good, (apart from possibly being illegal because of no brakes and a plated weight over 750kgs) and the boat core is dry, then as wa both previously mentioned its worth in the reigon of £2750. Knowing the work thats involved tidying SRs up i would want to pay around £2250 so i could get it all sorted and tidy for less then £4K If you can get it for between those two figures then you will have a reasonable deal. I think £3k would be absolutley about it, if the engine had the decals on, the tubes were glued back, and brakes fitted, it would be worth more, certainly at peak season, however the price of everything seems to be dropping at the moment and there have been some real bargains on fleabay, try a cheeky offer and point out all the faults(quite often i find sellers are ignorant of the fact there is a problem and will negociate when you point it out) they can only say FO.
A bit of a ramble hope it helps