David is quite right, but of course it might have been made for a gaffer. In which case, however, you would want to take a lot off the upper section to taper it.

Yes, it would probably be heavy, but Arne has successfully used wooden spars on earlier boats. He also has a very good article in his stuff all about the wooden mast, which you might find useful. Highly recommended.

While you re planning to sail around NZ, you're not planning to cross the Southern Ocean, so the mast needs to be strong, but not perhaps ultimate strength. Both Arne and Pete Hill reckon that PJR masts are about 10% more massive than necessary ...

My calculations using the PJR formula for a LAP of 8 and a SA of 37 indicate that a 20.5 cm diameter mast (23 minus 10% because it is solid) is sufficient. The mast in question is 19cm. 

I intend on sailing round NZ in this boat, so heavy weather is expected. How important is that 1.5cm diameter...

I am thinking that it would probably be pretty important but thought people with more experience than I could be more definitive. 

The reason I ask is that it is a ready made, two pot painted mast, plug and play basically.

I know of at least one New Zealand standard H28 which has circumnavigated the globe, and I know of another H28 glass hull with a timber deck and cabin which has spent more than the last decade cruising the Pacific. I expect there will others which have made offshore voyages, so they are capable vessels.

I very much doubt that there was ever a boat launched that displaced the same (let alone less!) as the designer had intended/hoped.  Certainly, Fantail was closer to 3 than the 2.5 tons she was designed to be, and the marks for her designed waterline were at least 100mm below the one she had been floating on for years (judging by the many coats of antifouling that covered it.  And apart from the time that I owned her, she has spent her life as a weekend/holiday boat with pretty minimal gear on board.

You can soon fit a ton of gear on board: anchor tackle (three anchors, 30 fathoms/50m of chain between them and then around 150m warp), mooring lines, spare rope, spare sails (if you have that sort of rig), 25 litres fuel for the engine, ditto for the cooker, 80 litres water, tins and containers of food, bosuns stores, tools: and judging from most boats, the owners regard an empty locker as a challenge that must be filled.  I think you are wise to assume the boat was at least 3.5 tons when launched and probably nudging 5 tons by the time you are kitted out for Milford.  When boats are launched their tanks are empty, they have a dinky piece of jewellery on the bow that is supposed to nail you to the bottom in F8 and even fenders are on the 'extra' list.  Thus and therefore, one has to assume that all the above come under 'personal stuff'.

The Pelorus is significantly smaller and would obviously displace a bit less than an 'H28'.  (For non Kiwis, the boat that Daniel is talking about is considerably altered from the original and quite apart from being built of 'frozen snot' would be almost unrecognisable to LFH.)  The Pelorus's original rig was definitely that of a motor sailer, however, which is the main reason for the difference in sail area.

I see that you certainly do have a self-destruct valve, Daniel.  I trust you are going to get rid of that terrifying and undoubtedly de-zincifying gate valve asap!  The first job I did on Fantail was to put her on a grid and get rid of the ones that she had been fitted with.  They gave me nightmares.

Interesting. According to the original Half Moon Bay Brokerage (1975 Compass Yachts) brochure (found on the H28 Owners Assn. website) the displacement is 7,400 lb - hard to believe, I would have thought it a bit more than that.

And the ballast is given as 4000 lb (a surprisingly high ballast ratio) though elsewhere it is also given as 3,500 lb. with reference to further trim ballast. Some of these had lead ballast and some had steel punchings in resin, I believe, so there is room for a little variation (and skepticism.)

Anyway, if the displacement really is only 7,400 lb, that's 3,360 kg which is very little more than what I estimate my Pelorus to be.

I would expect the H28 to be a bit stiffer than the Pelorus though, and one thing is for sure, the working sail area (quoted as 359 sq ft) is considerably more than Pelorus (estimated to be 286 sq ft) so Annie is right, its a "bigger boat" and I guess you will want to accept the advice from David. If you choose one of the stock Ullrich sections I will be interested to see which one you choose.

(1,000 kg for "all my stuff" sounds a bit high! I would have trouble finding enough storage space for a tonne of personal stuff. My heaviest stuff is books and I have had to leave most of them ashore.)