altering a box spar to fit another boat

[imported_Jimmy]

I have found a used box spar that is almost the same size as the rotten one I want to replace. It is only a foot longer and 3/4" wider in each direction, but it won't fit through the hole in the deck. It is even more than 3/4" in one direction since the old mast is 1" narrower on the aft side. If I want to use this mast I think I can do one of 2 things, make the mast smaller or cut the hole bigger. Which is best?

Cutting the hole bigger seems like the easiest solution, but it looks like the previous box spar had been cut or built smaller at the bottom so I was wondering if this is a better solution. The old box spar is 6.25" x 4.25" without taper, but only 5.25" x 4.25" for the bottom 8 feet while the new one is 5" x 7" without any taper all the way to the base.

Thanks.

[mmd]

Don't mess with the stick. If you can alter the deck blocking and maststep without disturbing the frames or deckbeams, that would be the way to go. If surgery of the boat structure or the mast is needed, you are better off selling the newly-acquired mast for enough money to buy the raw materials to build a new mast that fits.

[imported_Jimmy]

I will take a look at the frames and deckbeams to see if I can fit the new stick through the deck without major changes. If I can't though, I plan to trim down the used mast.

How much room should there be at the partners? I assume it can't be too tight or you wouldn't be able to get the mast in. The openning on my boat is almost 5" x 6" so I wouldn't have to enlarge the hole or trim the mast very much if it can be fairly snug. (I've never seen the mast on my boat it came stored separately).

[mmd]

Usually the mast has enough clearance thru the deck & partners to allow wooden wedges to be driven in firmly to align the mast to it's desired rake and hold it in position. I don't know the details of your boat design, so I can't say how much clearance or even if it is to be wedged in place, but assuming it is a smallsh boat (20 - 30 feet) a gap of 1/2 to 3/4" all round would be reasonable. But I must stress that this is dependant on the designer's intent for the rig installation.

I also assume that the "box spar" is hollow. If so, how were you intending to trim it down? Disassembly for re-cutting would be a pretty challenging task especially if it is glued with modern adhesives, and merely shaving away at the exterior would compromise the strength of the stick at a very highly stressed location. Be careful!

[imported_Jimmy]

Although the box spar should be hollow for most of its length, it is solid at the bottom. I don't know how long the solid section is on this one, but my old one was solid up to at least 7-8 feet from the base. My old mast had the aft side of the box removed (or not put on) at the base and was much more lightly built, at least on the sides so it seems like I coult still trim it a bit and still have it sturdier than the previous one.

One reason that I would rather alter the mast than the boat is that the current mast isn't what the boat is designed for and I will probably want to change it when I track down what the designer intended (round and hollow, I suspect). That might take quite a while though as the boat is quite old.

[imported_Jimmy]

I guess I have to post photos or something to generate any interest, but in case anyone besides "mmd" (thanks) is interested, I took a look at the beams under the deck. It looks like there is more than enough room between deck beams and shouldn't be a problem enlarging the opening, since it looks like at one point the boat had a round mast that had a 7 and 3/8" diameter opening at the deck.

[MAGIC's Craig]

Jimmy:
If you decide to open up the deck hole, and if you are planning to eventually build that lovely, tapered hollow round spar (gaff or marconi?)that your 32 footer calls out for, do, of course, your cutting with the future spar in mind. It is possible to make "wedges" simply and they can accomodate the square peg in a round hole problem without much difficulty.
Where in Nanaimo are you keeping her? (we are based down in Sidney - and will be coming through to Newcastle Isl. with the CRISR 2002 schooner races about July 17th - probably be 14-18 scooners out there that evening)
Bring your plans along and row out for a visit.

Craig and Vicky Johnsen
Schooner MAGIC

[imported_Jimmy]

My boat is at Anchorage Marina right now with a lovely view of Newcastle Island. I'm borrowing somebody's slip while he is working on his boat and I will have to move by the end of the month so I don't know where she'll be in July. Hopefully I will either have a mast on her by then or have made some significant progress in that direction.

[Jim Budde]

I'm not a pro, but in preparation for a large upcoming boat building project I 've read a lot about modification of boat designs .. my two cents is this ... if you cannot locate original spec's for mast, find an architect to guess-ti-mate what original might have looked like. Then build that mast. Hate to see folks cut holes in boats that later need to be re-structured. And down-sizing mast seems to be one of those things that shouldn't be done ... changes weight, perhaps strength, etc

Good Luck ... and no, you don't have to post pics to stimulate answers

[ 06-18-2002, 01:03 PM: Message edited by: Jim Budde ]

[imported_Jimmy]

There are a couple of photos of my mast partners at this site:

http://www.angelfire.com/indie/ealasaid/mast/mast.html

As you can see, the hole seems to have been bigger originally with blocks inserted on 3 sides to make the box spar fit properly. I had to replace them anyway since they were starting to rot from water leaking down the mast and this piece had cracked in half. I think I will just make a new one (and the one above it) with an opening that is the proper size for my new (used) mast. I will also make sure it can be removed later in case I decide to put a different mast on.