Difference between cranse iron and mast band?

[Thorne]

From what I can see, cranse irons often have dropped loops whereas mast bands seem to have loops that stick out at 90 degrees or at least don't hang below the lower edge of the band.

Is this correct, or are the two items so similar in function and often custom-produced that the question is moot?

Some cranse irons are quite heavy unlike most mast bands, but other cranse irons seem relatively lightweight.

Just wondering, as on boats as small as mine I don't think there is any issue in using a mast band as a cranse iron or vice versa.

[Hwyl]

I've always called the thing on the bowsprit the cranse, and the thing on the mast, I tend to think of as the "hounds" or the masthead fitting, depending upon where you're talking about.

[Ian McColgin]

I'm with Gareth, but there are interesting regionalisms so it maybe that there are cranse irons liberated from bowsprits somewhere.

[Thorne]

C'mon guys, work with me here...

;0 )

I'm talking about the hardware sitting all alone, not in place on the spar.

Other than the potentially higher weight of the fitting on the bowsprit than on the mast of the same size boat, is there any other real difference?

[Hwyl]

I'd say a mast band (hounds) would look lie a castellated tower it it's upside down. Whereas a cranse would be a ring wit lobes (usually four). Id say that a cranse is usually on a shoulder, whereas hounds are usually screwed in.

The hounds would be a reasonably modern accoutrement, because traditionally (and much better), there'd be served loops at the top end of the stays.

As a preamble, I'd tend not to change things, that's why we call it traditional after all, and there are the evolutions of generations there.

Speculatively, I'd say the hounds were designed in such a way that no matter what twisting forces, the screw is always in shear. The cranse is always in tension and designed as such (especially the forestay/bobstay juncture.

[John B]

provided you get a fair lead off whatever shroud or stay coming off it, I wouldn't be too worried about using one for the other on your boat.

[Jay Greer]

A cranse, "crance" iron is a metal ring that is used to cap a bowsprit,"jib boom" at its end. There are eyes incorporated into the fitting for the leading of whisker stays, bob stays and head or jib stays
The Gammon iron is the fitting that attaches the bowsprit to the stem.
GI's are made in a variety of forms to fit the individual vessel and may incorporate a fitting for the attachment of the forestay.
A mast band may be exactly what the name implies and, may be used to secure a gooseneck, spinnaker track or the mounting of other hardware. Mast bands are, most often made of two piece castings that are connected by bolts. However, the form of the cranse iron may be used for the securing of stay and shroud attachments at the mast head, gaff peak, or at the end of most any spar. Hounds are more ambiguious in there definition as they are named differntely in
vessels of different size. Specifically in a square rigger they are the supporting structure for a top mast. In a small boat or yacht, they can be designated as the mast cleats that give support to rigging that is spliced around the mast.
Jay

[Thorne]

OK, I know that nautical fittings have many names, so maybe photos are in order.

To answer my own question, it appears as if the "average" cranse iron is heavier and wider than the average mast band, and the former often have lobes running back at a steeper angle.

This piece of hardware on eBay appears to be what the seller describes it as -- a SB cranse iron to fit a 3" spar. Not a bad deal if it goes for anything near $20.
http://i15.ebayimg.com/03/i/000/d7/74/ee11_1.JPG
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&sspagename=STRK%3AMEBTOX%3AIT&viewitem=&item=330209345341&_trksid=p3984.cTODAY.m238.lVI#ebayphotohosting

Here is what Port Townsend Foundry calls a Kranse Iron -
http://www.porttownsendfoundry.com/128fad80.jpg

Here is what they call a four-way Mast Band -
http://www.porttownsendfoundry.com/092af910.jpg



Here is what Classic Marine calls a 2-eye Heavy Mast Band -
http://www.classicmarine.co.uk/images_products/477.jpg

Here is what Classic Marine calls a Cranse Iron -
http://www.classicmarine.co.uk/images_products/479.jpg

Here's what TenderCraftBoats calls Mast Bands -
http://www.tendercraftboats.com/photos/fasteners_mastbands.jpg



Here's a WB Forum thread on the same topic -
http://www.woodenboatvb.com/vbulletin/upload/showthread.php?t=74034

[kc8pql]

Cranse irons have a tapered, conical hole. Mastbands are straight sided.

[John E Hardiman]

Cranse irons have a tapered, conical hole. Mastbands are straight sided.

I concur. A cranse iron is designed for the very end of a spar that has a large compressive load on it all the time that greatly increases with sail loading. A mast band is designed to hold a side loading on a spar, and that the increase in compression is an artifact of the geometry of the stays. A mast band will usally have other fittings above it, so a tapered opening may not work. For small masts either may work.

[Gold Rock]

Thorne, I've been making patterns for both items for years. I understand your question exactly. The fact is, based on the reasonable points you base your question on, the difference is often in name only, at least for very simple rigs. For instance, a very simple vessel may have a cranse iron needing only to support two whisker stays, a bob stay and a head stay. The same vessel might also require a mast band to handle only two cap shrouds, a back stay and a head stay. In a not unreasonable instance, this hypothetical boat could use the same casting for both applications. Fact is, we've accomodated many a small vessel just so. The two pieces tend to differ when rigs get larger and/or more complex. Commonly, a cranse iron will have two tangs in the horizontal plane for the whisker stays, usually drilled for a single pin each. In the vertical plane, the lower tang will have a hole for the bobstay toggle pin at the least. The bobstay tang might also be shaped to allow holes providing for a dolphin striker, multiple stays to the stem, netting attachments, etc. The upper tang is commonly a full length 'rib' allowing for holes for a headstay, a headsail tack, furling gear, or whathaveyou. Mastbands (the one piece types we're talking about here) have tangs shaped to their respective specific purposes. On the foreside, one needs attachment points for at least a headstay and a block for the headsail halyard. On the aft side, you have backstays, topping lifts, halyards, and more. That's just the simplest rigs. Once you get into spin. halyards, running backs, triatics, topsail requirements, etc., you can have all kinds of tangs of crazy shapes all over the place. Mastbands usually experience loads (excepting triatics and the like) at angles closer to zero than cranse irons. Stays, shrouds, and halyards usually approach the masthead at smaller angles than do the stays that attach to a cranse iron. Furthermore, blocks hanging from the fore and aft tangs on a mastband are best positioned so that they don't contact the spar when in use. The ideal shape of a tang maximally designed to handle these multiple duties tends to be of the "droopy" shape you observe. Hope this helps.

Chuck

[Hwyl]

Stunning answer Gold Rock. Thank you.

[Thorne]

Ditto, Gold Rock!