Best choice of hull hardware these days??

[DN5135]

I am ready to start adding hardware to one of the new hulls we are building and I am wondering what the "in" choices for set up are these days:

What is the best adjustable mast step installation used today (weight and ease)?

What is the preferred plank attachement...inside or outside the hull, one stud per side or two?

How long of a block tube on the back deck?

Anybody tried to make the front chock & steering post out of aluminum?

How short of a bob stay post is practical?

I've always used a full length bob stay because I felt the strength is better (mast down force, blocks on back pull up) what' the idea these days?

Could the front tang be Aluminum, maybe 3/16"...much easier to fab at home and lighter...how about if a stainless insert is used in the forestay and bob stay pin locations?

Are people using the tiller straps or the tiller tube?

Thanks for any input on these questions, or any other comments for that matter.

My hull is poplar and weighs 54 lb epoxy coated, but w/o hardware. I need to keep the hardware light!

[Geoff Sobering]

If you're going to fabricate the forestay fitting and weight is that important, you might consider Carbon fiber.  I believe some (all?) of Jeff Kent's hulls have a Carbon-fiber forestay fitting.  You could probably lay one up yourself without too much difficultly.

I really like the mast-step fitting that Clinton Renji sells.  It has a series of holes that accept a post-like fitting with the mast-step ball machined on the end.  I'm sure there's a photo around somewhere.  Maybe Lou Loneke or Jane Pegel from Lake Geneva can help with contact info. I think Dave's Machining also sells a version of the fitting (but Clinton's is cooler!).

I don't know if Jeff Kent sells the mast-step for his boats separately (it may require some in-hull hardware), but it's particularly simple, a carbon plate with a series of holes that the mast-base can be inserted into.  Northwind Iceboats may sell it.

I believe Ken Smith has an Aluminum steering chock; he may be able to comment on its desirability.

I think most people use inside attachment plates these days for the plank (aka the "alternate style"), but you need to have the blocking in the cockpit area to screw these into.  I've seen both single and double-stud plates around; I believe Northwind sells the double-stud hardware (along with a bunch of other European-style pieces - I recommend his stainless steering chock).

Cheers,

Geoff S.

[DN5135]

Geoff, Thanks for the info. I didn't realize carbon was ok as a replacement for some of the metal parts, that would be an easy build and cool as well.

Is carbon acceptable for chocks as well? how about the tiller hardware?

[Geoff Sobering]

Is carbon acceptable for chocks as well? how about the tiller hardware?

I just checked the Specifications Section I Fittings, item 13 says, "The side chock and the steering chock shall be made of steel, stainless steel or aluminum".

I'd suggest you become pretty familiar with the specs document as you contemplate non-standard hardware; it's really pretty easy to figure out after a bit of reading.

I just checked http://northwindiceboats.com/ and they have a light-weight front tang fitting: http://northwindiceboats.com/?Section=Details&ProductID=156 but I don't see any listing for the Kent mast-step.

Cheers,

Geoff S.

[DN5135]

Geoff,

Yes, after I posted I took a look and that one is clear although I don't think it makes sense. These days it is pretty easy and cost effective for the home builder to work with composites. It is actually more practical than some of the metal fab. The tech committee should reconsider some of the older rulings!!

You can purchase 3/4 balls on pins, so a plug in style aluminum base with detent stops in it would be an easy fab. I think I'll look at that as well. 

I am trying to get some custom F channel extruded to make chocks, the side chocks would be simple cut offs with some trimming and the front could be fabricated using the same stock. Otherwise I will weld up aluminum angle.

I like the idea of the carbon fiber front tang. I think I'll fab out of aluminum and coat that rather than molding carbon only.

Thanks again!

[Bob Gray]

  First of all if you are going to buy hardware, it's hard to go wrong with Sarns hardware. Most of the top U.S. sailors are using it. There is nothing wrong with making your own however let me give one piece of advice. We are having a problem with the hounds on our masts. The stress of the pull on the head stay is so great that the 1/4" hole for the hound attach fitting is being elongated. Drilling the hole to 5/16" seems to be helping. You have the same stress on the front tang so be careful what you make it out of.   Bob

[DN5135]

Bob,

Wow, I can remember switching from 3/16" to 1/4" on the pins and from 1/8 to 5/32 on the forestay.  The new setups are generating that much stress? or is it the lack of snugness between the adjuster and the tang that allows the pin to elongate through initial bending??  I noticed years ago that I needed to keep the pin short so that the tang was snug between the adjuster strips to prevent bending. Fact I used to put a couple extra pins in above for 2 purposes, extras and to prevent spreading.

Thanks for the info., I'll have to watch my adjusters, I made a bunch of them about 5 years ago when I had access to a turret press. I went with 1/4 for the fore-stay and 3/16 for the shrouds. Also, I have nicro press equipment and have fabricated the stay and shrouds with this using 2 compression fittings per end. Do you think I need to scrap that and go with swage fittings?

Thanks....I am looking forward to to attending some regattas nest year to see what you guys have these days. Next week during our weekly boat building session I am going to pass out membership forms and attempt to get all of the group sail numbers and back into the association! Maybe we can get ourselves organized here for a little friendly competition.

[Geoff Sobering]

The new setups are generating that much stress? or is it the lack of snugness between the adjuster and the tang that allows the pin to elongate through initial bending??

It's not the pin that deforms but the metal in the hound fitting.  I've seen at least one where the hound actually ripped apart from the load.

[Geoff Sobering]

I'll have to watch my adjusters, I made a bunch of them about 5 years ago when I had access to a turret press. I went with 1/4 for the fore-stay and 3/16 for the shrouds.

Also, I have nicro press equipment and have fabricated the stay and shrouds with this using 2 compression fittings per end. Do you think I need to scrap that and go with swage fittings?

I've been using Nicro-press fittings for many years.  On the side-stays there's no problem with a single sleeve.  On the forestay I've been using doubled sleeves without a single failure.  The load does deform the 3/16" thimble.  Bending the 5/32" 1x19 wire around the thimble and crimping the first sleeve is a bit of a job, but I've done it myself a few times now.

Cheers,

Geoff S.

[Ken Smith]

Good advice re sources and being wary as loads are high. 

The chocks you can fabricate would work, but not be durable unless you added strength.  The leeward runner exerts huge side forces into the chock.  Most of the available parts have stiffened or reinforced brackets between the chock side and base on the inboard flange.  Some are even stiffer, hogged out o solid billets.  There is more info out there and check the pictures on sites like Iceboating.net.  Allowing carbon and changing specs is not a tech committee issue, it is a procedure in the bylaws.  It is an onerous process on purpose.  Gradual evolution with the concurrence of the active members is a good thing.

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Incomplete and not-as-informed advice re swage.  Lets define terms:  a nicropress fitting is a swage fitting that looks oval before installation and is pressed into round sections by the tool.  It comes in copper and in alloys that look silver.  They conform to technical specifications that require the properly-formed fitting to be as strong as the wire.  If you do  a tensile test, the wire breaks before the fitting fails or the wire pulls out.  That is strong enough for me, who needs two?  Critical visual inspection tips:  The end of the wire should not be buried in the fitting.  Two "presses" with the tool is the usual recommended practice.  More may make a pretty fitting, but may also cause internal cracks in the material work-hardened in the first licks with the tool, which weakens the fitting.

A rolled or formed swage fitting is usually a stainless steel cylinder that the wire is put in, then the cylinder is formed in a roller or die to bring the cylinder into intimate contact with the wire.  Similar technical specs apply regarding strength, but more depends on the skill of the user.   Strength depends on proper deformation, porper insertion and not-excessive forming.  Specifications often require a proof test pull on each fitting as a QA check.  The tooling in high-quality (aircraft rigging and military spec) shops includes a go-no-go gauge.  The cylinder must be squashed to the wire enough but not too much.  The go-guage won't go over the formed part unless it is enough, and if the no-go portion goes over the formed part, it was deformed excessively and may be subject to cracking.  Your visual check is for longitudinal cracking in the formed part and broken wires just outside the formed part.

[Geoff Sobering]

a nicropress fitting is a swage fitting that looks oval before installation and is pressed into round sections by the tool.  ... Two "presses" with the tool is the usual recommended practice.  More may make a pretty fitting, but may also cause internal cracks in the material work-hardened in the first licks with the tool, which weakens the fitting.

The number of "presses" depends on the size of the fitting.  For the 5/32" and 1/8" wire used on DNs three is the most common recommendation (although some tools use two crimps on 1/8" wire).  The sequence is pretty important, too:

http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99c827db9baac81b86256b4500596c4e/$FILE/Chapter%2007.pdf
(pp. 32-34)

When using a sleeve requiring three compressions, make the center compression first, the compression next to the thimble second, and the one farthest from the thimble last.

http://www.bosunsupplies.com/NicopressSwage.cfm

When crimping sleeves that require three crimps, crimp the middle first, then the thimble end, then the standing part end. This lets the sleeve expand away from the middle, preventing internal stresses. For sleeves requiring four crimps, start at the standing-part side of center and work toward the thimble. Finish with the standing-part end.

Cheers,

Geoff S.

[DN5135]

Thanks for all the replies.

Ken, do you have a aluminum front chock?  If so, is it working out for you and did you do any special reinforcing?

[Ken Smith]

I have an aluminum front chock on one of the older boats.  It is formed of three pieces, and was originally a Russian bit of hardware.  The shaft is stainless and has a cap screw that comes through the other two pieces to hold it all together.  The piece that captures the runner appears to have been machined from a casting.  The arm to connect the steering rod fits into a milled slot on top of the runner-capture piece.

It has held up over about six years of hard service but is developing a little slop  the pieces just are not so tight anymore.  I added a pin in the aft end to limit the amount the front can hang down, to keep the tail of runners from punching through the bottom of the boat.

Advantage to me:  It came on a hull I bought. 

Advantage over steel:  very small weight advantage.

Disadvantages:  The bearing is larger diameter, so cannot be easily replaced.  The slop developing as mentioned above is a consequence of an assembly rather than a weldment.

Incidentally, it was advertised by the seller as titanium, when that was legal.  When Ti became illegal, I put some filings in a scanning electron microscope and got an x-ray spectrum (perk at work), and it is not Ti, it is pure Al.

[DN5135]

Thanks for the reply. I was thinking of a welded design.  For me, Aluminum is much easier to work with than stainless, I was actually thinking of replacing a lot of the stainless sheet parts with aluminum. In some cases with f/g prepreg reinforcement.

BTW...It sounds like we have the same kinds of toys at work!

[Ken Smith]

No matter what you do, you will need a steel shaft and bearing.  The Al chock has more beef int eh top corners and teh side plages are thicker.  I can measure if you want details...  Otherwise, if teh chock can deal with teh stress, by being sized properly, I see no problems.

Ken