Inboard spinnaker/whisker pole fitting question

[Lou 14643]

My boat is an O'Day 272. I've just purchased 2 mast-mounted fittings (welded rings on a curved base plate) to receive the inboard end of a new (to me) spinnaker pole that I intend to use as a whisker pole on my genoa when running wing-and-wing down wind. The fittings came with fairly heavy pop rivets. Base plates are drilled for six rivets each. Total base plate diameter is about 2 3/4". My question is, should I have any concerns about twelve holes in the mast at the same height (in line with the boom)? I'm wondering about alternatives that would save me drilling the mast. For example, I've thought of creating wood cheek block bases (for want of a better description) that would be contoured to fit the curve of the mast. These I'd then attach either with some sort of band clamps around the mast, or long bolts connecting the two sides. This raises for me questions of the amount of pressure on these fittings, and the direction of the pressure. I assume that most of the effort is in compression (towards the mast) rather than tension (outboard). If this is correct, then I'd think screws would be sufficient to hold the fittings on the blocks. If there is a chance of high stress loading in tension (away from the mast), then I'd likely consider well-backed nuts and bolts.Someone may suggest using one fitting on the front of the mast instead of one on each side. I'm rulling that out, at least as a starting point, as the mast extrusion has a sort of flanged front edge, (likely designed for a sliding fitting car, for just such purpose) which I'd rather not drill into - it has a different curvature than the new fittings. Also, the conduits taking antenna and lighting cables to the top of the mast are just inside the leading edge, and I'd not want to drill into them accidently! I'd love to hear your thoughts on this.

 

[Stu Jackson]

You should only need ONE ring fitting

and it should go on the front of the mast. You might want to take a look at the Harken catalog or on line. This puts the screws in shear, no tension or compression. Suggest you take a look at some other boats with pole fittings.

 

[novelman17128]

whisker pole

I had a single spinaker/whisker pole base plate on my 22' Venture and found that it interfered with my 150 genoa when tacking in light wind, so I mounted two, one on each side (about 90 degrees apart) of the mast and have had no problems since.Novelman

 

[Rick]

One ring fitting

The HARKEN catalogue is an eellent resource. On our boat, we have one ring on an adjustable slide in the front on the mast and two rings on each side of the mast. The center ring is for the spinnaker/whisker pole and the stationary rings on the sides are for the reaching struts. As you think about your setup imagine the spinnaker pole moving forward as the wind moves forward. Utilizing side rings for the spinnaker pole could cause binding between the mast and spinniaker pole which can be under a considerable amount of stress. If the side rings were designed for spinnaker/whisker poles, you would see a fairly large number of boats setup accordingly. After reviewing other pole setups in your yard, you'll find that you would be the only boat with this setup. I am not that much of a trend setter to go against the studies of marine architects and engineers.

 

[Lou 14643]

OK, I'll go back to the drawing board...

to see how I can attach a fitting to the leading edge of the mast without risking drilling into the wiring running up the inside of the mast. Thanks for the feedback!

 

[novelman17128]

Spinaker pole mounting

Lou,That "flanged front edge" is there for mounting a sliding fitting with a ring. In this way you can adjust the inboard height of your Spinaker/genoa pole and have the best of both worlds (slide it to the bottom of the mast when not in use and out of the way of the genoa sheets and outer end of the sail, and to the correct inboard height when used.)Novelman

 

[Lou 14643]

Thanks Novelman, I realize that.

I think I mentioned it in my original post. I've not been able to find one to fit, and have instead found the fitting I've got, but realize it may not be ideal. Perhaps I'll have to invest in a piece of track and car fitting to install.

 

[novelman17128]

Inboard pole fitting

Lou, On my unit, both with one fitting and with two, virtually ALL of the pressure is straight into the mast. And, I can verify that after trying to release the whisker pole to set it on the other tack, I have to struggle to PUSH the pole out of the fitting.Novelman

 

[Roger (Ninette Manitoba)]

when drilling the holes for mounting

When drilling the mounting holes for your single mast ring (recommended) use a depth stopper for your drill bit. This is essentially a collar that is placed around the bit, (find them at a quality tool store). Set the depth for 1/8" or less and drill into the mast. The conduits inside should not be penetrated even if you were dead in line with them. Go dead slow with your drill so that you retain control throughout. Use a pop riviter or ss screws to secure the mast ring in place. As others have said, this is the traditional manner of mounting and does not seem to create issues of weakness at that point in the mast.When you attach your whisker pole attach it with the latch side up, so that when you detach it, it does not require lifting to disengage it from the ring.

 

[Blue Eyes]

Possible source for sliding car

Try Rig Rite - they list Isomat NG28 as one of the spars used on the O Day 272 - and they have info on others. I have purchased parts from them for the Isomat mast on my Pearson that I couldn't find elsewhere. Of course, you should try to confirm which mast is on you boat because O'Day may have used different suppliers or mast sections.http://www.rigrite.com/Spars/Isomat_Spars/Isomat_Masts/NG28_mast.html

 

[Bill Roosa]

Get the height right

Depending on the height of your Genoa clew, putting the rings at the height of the boom may not be correct. The rings should be at the height of the clew for whichever sail you use. A car would facilitate this and allow you to adjust for other sails if you ever decide to up your sail inventory.

 

[Lou 14643]

Thanks all for terrific advice!

Blue Eyes, this is in fact my mast. I had looked for this part, but obviously did not know where to look. Thanks for this perfect link. I'll be in touch with them to ask about cost (holding my breath!). Thanks all for your quick, insightful feedback!

 

[Blue Eyes]

Glad that helps - another source you might check

is Layline.com (link below) They carry parts made by Charleston Spar, the company that apparently took ove some of the Isomat product line. They don't list much on the website but if you call the 800# listed they may be able to help. They seem to be less expensive than Rig-Rite.http://www.layline.com/llf/llpages/htmlp72/page72.asp