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Grand Canard

Bowsprit Retro-fit (in-hull)

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I bought a project J/27 that I'd like to retro-fit a retractable sprit into my hull; I'm searching for the fiberglass sprit part that is fitted and molded into the hull, been looking on-line but I haven't yet found a single company offering that retro-fit part as a stand-alone part or preferably as a complete kit w/ pole. Does anyone know of any companies that offer part or kit?  

Rick

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Just spitballing here but.....J-Boats?

Also, did you ask on J/Boat Anarchy?

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Look for retro fit kit for J-100 you will prob have to alter it

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8 hours ago, SloopJonB said:

Just spitballing here but.....J-Boats?

Also, did you ask on J/Boat Anarchy?

No, I didn't. I thought J Boats ( US Watercraft) is out of business and has been or is being liquidated.

Regardless, is there an aftermarket source?

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Why don’t you ask on J Anarchy like suggested? 

We didn’t liquidate that asset here.

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Does it have to be hull mounted? A lot more complexity with the external moulding.

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I'd suspect there are multiple issues with trying to kit a thru the hull sprit.

1.  Every hull/bow shape is different, so getting the outside the hull fitting (that holds forward bearing in place) to fit well means a custom fit every time.

2.  Alignment is critical, or the sprit will bind on extension and retraction, and getting the alignment right might well be beyond your average DIYer

3.  Alignment is critical, and you'd have to be very precise when you cut thru the hull...again, likely beyond the average DIYer...

I get the advantages of an in the hull sprit, (I had a J/109 at one time) but that said, I'd be pretty leery of trying it on my own, and I'm not usually to timid when it comes to boat projects...

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14 hours ago, Crash said:

I'd suspect there are multiple issues with trying to kit a thru the hull sprit.

1.  Every hull/bow shape is different, so getting the outside the hull fitting (that holds forward bearing in place) to fit well means a custom fit every time.

2.  Alignment is critical, or the sprit will bind on extension and retraction, and getting the alignment right might well be beyond your average DIYer

3.  Alignment is critical, and you'd have to be very precise when you cut thru the hull...again, likely beyond the average DIYer...

I get the advantages of an in the hull sprit, (I had a J/109 at one time) but that said, I'd be pretty leery of trying it on my own, and I'm not usually to timid when it comes to boat projects...

Guy in the yard had a retro done recently and alignment is off.  He had a buddy do it and I get the “...he didn’t pay attention to the shear...“  blah, blah blah speech.   Big piece of work too.  

Ouch.

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On ‎2‎/‎9‎/‎2018 at 12:55 PM, Zonker said:

Does it have to be hull mounted? A lot more complexity with the external moulding.

My J/27 cabin is gutted, nothing remains but bulkhead and ribbing; a thru hull sprit would look a lot cleaner, not clutter-up my deck.

I think it would be cool to fit my J/27 w/ thru hull sprit; I already re-cored my deck plus many other restorations, I am certainly capable of installation of the sprit.

I'm in Asia at the moment, but I will give J Boats a shout end of February.

 

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4 hours ago, Grand Canard said:

My J/27 cabin is gutted, nothing remains but bulkhead and ribbing; a thru hull sprit would look a lot cleaner, not clutter-up my deck.

I think it would be cool to fit my J/27 w/ thru hull sprit; I already re-cored my deck plus many other restorations, I am certainly capable of installation of the sprit.

I'm in Asia at the moment, but I will give J Boats a shout end of February.

 

Jeff Kent did a custom retractable sprit for his J-35. He has since sold his company to Moore Brothers in Rhode Island but still does consulting for them. I'd give the Moore Bros a call, although that might not be practical for you in LA.

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Custom Offshore in NJ did a custom sprit for an Express 37 if memory serves....

I think it would take a fair amount of thinking/mocking up.  I don't think its impossible, just more challenging then the ability of the average DIYer.  Not trying to say your not above average, or even not superlative as DIYer's go.

I agree that it is much cleaner and better looking...

J/80 pretty close in all respects to the J-27.  Wonder if you can find a sprit system from a beat up/trashed/salvage J/80 to use as your baseline, and then mod as necessary???

You might also be able to buy all the pieces of the J/70 system new...

If you do it, send us pictures!

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The hardest part of this might be finding the correct angle so the tip of the sprit is on centerline when fully extended....

Look at a Beneteau First 10r. It has a good retractable sprit. Works well and is easy to maintain.

It is basically a carbon fibre tube, inside a fibreglass tube, suspended on bushings. 

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Rich DuMoulin did one on his Express 37.  Maybe the same one referenced above.

Rumor is the yard did the job for $10K and said they'd be happy to do it again.... for $20K.  Urban legend.  I don't know real cost.

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get a stick of carbon tube as long as you need + .5. get another stick of tube, glass or carbon, a third the length of the first tube and a bit bigger. Take them to any engineer in the world and get 2 plastic bearings made with flanges.

Get a diamond blade for your grinder and chop a hole in the hull. make sure the shorter tube fits through and when the longer stick is in it, the end in on the centre line of the boat, stand back and make sure it doesnt look retarded.

grind the hull back on the outside and inside around the hole, fillet with glue, bog, mix then glass it before it sets, lots on the inside, some on the outside.

make up a plywood triangle that supports the inside end of the tube and goes between the deck and hull, fillet and glass.

Sand, paint, bang the bearings in on 5200, job done.

 

 

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As long as that first hole you chop in the hull is in about the right place, Alcatraz's approach should work...

If it looks retarded, you probably chopped the hole in the wrong place...:wacko:

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1 hour ago, Crash said:

As long as that first hole you chop in the hull is in about the right place, Alcatraz's approach should work...

If it looks retarded, you probably chopped the hole in the wrong place...:wacko:

At which point, you now need a bigger tube, perhaps a MUCH bigger tube

 

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or put it on centerline.

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So OP was talking about installing a a J-27.  So centerline thru hull would require some engineering to make sure loads from forestay are properly distributed.  Given relative closeness of J-27 and J/80, I still think you could likely take a J/80 sprit and housing, and retro-fit it to a J-27 reasonably easily...or use Alcatraz's approach, using measurements from a J/80 to approximate location (and shape) of hole thru the hull.  Its probably not too far off/different.

Other issue to address in this case is J-27 is rigged for a fractional chute...ISP is a 3 feet shorter than J/80 while J is 1 foot longer...so you'll end up needing a custom built asym that is a little on the "short and squatty" side...

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For drilling the hole somewhere, see if you can find a shop with a sidepower tunnel cutter or similar (mostly used for bow thrusters).   They are basically a die grinder with a precise centering rod that goes through both sides of the boat so you can drill your pilot hole exact and then someone else can run the grinder to chew through.  Many places will cut the hole on your pilot for cheap(I used to charge 50$).     Use a long and straight rod the size of the centering rod, same length as the sprit will be outside the boat.  Do your mockup and setup with that, then drill the hole exactly in line with the rod.   Let them run the cutter through, and you'll have a nice neat hole in exactly the right place, and pretty close to the right angles to fit your tube in, lot easier than the horrible mess people make with sawzalls and grinders, because you've got the hole to support your tube and this leaves you the most original glass on the hull, with a little hand adjustment you're ready to go.   When you first see the weird oval looking hole after it's cut you'll wonder if they screwed up, but then you slide in the tube and it fits perfectly.  I've never done a sprit, but I've done spare prop shaft holders and other tubes this way as well as cut tunnels for thruster of course.   

EDIT: Also if they charge by the hour to use it, ask if you can use a carbide bit that you supply instead of the factory diamond dust one.  Little hard on the grinder, and burns up a bit, but the 12$ for a bit is a lot cheaper than the shop rate. 

 

 

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I did a similar install last year for my Beneteau Figaro.  I purchased a carbon sprit and fibreglass tube kit for an Archambeault 31.  I CAD'ed up the bow (top view only) and determined the location of where I wanted the extended pole to be.  Then I worked backwards to find the length of slot I needed to cut in the hull and where it should be placed.  The intersection of a cylinder and an angled plane (approximate bow shape) is an ellipse. The hull sheer really doesn't matter as the intersection is still an ellipse.  Once the length of the ellipse was determined, the height is known from the outer fibreglass tube diameter.  I then cut a template of this ellipse size out of thin plywood, glued it to the hull, and proceeded to cut it with a router and edge following bit.  

Once the hole was cut the rest was easy.  Just a matter of sanding the hole, angling the edge, then glassing in the outer tube both on the inner hull and the outer hull.  I also glassed on a plywood backing to the inner hull to support the load. The outer tube is also supported by a bulkhead I had to install on the inside of the bow about 4' from the bow. It is glassed to this bulkhead as well.

The kit I had also included an outer fibreglass cover.  I sailed the season without it, but installed it late last year.  It was the most difficult part to install as it needs to fit the hull very closely.  I'm still not done the final work, but it's 95% there.  

In the end, it was a lot of work, but more prep work than actual busy-work. I wouldn't hesitate to do it again, the boat is a lot more fun to sail with a much bigger kite now.

sprit.jpgIMG_0471.JPG

 

IMG_0688.JPG

 

IMG_0561.JPG

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There is a reason why J/80s have a bulb on the bottom to keep ballast low. The question is whether the J/27 has the righting moment to handle a big A Sail. I can imagine the 27 would go sideways a bit on a reach with this configuration. Then again I could be wrong.

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J-27 actually carries more upwind sail area (364 sq ft) than a J/80 (338 sq ft) and more ballast (1530lbs to 1400lbs) and has a shorter ISP.  Bulbs are really about keeping the same righting moment while carrying less weight.  All that said, you'd likely need more crew weight on the rail of the J/27 compared to the J/80...

But I'd bet it'll carry an asym just fine...

 

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Crash -J-27,1530 ballast/3800lbs displacement. J-80 1400lbs - 2990lbs displacement. 48% ballast/displacement vs 40% ballast/displacement plus J-80 carries its weight lower.  Pretty significant difference.

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Concur, and the J/105's is around 44%... but if you look at most (newer?) boats with bulbs, the ballast/disp ratio is around 37 percent or so...J/70 is 36%, J/111 is 38%, my J/109 was 36%.  But I was mostly trying to say that despite the lower ballast displacement ratio, the 27 carries more upwind sail area...and that you can "get or gain" the ability to carry more sail (area) with movable ballast like crew weight (up to some limits of course)...or i guess even water ballast a la the J/121.

 

 

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Had a sprit and A sail on my Capri 30. Worked fantastic. the J27 should be much the same, although you should think about putt a jumper strut on the rig and run masthead chutes...

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Sprit: good idea (get rid of idiotic symmetric chutes -- christ, that dumb idea was to work around goofy rating rules of a hundred years ago)

Retracting through the hull: bad idea (cost, weight, leaks, low strength, high flexibility so only slack luff sails)

Sprit length: probably can't be too long (100% of J is not too long, common on skiffs, mini 650s, but still rarely seen in the northern hemisphere)

On my Olson 40, still putting this together, for a total cost of a couple of hundred dollars:

  • Sprit is the full length 100% J carbon spinnaker pole, with original inboard end (Forespar dildo) and simple lathe machined end fitting (to be fabricated)
  • Inboard end of sprit now mounted on the bow centerline just forward of the jib tack using a simple SS welded fitting for the Forespar dildo
  • Bobstay (to be) installed just above boot top running to forward end of pole (hold end of pole down)
  • Side-to-side location of pole fixed by whiskers from end of pole to toe rail near the mast
  • Weight of pole supported with lines running from middle of pole to top of bow pulpit. These also keep a rolled and not-hoisted a-sail or code zero out of the water.

I did an experiment last year on a Santana 3030GP (Creeper) and the boat could still be made to broach with a 75% J sprit in moderate air (say, 12-15 knots), so that fat round MORC boat needed a longer sprit.

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Looking to add an external sprit to my vessel (bow compartment is the anchor rode, not deck accessible). 

Would like to provision a bob-stay to tension, allowing tighter luff than an unsupported strut. 

Any suggestions on where to find hardware?

 

Lacking any better idea, thinking of something like a Shaeffer SS Chain Plate 

Might have to go borrow a forge and anvil and bend it to the bow's curve.

4 3/8" bolts in shear should suffice to carry the load. 

 

 

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On 4/25/2018 at 2:29 PM, carcrash said:

Sprit: good idea (get rid of idiotic symmetric chutes -- christ, that dumb idea was to work around goofy rating rules of a hundred years ago)

Retracting through the hull: bad idea (cost, weight, leaks, low strength, high flexibility so only slack luff sails)

Sprit length: probably can't be too long (100% of J is not too long, common on skiffs, mini 650s, but still rarely seen in the northern hemisphere)

On my Olson 40, still putting this together, for a total cost of a couple of hundred dollars:

  • Sprit is the full length 100% J carbon spinnaker pole, with original inboard end (Forespar dildo) and simple lathe machined end fitting (to be fabricated)
  • Inboard end of sprit now mounted on the bow centerline just forward of the jib tack using a simple SS welded fitting for the Forespar dildo
  • Bobstay (to be) installed just above boot top running to forward end of pole (hold end of pole down)
  • Side-to-side location of pole fixed by whiskers from end of pole to toe rail near the mast
  • Weight of pole supported with lines running from middle of pole to top of bow pulpit. These also keep a rolled and not-hoisted a-sail or code zero out of the water.

I did an experiment last year on a Santana 3030GP (Creeper) and the boat could still be made to broach with a 75% J sprit in moderate air (say, 12-15 knots), so that fat round MORC boat needed a longer sprit.

Hey Carcrash, 

You have any pictures on what you did to your olson bowsprit? I have a olson 911 that I race hard and am playing with different bowspirt configurations. 

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On 4/25/2018 at 11:29 AM, carcrash said:

I did an experiment last year on a Santana 3030GP (Creeper) and the boat could still be made to broach with a 75% J sprit in moderate air (say, 12-15 knots), so that fat round MORC boat needed a longer sprit.

How does a longer sprit and I'm guessing more sail area make you less likely to broach?  Or are you using a smaller kite and just trying to get it way out in front of the main?

The load on your "whiskers" is going to be considerable, it seems like it would be ideal to add spreaders and intermediates.  You are talking about 32' long whiskers connected to where the hull is about 8' wide.  That sounds like the loads that shrouds would see on a 22-25' boat.

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10 hours ago, ENTOURAGE/OLSON911 said:

Hey Carcrash, 

You have any pictures on what you did to your olson bowsprit? I have a olson 911 that I race hard and am playing with different bowspirt configurations. 

Recommend the Trogear sprit, easy to install, no deck clutter, and it’s removable if you go with the quick pins on the through bolt.

A7DEC774-E2A1-41BE-8BA4-CD9ECD13AE14.jpeg

324F15B8-2B9F-4094-93F2-0FE1D8FCD2E1.jpeg

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11 hours ago, Crash said:

Can't see without a login

 

Sorry, did not realize a login needed.

The pole is 2.5 ID 1/4" wall, heavy sucker, but this is all uncharted territory, so to speak, I decided to go heavy. I had it powder coated. There are 2 Delrin bushing on each end of the launch pipe, that were machined at a the shop. The pole slides effortless inside the launch tube. There is also one Delrin bushing at the end of the pole, where the bobstay line exits. The bob stay line and the pole extender lines are both T900 line, practically no stretch or creep. 

The pole, including the powder coating, was about $80.00. The launch tube was about 75.00. Bungees an other fittings about 50.00. Line was on sale at West Marine 40% off. So the total material cost was a little over 250.00 give or take. 

The rest was labor and a know how that my friend provided. I did all the grunt work, i.e. grinding, sanding, while my friend did the rest.
BTW my friend, owns a boat building yard, so I had access to his tools and knowledge, but it was not a complicated job.

I added an cheeks block at the aft end of pole (not shown in pics) that helps retrieve the bobstay back in the locker when pole is retracted.

The launch tube came from here:
http://www.fiberglasstubingsupply.com/shop/inner-diameter/3-id-3-5-od-fiberglass-tube-5-long-white/

I machined the two launched tube bushing from white Delrin. The pole end bushing is from black Delrin.

 

 

 RJAzSvM.jpg

 

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