The ultimate Tandem Island (hydrofoils, Spinnaker, jib, etc)

John:
That's what I did with my spray skirts, I wrapped them around the alum tubes and just fold them over the bow when transporting, holds all my sails and rigging down when on the highway.
Here is a pic of my spray skirts ready for transport on the highway.



Bob

I did some work on the bow frame today after work. Tomorrow I will take it off the trailer and see if the furler works.





I still have to cut the u-bolts to length and re-jig the spray skirts.

John, one last comment regarding the bow "wing piece" below your square tube. The piece with the line that wraps around the front of the bow. You probably could safely remove that. Surprisingly there is very little stress and movement on the bow connection. The force of the wind on the jib with my setup is pretty much transferred to the aka cross bar. In fact my attachment of the frame to the bow eye strap (where handle attaches) is merely a loose shackle. I was kind of surprised how this worked out.

The reason I'm commenting is I see your rigid tight attachment to the bow as a possible impediment for transferring load to the aka cross bar. It might, in your setup be borne more by your bow. I'm not an engineer but you can see what I mean if you disconnect all your bow connections and just use a simple heavy duty plastic tie strap between the frame and handle shackle. Then simulate the jib force by pulling on your jib while set up on the trailer and observe how the load transfers to the aka cross bar. You'll see how a plastic tie strap actually doesn't get much stress on it. I've used plastic tie straps as connectors in the past while sailing and they worked fine. After testing I opted for a loose stainless shackle which allows me to remove the frame from the boat easier.

I'm not at all an expert and just giving you something to think about here.

John:
Really nice workmanship.
What I did on mine when done was clean and clear coat everything with clear spray paint, especially all the screws and screw joints (where they touch aluminum).
Jim is correct you want to transfer as much force to the aka bar as possible. The only reason I have that extra plate on mine 1 ft back from the front is so I an lift the entire boat by the end of my long bowsprit. Keep in mind my design was a little different because I had two short and two long bars so I kind of needed that piece. With your better single bar design that plate is probably redundant.
Bob

Here was me worried that I may have under engineered the bow brace. I gave the furler a test out this morning and the sail furls no problems. I'm not sure how it is going to go using it the reef the jib so the the clew clears the mail sail. At least I should be able furl the jib completely if things get a bit hairy. I forgot to take photos as I was in a hurry to get out of the sun. The temp hit 39 C (102 F) here yesterday and is looking to do the same today.

Once I'm happy with everything, I was going to use Duralac on all the fasteners to hold back corrosion on the dissimilar metals https://whitworths.com.au/main_itemdeta ... item=59733

John:
I don't think you need to be concerned about the clew on the jib being behind the mast, most of my jibs end up that way, (and pretty much any sailboat with a genoa sail). Your jib never points straight back in the middle, and when you switch tacks the sail is loose and just slips past the main mast, shouldn't hurt a thing.
Bob

"Over-engineered" is no sin where I come from.

You'll get your best tacks if you keep some tension on both sides of the clew, rather than letting it flap. On the big cats, most folks backwind the jib a bit, and then ease it across. I don't know how this will translate on the little tri. Could be a little tricky at first to use the hand tiller and work both leeward/starboard sheets. But you'll get the hang of it.

If you are still planning on hanging blocks from that metal clew, these will extend even further and drag across all sorts of stuff as you tack. In big wind, they will bang things. Battens tend to hang up on things too, as they come across.

Let us know (see) how your sheeting system works out.

I took the AI out for a test this morning and all went well. The morning started off dead calm with only the occasional very light puff. I was thinking I wouldn't get to test the jib out but that soon changed as the wind picked up.



As we all suspected the sail is way too big so I'm glad I was able to reef it on the furler.


I was glad I took the time and made up some hakkas. What a blast sitting out on them. If i didn't have them then I would have had to furl the sails even further. I didn't get any photos when it got real windy as I was hanging on for dear life. The AI was screaming along at times.



Looking at the photos I just remembered that I forgot to take the front strap off the bow brace.

Beautiful work John.

You're going to love those swivel cleats, hiking out there on the Hakas.

Gonna be a rocketship. Don't forget to wear your seatbelt.

john

one more thing.. if I may.
Our marina where we store the boat is closed until later in January and we have found we cannot get the boat out. Can you post the dimensions that you used for your mast topper please. diameter of tube, length and the front and rear overhangs. at least i can get on with that and make some headway.

cheers

trevor

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May the odds be ever in your favor..

Very nice work John and great to see you go with the aluminium haka option!

It sure was fun and I was thinking about a seat belt.



The top part uses 32mm OD SS tube and 12mm SS rod. The rear stay is 600mm from centre and the front is 300mm. Although the front could be shorter. I have the jib attached at 130mm out from centre and I'm thinking I might bring that in to 60-70mm. I would go with Bob's design using a point bearing set up rather than the tube as I did find there is a fair amount of friction furling/unfurling the main with mine.

The SS Tube that goes on the mast has ID of 34mm



Yep, after seeing yours and having the big green store just down the road, it was nice and easy to put together.

Even BETTER you are, of course, metric!

thanks

Trevor

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May the odds be ever in your favor..

John

the 32mm is that the bit fits on the mast of the rotating topper.

Sorry if i had mine here i could measure it!

CC

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May the odds be ever in your favor..

Its the upright tube the 12mm rod is attached to.