Hi,

I´m building new beams from scratch and have a mast with Taipan/Capricorn mast base.

Have a few questions about the striker rod and mast step cone of this beautiful Taipan. Can anyone help me?

Taipan



Brgds
Lars

G'day Lars what size Taipan, I have a new mast base for a Taipan 5.7 I'm about to put on a boat and can take a series of photos if that's what your after, I also have the same already on my 5.7 so can take photos of that as well. If you have a 4.9 I can probably get photos of my mates. Might help if you tell me specifically what info your after

Hi Jeff,

As I recently retired from work I finally have the time to take care of my projects.

I am actually building new beams for my Nacra 5.5 with 10.5ft wide, 100x3mm beams, F18 rig and daggerboards.



As my F18 mast has a Taipan/Goodall mast base with cup, I want to build the cone and striker post in the same fashion. But will not use the hinge. Have had contact with Andrew McPherson and got advices from him, but I would really like to see how it is made IRL.

I´d really like to see how the post with cone is adopted to the beam. Will also add the C2 tensioning bolt at the bottom of the striker post. and would like better images than in the C2&Viper manual.

Will be grateful if you can supply a few images.

This is my guesswork, please correct my mistakes:



Brgds
Lars

I have taken photos but have run into the problem of file size I'll work on that

If you use Windows you can do it in MSPaint and if you are a Mac-guy you can click the tool button when you have opened the image and resize it there.

Or you ca E-mail me: lars at soderquist.se

Brgds
Lars

I presume the tip of that cone is not as sharp as your drawing? Seems a small point like that may help provide room for mast rake, but might focus forces on a very small area of mast base?

Right, Jay, I am not that exact when drawing in MSPaint ;-) . IRL It will be a Goodall/Taipan cone. My guess is radius ca 3mm. Checked my Goodall cup with a 8mm diameter ball and it is anyway less than 4mm radius.

About the striker strut, my new guesstimate is 7/8" 10 swg.

Lars, are sure that these beams without inner enforcement will do the job? The same applies to the attachment on the hulls.
10 feet width is considerable.

No prob Ronald, there will be 400mm sleeves inside the ends and also a sleeve inside the middle of the main beam. Actually a total overkill. These beams are actually 0.5ft narrower than the Nacra 18SQ that used 100x2mm without any reinforcements at all . There will also be a stainless 40x3mm dolphin striker.

Okay Lars. I was a bit worried because about 25 years ago I've worked with the (old) Nacra tubes when restoring a Patin a Vela cat.
Replacing its fixed wooden bridge by mountable aluminium beams, which were by the way half of your length!
I was given for free a bunch of damaged Nacra beams by Jan de Boer, the dutch Nacra importer.
He had a lot of those beams standing in a corner, all damaged or broken off just where the dolphinstriker is attached next to the hull.

In order to correct that failure Nacra has later on started to use more inside enforcement, especially in that place. So, it is stricly speeking not an overkill to use sleeves inside.
Galvanic corrosion stays a problem however at that particular place.

In the modern F-cats from Nacra there is a considerable enforcement inside the beams but I don't know if that goes all the length or just by short sleeves.

Bon courage with the restoration.

Northsea,

The N17 Mk. 2 and F20c from Nacra both have substantial inside reinforcements where the beams meet the hulls and at the center sleeves. Upgrade kits are available, and Nacra have standardized some of this across the range (i.e the F18 Infusion gets the same beam as the N17 Mk. 2 nowadays, though the stock beams work fine and haven't given me any issues). There were a handful of 10' beams broken on the early F20c's, perhaps those are the beams the dutch importer had lying around? I would definitely advise the O.P to go for substantial reinforcing though with a F18 rig I don't think you have the power that the F20c has and frankly the 10' beam is overkill (it just means you'll be in the trapeze in 12-13kts of breeze instead of 10 kts as an example).

Hey Sam,

You are absolutely right about reinforcements, they are really needed though 100x2 with 3mm sleeves would be enough for the main beam.

Hi Sam,

Thanks for all your Nacra info.



But I cannot completely follow you here.
If you are sailing on flat water with a 10 feet platform, you can have more fun by taking for instance your grandchildren (or even grandgrand children) with you.
The more surface on your platform, the more social opportunities.

If you are sailing in waves at sea, in my experience, you feel every inch of more beamlength. I cannot explain this here theoretically, but with a labile equilibrium it comes to the millimetre.
I discussed that once with the Dutch Nacra people in Scheveningen and they totally agree. Thats also the reason why in the design of the F17 they broke with the 2.5 meter barrier, the famous legal roadregulation.
So, also here counts the more inch in the beam, the more fun. I wouldn'd call it an overkill.

Downside however is, you cannot tack anymore when it is too much!

the cone is fairly blunt you could easily make one by using a stainless steel bolt of the correct size and welding on top of it with stainless welding rods to form the cone, the finer tip is really just so the mast will rotate, my Nacra 18 square is 11ft wide the width makes it more stable but on a 5.5 with two people I wonder if you need the extra righting moment as that makes you much slower if you don't fly a hull, great project keep us in the loop

Will set up a threaded rod in the lathe to form a cone. Have taken measures of if from a photo I got from Andrew.

Actually tried my concept with the 5.5 with original rig last summer. We then used 115cm wide and low foldable wings, that lifted to leeward when sailing.

The wings where great but we felt wider beams(320cm) and narrower wings(80cm) was the solution, resulting in a width reduction of 10 cm, although righting moment gets a little higher. Might go down to 305cm if things gets boring.

The new higher F18 rig will give slightly more heeling moment. Will also experiment with a slightly bigger jib made from a cut down 49er jib, going lower to the rails. If this isn´t enough I also have a Marstrom Tornado alu rig lying around.

This is my ready built Taipan style front beam, resting on my 5.5 hulls. Cone radius is 3mm, fits perfectly to the Goodall mast base.

Below is also the final striker post design. NOTE, it is not at all to scale ;-)!

I´ve also bought an Inter 20 main for another mast I already have, and I am also waiting for a pair of Nacra 6.0 hulls to be delivered from the Netherlands.

Will combine this with a flattened self tacking 49er 5.7 sqm jib and the newly built 10.5 ft beams.

The 5.5 keeps the F18 rig and its original beams.