Replacement pivot point in the join ama-aka DragonFly 1000

[Tuca]

Hello,

I'm from Spain and the new owner of Dragonfly 100 "Tuca", number 29. I have the boat from a few months ago and keep learning.

This weekend I have found broken the join from ama to aka, is a M20 screw. Question is how can this part be replaced. From inside the ama, evering is cover from glass fiber.

On to the ama is the round teflon part where the ama pivot.

In tha aka access is really easy as there is a circular cover on top. (sorry don't knownthe name in english?

Question is how can I access to the join on the ama? Will really apreciate any help on this.

Good sailing to everybody

[Double Horizon]

You will need to grind the fiberglass from underneath until you get to the metal frame that the M20 bolt is welded to. Try not to go all the way through to the outside.

This is a big dirty job. Best to dismount the ama and work while it is on its side, wearing protective suit and high quality filter mask with full face shield. Cover all your skin, the fiberglass dust is very bad.

[Tuca]

Hi Larry,

Thank very much for your answer. It really help a lot.

I have some experience with fiber-glass, so I think that can make the reparation myselft.

For dissasembling the ama I think that I need just to remove the bolt from the other aka and remove the back stays.

Boat is on water right now with the mast up. Do you thing that would be possible to attach the backstay and an extra halyard to the stern deck cheat without risk of the mast falling down?

Also would the boat be stable enought without an ama to stay on water for 7-10 days mean while I make the reparation?

Thanks

[Double Horizon]

(edited) NO NOT "stern deck cleat", you could keep the mast up by securing the spinnaker halyard to the end of the aft cross beam on the side to be repaired, in place of the backstay. I have replaced backstays that way, one at a time. The boat MUST remain unfolded during his operation.

(Make sure you secure the halyard at the winch in a way that takes extra effort and multiple steps to release, and place a sign to make it very obvious to anyone else who might board your boat that they MUST leave it alone.)

If your boat is in a protected area it should be OK with just one float, but I would tie the remaining ama close alongside to a dock if any strong wind is expected, just to be sure. Also, I would not trust a spinnaker snap shackle -- use a knot at cross beam attachment.

[Double Horizon]

I just read your post again - NO NOT "stern deck cleat"

You MUST attach to the outer end of the cross beam while the boat is UNFOLDED. Don't even think about trying this unless the boat remains unfolded.

[Tuca]

Ok, I understand that 2 things important:

- Spinnaker halyard to the end of the aft cross beam on the side to be repaired
- Boat must be UNFOLDED

Both AMAs unfolded?

Will do that way for sure, even I don't really understand why it's son important the unfolded condition.

Thanks again.

[Double Horizon]

Ok, I understand that 2 things important:

- Spinnaker halyard to the end of the aft cross beam on the side to be repaired
- Boat must be UNFOLDED

Both AMAs unfolded?

Will do that way for sure, even I don't really understand why it's son important the unfolded condition.

Thanks again.

Before I explain I want to go on-record that I don't think it is a good plan and I recommend you hire a lift to haul out and do this on land.

In answer to your question - It's important for several reasons:
1) Think about the geometry of the triangle formed between the forestay base, backstay bases, and the mast base, while the boat is unfolded. Imagine looking down from above the mast - the stays form a good angle from bow to mast base to backstay base.
Now fold the boat and think about how the angles change - from bow to back they now form a VERY wide angle, probably about 160-170 degrees (approaching a "critical" 180-degrees). If a strong wind blows, the halyard stretches a little or the boat rocks causing the beams flex upward; the result is that the masthead could momentarily swing beyond the 180-degree point and it would come crashing down.

2) When you fold the boat the geometry of the wings will push the amas downward so that they go deeper in the water and the center hull rises. All Dragonfly boats have this design feature. This increases form-stability so the boat is not as likely to roll despite it's narrow base. If there is only one ama attached, only one side will rise. The side without flotation will have no resistance and plunge down due to the unbalanced form (combined with top-heavy rig) causing the boat to roll over and capsize.

3) The weight of the remaining ama while unfolded causes a counterbalance effect similar to a proa. Folded, the remaining ama becomes a lever pushing the boat over with no counterbalancing effect.

I think you will have a very difficult task to try to "drop" one float while the boat is in the water, because the float will float (not drop on its own). Even if you are able to detach one end and not the other you may do even more damage to the remaining pivot while trying to finish the job because the loose float would be difficult to control. It would be impossible if the boat is folded and the floats are pushed even deeper.

[Steve B.]

I usually keep my boat at my dock unfolded, but I am currently waiting for a couple replacements for my new mats so it's folded.
The weather turned very cold and nasty with snow and ice, so even if I wanted to, I am unable to unfold the boat until the weather improves.

Recently, after all the above weather, we had a big windstorm with the wind causing the boat to heel significantly away from the dock.
Thankfully, I have a wide dock and was able to attach the the main halyard to a cleat across from the boat!
Now I can sleep peacefully when it blows hard until I receive my mats and the temperature melts all the ice and snow.

[Tuca]

Thanks again Double Horizon,

Really well explain and very clear.

I will do it following all your indications. I will ground the boat, anyway I need to re-do the antifouling before Spring.

It seem that over the metal frame there is soldered a U-Bar. The M20 Bolt is fixed with a few soldering points to this U-Bar. I will try to cut this soldering points to remove the bolt. In case that not possible I will remove the U-Bar.

Will keep informed and upload pictures.

[Tuca]

The bolt that join the ama with the aka is already removed.

The bolt was soldered in the underside to the U Bar and was also soldered in the top side as can see on the picture.

In the top side you need to remove the circular teflon part, is only fixed with 4 rivets. The top side soldering can be cut with a Dremel and a cutting disk with lot a patience without making big damage to the glass fiber.

The U Bar was cutted with a radial grinder from inside de ama. Not easy but do-able. You have to remove the GRP over the U-Bar to get access.

Metal frame is intact in the boat. I just need to solder the U bar and solder the top side of the new bolt.

I don't known how to post pictures. I put Goggle Drive links to the pictures.

https://drive.google.com/file/d/1J_Luur ... p=drivesdk

https://drive.google.com/file/d/1RJ9_qW ... p=drivesdk

https://drive.google.com/file/d/19NfN00 ... p=drivesdk

Mr. Jørn Olesen from Quarning have inform me that bolts nuts used are:

M20 X130 mm DIN 931 A4 Bolts/Screws

M20 NUT DIN 934 A4

M20 Waschers DIN 125 A4

DIN = Deutsche Industrie Norm (German Industrial Standard)

[Tuca]

What tightening torque must I give to the bolt/nut that join ama with aka?

[Steve B.]

I purchased my DF1000 (#15) used in 2000.
I adjusted the ama / aka nuts not with a torque setting, but to the point where there just started to be a very slight bind when folding, then I backed off just enough for the bind to disappear. No problems since.

[Tuca]

Thanks, will do that way.

Untill now I was applying some grease on the circular teflon plates. Have read on other tread in the forum that most people are using then without any grease. That teflon can work ok with just a good cleaning.