narai mkiv beam bracket replacement

[dan]

I recently purchased a narai MKIV from the seventies. I have found that the brackets holding the beams in place are old steel and rotted out and I need to pull up all the beams and replace the steel brackets. I was wondering if anybody has any experience with the trough style design theme
and could tell me if it would be better putting aluminum brackets in next time or to continue to go with the steel. I also have to remove the wood decking the masts and all the rigging. I have a center engine pod design and I'm going to have to support the engine pod while I'm taking out the two center beams but I don't know if there's any way for me to do this other than on the hard. if anybody has ever replaced these brackets and has any insight on an easier way or better materials as they're nearly unserviceable in their position once everything is installed, I would love to hear your experiences replacing these. thank you

[Penn D]

It would be cheaper to build them than post them. .. specially since they would probably need modification; )

[Don Brazier]

Brandon Gamble said:

Interesting Ideas here... Not a solution to your problem but I'll come by on Monday to help with that.

Hi Brandon

Yes some interesting ideas on the site you indicated

I used a somewhat similar system when I modified my Narai IV Katipo 

Beams one and four were lashed down to large eye bolts with heavy square washers and plenty of sealer, and  using horizontal frappings as can be seen on this page  http://wharram.com/site/wharram-world/voyages/katipo-voyage-part3

Hardwood pads on the tops of the beams overlapped giving  vertical lashings 

Beams two and three were moved out slightly with hardwood pads against the side of the beam trough.  This gave room to lash Tiki style at the outer beam ends through holes in the hull sides

see         wharram.com/site/gallery/classic-designs/narai-mkiv

the beams were just long enough

the inner ends were also  lashed Tiki style. Further reinforcing was made inside the hull , as was the case for the outer beam ends of these two beams.

 

I suppose it may be simpler in many ways  Dan to copy and replace what you already have but with the old bolts shearing off and getting in the way, and with  new brackets with the potential to rust later , it is probably worth considering all options

Don

[dan]

This is great! Love the ibolt idea with lashings. Did u upgrade the bolt thickness? I'd really appreciate a couple photos if u got em of beams 2 and 3. I'm trying to find ways to keep my beams for now and this is creative and useful idea for the bolt down beams

Don Brazier said:

Brandon Gamble said:

Interesting Ideas here... Not a solution to your problem but I'll come by on Monday to help with that.

Hi Brandon

Yes some interesting ideas on the site you indicated

I used a somewhat similar system when I modified my Narai IV Katipo 

Beams one and four were lashed down to large eye bolts with heavy square washers and plenty of sealer, and  using horizontal frappings as can be seen on this page  http://wharram.com/site/wharram-world/voyages/katipo-voyage-part3

Hardwood pads on the tops of the beams overlapped giving  vertical lashings 

Beams two and three were moved out slightly with hardwood pads against the side of the beam trough.  This gave room to lash Tiki style at the outer beam ends through holes in the hull sides

see         wharram.com/site/gallery/classic-designs/narai-mkiv

the beams were just long enough

the inner ends were also  lashed Tiki style. Further reinforcing was made inside the hull , as was the case for the outer beam ends of these two beams.

 

I suppose it may be simpler in many ways  Dan to copy and replace what you already have but with the old bolts shearing off and getting in the way, and with  new brackets with the potential to rust later , it is probably worth considering all options

Don

[Don Brazier]

Hi Dan
Here is some more information which you requested. Photo one is Beam two with beam cover on , photo two Has beam cover off showing lashings . The beam sits on 12 mm conveyor belt rubber on the flat bottom of the beam trough.
The centre horizontal beam bolt passes through a small vertical slot in a hardwood block glued to the beam trough side.
There is no slot in the beam as is the case with the larger Tiki designs, only a round hole for the bolt.
There does not seem to be any appreciable movement here.

Photo three is an example of the eye bolts to which beams one and four were lashed.
It is a 16 mm chain link welded to a 16mm rod with a plate welded on , so as to be able to seal underneath it as it passes through the base of the beam trough ( like the bolts do that you currently have with your rubber block Wharram design system ).
The galvanising did not seem to last well so I changed to 16 mm threaded stainless rod with stainless eye nuts, and a large square stainless washer underneath the eye nut.
You have to bear in mind that details of this system have not been sent to Wharram for approval and I realized use of stainless may be doubted by some. Also the fact that lashing lengths on beams one and four are different to beams two and three , and could be allowing unequal 'give' on lashings ?
But from reports in this forum it is evident that some lashings take more load than others anyway, especially the inner lashings on beams three and four .
However, I have sailed for over 8000 miles so far with this system on a couple of Pacific voyages and have had no problems to date. It may give you some ideas for approaching your situation.
Don

[Don Brazier]

Sorry I had a glitch with the photos. Here is an example of the welded eye bolts which were fine except that the galvanising did not last well. I then changed to the stainless system as described
Don

[Don Brazier]

And here is the beam two photo which did not come through before which , like Beam three, is lashed down Tiki style
Don

[Adam Shuttleworth]

Hi Matt. I'm in W.A. Any chance of some pics of these brackets with some measurements. I'm about to embark on the same job as Dan

matt connolly said:

If your on the east coast of australia i may have a full set of new steel brackets that you may be able to use. They were for a tangaroa mk 4 but i dont need them.

[Adam Shuttleworth]

Hey Dan, How's the progress of this going? I'm embarking on the same job in September and I'm unsure which way to go with it

[matt connolly]

Hey Adam,l still have them here though they may need sand blasting and re painting. l'll get some photos happening. And measurements,though they are for a tangaroa and l'm not sure if they would suit a narai. They were made from my plans though,so as described by wharram.

[dan]

Progress is going well. Slow but well. I opted for doing the stainless steel brackets on the outside only but upped the thickness to 3/16" and uppedthe lag bolts to 1/4" changed the bolt pattern also to go into fresh wood. I am putting beam lashings on the inner beams. Since I can I will upgrade to more flex as the inner have more flex naturally anyhow. This has been a tricky task as I cannot remove the beams at the dock. Good luck. I can figure out how to post pics and show you my ideas.

[matt connolly]

Here's the said photos of a couple of the brackets. They were sand blasted then painted in 2 pack,but there are a few rust spots here and there.

[Adam Shuttleworth]

Thanks for that. They're very different to my set up. I'll get a few pics in the coming weeks when I'm back on the boat and post them up. I'm delaying the Overhaul now until April next year.

matt connolly said:

Here's the said photos of a couple of the brackets. They were sand blasted then painted in 2 pack,but there are a few rust spots here and there.