Mizzen tabernacle

[Sue Pagan]

Looking for some thoughts about my cracked tabernacle.....

No idea what the cause was, but there is a separation of the tabernacle on the front and port edge and a crack underneath the cleat on the post side .

I think it must have been caused by a pretty substantial twisting motion and  it was assessed as needing repaired  before it deteriorates, by the surveyor last September 

My thoughts are to glue and clamp it and place  a fabricated stainless steel 'horseshoe' band round the front and sides, above the upper ring on the front face and the cleat on the port side of the tabernacle; and another one  below the cleat on the port and between the two rings (very roughly marked in the pic.

Any advice, ideas gratefully received

Best wishes,

Sue

[Graham Matthews]

We did exactly that on Dougal. Substantial stainless straps through bolted to a plate on the bulkhead in aft cabin. 

Be warned that when we did this we discovered that the bulkhead was seriously rotted and needed a large section replaced at the same time.

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[Brian Jones]

Hi Sue,

Further to my last. I still think you should remove the trunking from the bulkhead as I suggested via removing the nuts in the aft cabin. If the 1/2" ply in the aft cabin is rotten that should be replaced and the bolt holes through the thin fibreglass bulkhead should be drilled through the 1/2 inch ply. The ply is bonded to the fibreglass with something like Sikaflex. When you have the trunking off you may find that it's split elsewhere. This box section takes a lot of weight as I stated previously and the rain water running down the track of the mast finds its way down the inside of that trunking despite the angled covering plate, that is why you should not use stainless bolts when replacing it.  I think you would be well advised to take the trunking to a carpenter who may be able to scarf a new section in the top portion and screw it together. Teak can be glued but to do so successfully you have to warm the joint and soak it in turps and when bone dry repeat the process. That draws the oil out of the wood and then it can be glued but a carpenter worth his salt would know that.

You can't take short cuts with something like that trunking or the decking around the base of the mainmast. That mizzen mast trunking sits on the moulding around the engine hatch and that is what takes the weight. The bolts through into the aft cabin hold it against the bulkhead and that's all. That bulkhead is the thinnest in the boat and was not made to take any weight. Putting stainless straps around the trunking may look very good but you're not adding any strength apart from holding it against the bulkhead, which is itself weak.

I hoped that explains what I previously said.

I belong to a Radio controlled scale model sailing yacht club and one of our members is making a scale model of Rouselle, my old Seadog MK IV.  Now owned by Alexia Jenkins.  At the design stage the hull is something like 42 inches long and 13 inches max beam. All scale models sail exactly like a real one and one of our members who had no idea of sailing, can now successfully sail a

Shelduck which in real terms is I believe about 24ft long.

Have fun,

Brian

On Monday, March 20, 2023 at 10:37:52 PM GMT, Brian Jones <brianbr...@yahoo.com> wrote:

Hi Sue,

Personally I would not rely on gluing the trunking because of the oil in Teak. I would remove the whole thing from the bulkhead. It's secured by four long bolts the nuts of which are under a short covering teak pads on the aft bulkhead near the the hatch entrance. these bolts should be renewed every fifteen years anyway. When you have got it off have it remade in African Teak if you cant find any Burmese Teak and refit it with new galvanised bolts. Don't use stainless as there is a lot of water gets down the inside of that trunking and stainless bolts in damp wood will rot quicker than galvanised.

That trunking holds the weight of the mizzen mast including the downforce of the rigging and sail, plus the weight of the randome if radar is fitted. It is also where the hot air from the engine exits.

The aft bulkhead is only thin fibreglass which has 1/2" marine ply ply bonded to it on the inside. Sometimes this plywood is rotten around the hatch which is a clear indication that the bolts need renewing as they may have rusted right through.

Kind regards

Brian

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[Brian Jones]

Hi Sue,

Thanks for yours. It may seem a lot of work to start with but once the mast is off and the bolts are out the rest is plain sailing. The trunking will come off in your hands. If you have a radio aerial on the mast you will need to remove it from the rear of the VHF and pull it through. Don't forget to replace it afterwards.  Once the trunking is sorted you can forget about and it should not cause a problem again. If you get stuck with anything come back to me.

Kind regards

Brian

On Sunday, March 26, 2023 at 05:16:00 PM GMT+1, Sue F Pagan <suef...@gmail.com> wrote:

Hello again Brian,

Excellent advice as ever.  Thank you.

Kind regards,

Sue

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