fiberglass radar arch

[mjkkemper]

just wondering if anyone has built a fiberglass radar arch? If so any pic's

[rasorinc]

Here is a pic of one I'm ging to replicate. It is out of wood but a nice design.
Did not come thru will try again. http://www.glen-l.com/ go to customer photos. Click on Bear Cat by Andy Smith boatworks.

[CDK]

Do you mean something like this?

[mjkkemper]

Originally Posted by CDK

Do you mean something like this?

yes


i wanted to see how other people made their plugs or how they did their layup

[CDK]

There never was a plug.

I made the mold from heavy impregnated plywood, lots of plaster and some silicone. Because I knew that the mold would not survive the operation I paid little attention to prepare the surface: just a single coat of PVA. After the gel coat and three glass layers I embedded stainless tubes in the edges and some pieces of wood to support the upholstery, followed by one last glass layer.

The shape is such that the mold has to be broken over the whole length of one edge to release the object.

[Pat Ross]

How do you insure the strength to mount a traveler and main sheet?

[gonzo]

That's a totally different thing. You will have to start by calculating the structure on the deck where the arch will be mounted to.

[mjkkemper]

Originally Posted by Pat Ross

How do you insure the strength to mount a traveler and main sheet?

For a Radar arch I was planning on installing the radar on it

[mjkkemper]

Ended up making one and installed it today.

[iceboater]

Originally Posted by mjkkemper

yes


i wanted to see how other people made their plugs or how they did their layup

Thanks for sharing. Could you share with us how you made yours, plug, layup, material?

Axel

[CDK]

Congratulations mjkkemper, that's looking good.

Probably you'll need to modify the way it is attached to the flybridge, with two contact surfaces instead of one on each side. You won't like the way it swings back and forth on a rough sea.

[mjkkemper]

Originally Posted by CDK

Congratulations mjkkemper, that's looking good.

Probably you'll need to modify the way it is attached to the flybridge, with two contact surfaces instead of one on each side. You won't like the way it swings back and forth on a rough sea.

When the aft hard top is added it will avoid this


Below is the plug


Lay up - veil, chop mat and 3 layer of 1708 bi-axle


Wire chase and closing up the inside


De-miles and 3# urathan closed cell added in the chase


Flaring out the inside


Touch up

[tunnels]

All archs have 4 weak points !the two top 90 degree corners and the two mounts where they are fixed down . Depending on what gets loaded on top and how much weight is there will determin the amout of movement and the forces involved so just be aware !! One line of production boats always had trouble in those 4 places till they changed the design signifcantly .

[mjkkemper]

Originally Posted by tunnels

All archs have 4 weak points !the two top 90 degree corners and the two mounts where they are fixed down . Depending on what gets loaded on top and how much weight is there will determin the amout of movement and the forces involved so just be aware !! One line of production boats always had trouble in those 4 places till they changed the design signifcantly .

Very interesting and makes good sense. Below is how it's tied inside. 45 degree for lateral support.


The hard top will be about half way up the arch and I would think it would help with the two top 90 degree. Splashing tue so we will see.

Interesting on the new designs. What did they change or improve?

[tunnels]

The upper 90 was broken into 45 and bigger and thicker inside was a pre moulded very stiff glass moulding all on edge completely round the corner , part way along the top and part way down the sides . The bottom one side became a part of a seat back and so tied the whole thing much better !! always vibration but nothing lke it had been !