Attaching equipment inside hull

[suiramor]

I need to attach some small (+-10x20") wooden boards inside the hull: a board supporting the engine battery and another one to fix a transceiver to. The battery one can be attached to the cabin flooring on one side but there is nothing on the other. even the flooring is not that fixed - it is removable after all. How do I make these things fixed to the hull? I am loath to use screws and make holes in the fiberglass, even where it is a false bottom - there is additional bilge space underneath. Can I use glue/epoxy?

[George_SD]

Yes, using appropriate glue/epoxy will do the trick and I would also be hesitant to drill extra holes.

It would be best if you took a picture and marked spots where you want to mount something with some explanation. Then we can give you better ideas and suggestions. Epoxy can work, but some of them are not flexible and can be brittle. Using special glue/adhesive like 3M 5300 can be a good option. It's pretty much water proof, made for marine application, super strong (pain to remove, so make sure you use it for permanent stuff).

[stormalong]

Yes, you can use epoxy.

You need to glue the wood in place and then glass over it to make it strong. It has to be glued while someone or something holds it in place until the glue sets up. The glue only needs to hold the weight of the wood temporarily. Choose a very fast setting glue.

After the initial glue up you can glass over it to make it strong. It can be tabbed in place or completely covered with layers of glass cloth. The cloth should be at least an inch wide on the hull. Maybe more if the radio is heavy. Epoxy needs to stick to clean fiberglass, not a painted surface. The hull needs to be lightly ground to expose that clean fiberglass. Even if the hull is not painted it is essential that the surface be ground slightly. The curing process when the hull was laid up creates a waxy blush that would prevent the epoxy from sticking properly.

You are attaching a flat board to a rounded surface so fiberglassing over it is the best plan.

[suiramor]

I was planning to install my transceiver under the stern sb berth, attaching a flat board (blue drawing) to the canal (?) in the center of the boat and the opposite bottom.

I will look into the 3m 5300. Thanks!

[Rumrace]

The wood you use is important and plywood has proven to be the worst. The post on drilling holes is important advise. This allows resin to really connect to the wood and through it.
The next thing I’d consider in helicoils in the wood to mount hardware. This will keep the wood encapsulated and only an alloy Zinc or stainless. “ nutcert or helicoil “ once the timber is in place cover the nut top in a small rolled clay tube. I’d use Lexel to glue wood to fibreglass because it will allow the fibreglass to flex. Puddle in the corner a bead of Systems West with a good load of micro balloons. The same mix down all the holes you drilled in the wood. Pure resin does not connect as well with out the glass fibre. The micro balloons are little balls of fibre which chemically and mechanically connect the roving On each side l.
Engine mount you really need a navel architect to sign off. Diesels tend to pound their mounts to death. The engine mount must spread this pounding over a much larger area and tie into several stringers.
One member was telling us about Neptunis Yachts engine mounts flexing the whole hull on 2-3M boat. It’s not easy. The engine also needs a pan under it. My pan cradles engine battery and a small tool box. Behind it is the generator with a tray built in to it. An engine mount would have two long longitude boards and at least one connected across on a stringer. Roughly a T shape the forward boards towards the keel the top the Bank of the engine. Diesel engine mounts for any model I know of seem really over priced. As high as 10% the cost of the engine. If you have them on a solid footing.
The EPoxy glass roving in thin layers should be a touch over 1/8 of an inch. Add one layer or carbon Matt in between the glass layers. My boat has carbon Matt in a few key spots i recently learned

[Ballsnall]

Cot your boards to size and mark the position on the hull. I would recommend marine ply but that is very expensive and non marine ply will last decades if you paint it with thinned epoxy resin first. Sand the hull and attach with thickened epoxy, paint it and your done.

[GordMay]

Originally Posted by suiramor

I will look into the 3m 5300 '5200'. Thanks!

That would be 3M's '5200'.

[scherzoja]

Instead of using wood for the support structures, consider using fiberglass. You won't have to worry about delamination or rot (through the bolt holes). On a flat piece of table, cutting board, or even packing taped-cardboard, lay out 1 or 2 pieces of fiberglass (mat, cloth, 1708, etc...) in the rough shape as the vertical supports, then wet out with polyester resin. This will be the support that you glass to the hull. Once cured, cut to rough shape of the piece that you need, then glass that to the hull with epoxy and layer up 1708 to form an integrated, strong tab to support your devices/battery. The initial piece of fiberglass will be thin and is just a form for laying up additional fiberglass/epoxy to get to the thickness you want/need.

To keep the thin fiberglass piece in position, you can as small bit of hot glue and some small pieces of mat with a hot mix of polyester resin. Once that has gone off, grind off the rough spots and tacky film, wipe with acetone, then begin laying up 1708/epoxy to bond that piece to the hull. When the supports are ground smooth and to final shape, you can then attach cleats or whatever to hold your platform (another fiberglass sheet, epoxy/G10 cleats, or a piece of plywood for your shelf).

If you want this semi-removable, make the tab you glass to the hull as short as possible, then bolt the removable primary support through that. When you do this, you can assemble the removable vertical support and shelf, then lower it in place onto the fiberglass tabs, then drill holes. This way, you can get your shelf to be perfectly placed so it is level and there are no low corners.

I often will assemble everything, then lower it into place on the hull and glass to the hull. This ensures that all pieces are aligned. When doing this, I don't bolt the primary supports to the hull tabs, just use C clamps. Essentially, you install in reverse: Make the shelf, make the primary support, temporarily clamp to the hull tab, then place on hull in the exact position and lightly tab with hot glue or small pieces of mat with hot mix of polyester resin. Once poly has cured, carefully remove all pieces and permanently glass the tabs to the hull. Remember to add some cardboard or whatever as a shim between the hull tab and the primary support to give space for the layers of fiberglass/epoxy you will use to secure the tab to the hull; otherwise you alignment will be off by that thickness. Use clear packing tape as a "release agent" on surfaces that will come into contact with epoxy that you don't want to glue.

The attached drawing is just a rough illustration of this modular concept. Adjust the dimensions to fit your load.

[goboatingnow]

For what you want 5200 and ply will make a fine base give it a coat of paint

[David Mathis]

About ten year ago the air horns were moved from the deck next to the sunpad (See the problem? Poor planning at the factory.) to the anchor pulpit. This required moving the two compressors to the rode locker. A piece of 1x6" pine about a foot long had the corners tapered to properly fit the curve of the hull then the edges where they contacted the hull were coated with 5200 and taped in place to set. About a week later (5200 takes a long time to set) the compressors were mounted. They haven't moved.

[bcboomer]

Weld Mount Adhesive Systems have a variety of studs and fasteners that can be attached directly to the hull.
I mounted the hot water tank to the hull with 4 of their studs. Just be sure to remove any hull paint first.

[coopec43]

I agree with scherzoja's approach. I wouldn't use wood nor would I use epoxy. Polyester resin over a f/g channel (?) section would be fine.


When I made provision for the Auto steering ram I roughed up a square meter on the inside of the hull then laid CSM/Polyester resin. I then f/glassed the ss mounting points in using polyester resin.


https://www.lbifiberglass.com/which-...vs-vinylester/

[RSB333]

I built a battery box of Marine Plywood and supported one side with a wedge of solid mahogany. Affixed it to the inside of the hull with 3M 5200 five years ago and it's never showed any signs of letting go.