Got an Aluminium Hull, What Next?

[squirrel]

Well hello everyone! After long months of hard graft and saving i finally got the hull delivered to my local boat yard. I've done my research in the meantime and have the layout n rig figured out. Im going to use spray foam insulation, however im a little confused as to what i have to do before putting the insulation in. Apart from putting in the bulkheads and installing the mast step (id like to go for a junk rig so will need a keel stepped mast but wont need most of the running rigging), what else needs to go in before the foam?

As i said iv done my research and have decided on most of the things, but i cant seem to find much info about the order that they all get installed. Can anyone point me in the direction of any literature that discusses fitting out bare metal hulls? Or if it would be easier give me a short list of things i gotta do in a consecutive order thanks!

[estarzinger]

Originally Posted by squirrel

give me a short list of things i gotta do in a consecutive order

I did this 12 years ago. Have fun!

Before spraying foam you want to:
1. do all the deck welding you are going to do - so any cleats, tapped plates for blocks and winches and jib tracks, etc. And any inside hull side welding - I have aluminum tangs which my main bulkheads and sole are bolted to.

2. Bolt onto the frames whatever material you are going to use as the base for screwing the ceilings and furniture in place. Most people use epoxy coated wood ("furring strips') although there is a good argument for using a plastic (like starboard). You do NOT want to screw stuff directly into the aluminum - if you do the screws will drip condensation and cause corrosion and freeze in place.

3. Put in your wiring conduit - however you plan to do that, with messengers installed thru the conduit.

4. There is a debate whether it is better to put the sole and main bulkheads in before or after foaming. I did it before - to 'seal' their edges in place.

You want to install the wiring and plumbing after the foaming. Try very hard to make the foam surface as flat and smooth and level as possible - that will save a lot of work later.

[atoll]

may want to put your wood battening to fix your plywood hull panelling to first,if spraying foam to the depth of the stringers.

also tape off and cover with plastic any areas you do not want foam on,stuff makes a hell of a mess and is hard to get off ;drips/overspray.

you can etch prime bare metal as this provides a barrier against possable corriosion and provides better adhesion.

also make sure there is good ventilation when spraying and fire extinguishers handy

might want to lookon this site for tips

Welcome to the Metal Boat Society

[squirrel]

Cheers guys! Ive uploaded a photo of what she looks like on the inside. Think most of the inside welding been done at the factory... Estarzinger regarding your second point, if i shouldnt use screws whats a good alternative? Aluminium rivets? Sleeves? Or glue?
Atol not sure if im going to trust myself to do the spraying as iv never attempted anything similar before, n as we all know the first pancake is always lumpy... And i do want to save myself some work... But priming is certainly on the list, and now so is taping and covering. The site looks helpful too, thanks!

[estarzinger]

Originally Posted by squirrel

if i shouldnt use screws whats a good alternative? Aluminium rivets? Sleeves? Or glue?

actually I was making a slightly different point - same as Atoll's "wood battening to fix your plywood hull panelling" - most metal boats have wood battens (furring strips) bolted to the frames and then the ceilings are screwed into that wood - that makes these screws later removable and since they are not in contact with the hull they do not drip condensation.

As to the battens/furring - two things - first as I said previously, they are usually epoxy coated wood but there is reason to consider a plastic like starboard (which will not potentially hold moisture against the aluminum like wood might - although the epoxy coating should prevent that). Second, most people use stainless bolts for attaching these to the frames but I used 5083 aluminum bolts - hard to find - not sure it makes much difference but I tried to avoid dissimilar metals everywhere I could.

I found this part - figuring out how to attach the ceilings - to be the only moderately tricky part of the boat build - everything else went in a straightforward manner.

[GordMay]

See ➥ Motoryach Headliner Installation - The most usual finish is Vinyl or Polyeutethane upholstery fabric over foam padding; but any laminate could be glued over the door skin panels. Cruisers & Sailing Photo Gallery

[atoll]

as fasteners i used galvanised chip board posidrive screws,3.5mm through 4.2mm holes in the alloy stringers into pine battons.

i have just removed headliners after 12 years and no corrosion between alloy and screw,except where the screw was tapped direct into alloy,and the corrosion in most cases is on the steel screw rather than in the alu.

there is a very simmilar potential difference between galv mild steel and alu hence little corrosion.

where as between stainless and alloy in direct contact have found a large amount of corrosion where nylon washers were not used.

would reccomend using a composite as batons ie;pvc box section or L section with a wall thickness of 4-5 mm.

pine is okay but can rot in damp spots,meranti wood epoxy coated would work better.

will post some photos if i get down to the boat today.

[atoll]

i had a look at your photos one thing that jumps out is your bilge keel attatchment!

also the keels,would really reccomend getting them galvanised.

also the keel bolt plates,would use bigger(10x10 cm) and get them galvanised.

you need to spread the load sorry dont mean to be negative but i had the skeg crack 10mm plate on our yacht exactly for the same reason.

easy to fix now,but very expensive to do it later,

[atoll]

refitt,battons and insulation exposed