New to the board: 78 sea nymph unanticipated restoration

[78sharpshooter]

Picked up a 78 sea nymph 17" and turns out the deck was rotted and the transom had termites. Some owner glassed all over the transom and deck (also they put awl grip over the deck and sides) and I spent the whole day ripping these out. Going for the rebuild I will be making a center console for it. What rivets should I use to attach 2 of the crossmembers that were riveted to the C channel on the hull? I have a AC TIG welder and am okay at aluminum so I wondered if this boat was made with 6061. Is there anything I can add to improve any structural feature of the boat before putting in the new deck and transom? Pics are below;

 

[bonz_d]

Re: New to the board: 78 sea nymph unanticipated restoration

Welcome to the forum! Loos like a nice project that shouldn't be too difficult to complete and should mae a nice fishing platform. I would thin that aluminum pop rivets should work. Are you going to add foam under the deck before you replace it?

 

[Bob_VT]

Re: New to the board: 78 sea nymph unanticipated restoration

Welcome to iboats.

Check out this section for a good primer for your project http://forums.iboats.com/showthread.php?t=288451

If you are good with a welder...... have fun. The aluminum takes well to welding but it is thin so be careful

 

[78sharpshooter]

Re: New to the board: 78 sea nymph unanticipated restoration

The old foam is a little waterlogged but intact so I am thinking of letting it dry, then sealing it with epoxy and putting it back in.


I am definitely going to weld the top plate to the upright cross member but am not sure about the upright to the C channel that is on the bottom.

Is it common to epoxy and glass the top and underside of the new deck prior to installing? I was suprised that the underside of the original deck was bare.

 

[bonz_d]

Re: New to the board: 78 sea nymph unanticipated restoration

If the foam is soaked sorry to say this but it will not dryout. It's pretty much ruined.
On this forum you will find most everyone seals the decking with epoxy on both sides, will last almost forever. My Lund was the same as yours as it appears to have been only varnished on both sides, saves the manf. money. Anyways, I went againt the crowd and did the same as original to save money and weight. The original lasted 25 years and I know the last few years it wasn't very well protected. Meaning left out in the wheather uncovered. But the choice is still yours. Also when replacing the decking you will find it is not reccommended to use pressure treated plywood in aluminum boats. Chemical reaction between the two!

 

[78sharpshooter]

Re: New to the board: 78 sea nymph unanticipated restoration

Thanks for the info on the foam. So what is reccomemded for the foam replacement? Is it the 2 part polyurethane foam? I am a little concerned about using uncoated foam because there does not seem to be a route for the water to drain back from the bow to the bilge.

I got pricing on marine grade 3/4" ply at ~$64 per panel and 1/2" at $56. Is it worth saving $100-$200 on plywood by going with the ABX instead of marine grade? I will still use marine grade for the transom though and do 1 layer of 4 or 6 oz Eglass over it.

 

[bonz_d]

Re: New to the board: 78 sea nymph unanticipated restoration

Many of the folks here are using the pink or blue foam board from any of the home repair stores and have found it works quite well and is much less expsensive. As for the plywood, you should do a search here on iboats for plywood and you will find more threads than you will care to read. There was one just a couple weeks back that was very informative. Wish I had a link to it for you.

Can you determine what thickness ply was originally used? I believe my Lund used 5/8" which is what I reinstalled and it is very sturdy.

 

[ezmobee]

Re: New to the board: 78 sea nymph unanticipated restoration

Most of us are replacing the foam with the pink or blue construction sheet foam from Lowes/Home Depot. Or pool noodles. I'm not a big fan of pourable foam in aluminum hulls. Marine grade is certainly a superior product but only you can decide if it's worth it or not. A number of us are fans of the Arauco ply from Lowes.

 

[bonz_d]

Re: New to the board: 78 sea nymph unanticipated restoration

ezmobee, do you recall the thread a couple weeks back about plywood? I recall it compared all three with pros and cons.

 

[mark1961]

Re: New to the board: 78 sea nymph unanticipated restoration

I am a little concerned about using uncoated foam because there does not seem to be a route for the water to drain back from the bow to the bilge.

Are you sure there are no small limber holes under each rib along the keel? They may be blocked up with debris.....

 

[78sharpshooter]

Re: New to the board: 78 sea nymph unanticipated restoration

I found several UPC labels on the underside of the deck plywood and it is BC plywood 23/32" so the original deck was not even exterior grade, right? (it was fastened with what looked like factory pop rivets). I was thinking of going 5/8" because I will be glassing the top and bottom of the deck panels for sealing, strength and durability (also because I have a lot of fiberglass left over from making a coupld stand up paddleboards and 3 gallons of epoxy that should be used sooner rather than later). Not sure if the transom was the same plywood but I am going with marine grade on that and then scarf joint the leftovers to make the bow casting deck. I will stop by lowes to check out the Arauco ply. I think I need 3 sheets for the deck and 1 sheet of 3/4 and 1 of 1/2" for the transom (the 1/2" leftover will be used to make new sliding doors at the stern area).

I haven't cleaned the keel/rib junction to see if there are holes there but I am hoping they are there. Where was the fuel tank located on these boats? For routing the wiring from the console to the stern, does anyone have suggestions on how to make this clean (under the deck)?

 

[bonz_d]

Re: New to the board: 78 sea nymph unanticipated restoration

For routing the wiring from the console to the stern, does anyone have suggestions on how to make this clean (under the deck)?

Sealtite. should keep the water out and allow you to pull wire as needed.

 

[Cadwelder]

Re: New to the board: 78 sea nymph unanticipated restoration

Sealtite is an electrical term for weather proof flexible conduit and its tuff to pull through, just use PVC conduit under your deck easy to pull through and cheap....

No offense bonz_d, I'm an electrician by trade....

 

[78sharpshooter]

Re: New to the board: 78 sea nymph unanticipated restoration

I presume that you could use a holesaw on the solid upright/vertical support to create the path for the conduit?

Is there an alternative method to attaching the deck besides pop rivets?

 

[bonz_d]

Re: New to the board: 78 sea nymph unanticipated restoration

Well let's 1st go back to your original post. The last picture, those 2 vertical supports are called bulkheads as they are 90deg. to the keel. Next question is that piece in the bow that is lose and looks like C channel, does that run down the keel and is being used as part of the floor/deck support?

Sure you could holesaw the bulkhead to run the conduit and looks like it would also assit in draining water back to the stern. When I redid mine I refastened it with SS flathead sheetmetal screws. I marked off where all mounting points were and screwed it down about every 8". That worked well for me.

 

[78sharpshooter]

Re: New to the board: 78 sea nymph unanticipated restoration

The C channel was from the transom. The bulkheads were originally fastened with pop rivets but 2 or 3 bulkheads came loose so I bought some high strength all aluminum rivets from mcmaster to reattach them. Did you predrill holes in the deck and/or bulkhead before inserting the sheetmetal screws?

 

[bonz_d]

Re: New to the board: 78 sea nymph unanticipated restoration

Yes I did predrill, marked the hull and drew a scribe line on the decking to mark the bulkheads. Drilled pilot holes then countersunk them as I did not epoxy my deck. Instead put down 5 coats spar varnish and then the waterproof carpet glue.