Steel Hull 45 ft New Deck

[PigZen]

Hi
I need to re-deck this 45 ft steel hull work boat. It is a 1986, Phil Bolger design with a 30 HP SABB engine. It has a steel hull with fore and aft watertight compartments. Th deck is 3/4 inch ply with a thin layer of FG and is rotting. The deck extends under the wheel house but I expect I would want to remove the wheel house and replace the deck there as well. Hull is in very good condition and shows light pitting in a few places. The mast is keel stepped on a steel pedestal. I am considering replacing the deck with steel. Tight budget. Expect to do most of the labor myself. Have carpentry skills but no welding experience. Am a fast learner though. The boat needs to be able to make the crossing from Cuba to Yucatan when complete. Advice appreciated.

[David M]

I would replace the deck with steel and hire a professional welder with experience with steel boats. The welder's job would be to cut and weld but also to teach you how to weld. You are also going to need the advice and plans from a naval architect so that you have a sound design.

[Cormorant]

Just curious -- which Bolger design is it?

[Cheechako]

Yeah, a steel deck wouldnt need to be too thick really, assuming there are supports under the ply deck. Ply and glass is almost always a bad idea. Hire a welder to get you going, learn to cut and fit the plates if you want to save money. Dry fit it all using his advice, then pay him to do the welding. Welding steel like that can result in a lot of oil canning and shrinkage, you need an expert to help you.
It's hard to visualize what you have going on there though, especially where deck meets toerail and cabin etc.. Maybe an alternative is purchased fiberglass sheets. How was the ply sealed to the hull /toerail/bulwark area etc?

[PigZen]

I don't know which Bolger design it is - I looked for it on the wiki page and couldn't find it.

I will contact a few welders locally and get some bids. I like the idea of the guy teaching me to do the job while we does the plans and lays out the sheets. The ply is bolted through a steel lip which runs around the interior of the hull. Bots every 3.5 inches approx. the deck does have a camber looks like of about 4-5 inches and there is minimal support underneath, only some 2" wooden arches, there's two columns and a header underneath the front wall of the wheel house.

[PigZen]

some links to pics since I can't figure out how to post them here:
https://drive.google.com/open?id=0B8...3doTWtYYTBMSk0

https://drive.google.com/open?id=0B8...DY0aTNCMVhqdk0

https://drive.google.com/open?id=0B8...ExXNnRJOTVaRm8

https://drive.google.com/open?id=0B8...lZDdUJaSkNmd3M

[Dody]

As nice and interesting it might be to learn welding at this point, please keep in mind that you have to remove ALL your interior before you are starting with the job which is a huge amount of additional work. I just had the case with my neighbour who was of the opinion he would manage without doing this. They were only tackwelding the sheets in place to do the complete welding this week. Even though someone was inside watching to prevent it, last Friday at 14:15 they had set the boat on fire, black smoke was coming out of the hatches and then big flames came licking out. We tried with buckets and water-hoses while hoping the fire-brigade would arrive soon. In the end they managed to put out the fire, no-one got injured, but it was very close that he would have burnt the whole place down including my boat. Inside everything is burned now, everything plastic melted away, black and a big mess.

I am replacing my plywood-deck next door. Although I did remove my interior for other reasons you can replace a plywood-deck with the interior still in place.

Good luck & fair winds
Dody

[Dody]

Originally Posted by PigZen

... I will contact a few welders locally and get some bids. I like the idea of the guy teaching me to do the job while we does the plans and lays out the sheets. The ply is bolted through a steel lip which runs around the interior of the hull. Bots every 3.5 inches approx. the deck does have a camber looks like of about 4-5 inches and there is minimal support underneath, only some 2" wooden arches, there's two columns and a header underneath the front wall of the wheel house.

You won't be able to weld the the new steel-deck to the deckbeams (the wooden arches you are talking about) as they are wood, the plywood would have been screwed or nailed to the deckbeams. Which means you will also have to replace your deckbeams with steel-ones.

If it was me I would stick with plywood, far less work. You could sheet it with fibreglass and epoxy which means you'll get a good bond as opposed to polyester.

Fair winds
Dody

[Captsteve53]

Dody's got a good point , especially if you have wood experience and only use Epoxy coatings/glue etc,

My self I'm a steel guy been building in steel and alloy for more than 30 years so thats my choice, but you would need to place steel deck beams across the hull at every frame location (some thing like 50 mm x 6 mm or 40 mm x 10 mm) what ever they need to match the frame size as rule of thumb, these can be bent in a simple home made hyd jack arrangement to get your deck camber,

The decking plate needs to be 3 mm min but can be up to 5 mm max, 3 mm takes a bit of welding not to end up with an unfair deck, so welding technique's such as back step welding/stitch welding/stagger welding needs to be employed staying away from the temptation of doing uninterrupted long welds.

All the steel should be shot blasted and primed with a weld through primer prior to installation then a daily clean up and prime as you go,

So after that the plywood bay not be a bad idea!

Cheers Steve

[Scaramanga F25]

Plywood, cloth and epoxy.

[foufou]

Have you considered foam core? Lighter weight, better insulation and no chance of rot. Coosa board or equivalent glassed on bottom only sl you can achieve camber easily, then top class done in place. Just need to figure out lamination schedule for spans involved. Naval architect could help with laminate needed. Or build some test panels to jump on

[foufou]

Have you considered foam core? Lighter weight, better insulation and no chance of rot. Coosa board or equivalent glassed on bottom only so you can achieve camber easily, then top glass done in place. Just need to figure out lamination schedule for spans involved. Naval architect could help with laminate needed. Or build some test panels to jump on

[Dody]

Originally Posted by foufou

Have you considered foam core? Lighter weight, better insulation and no chance of rot. Coosa board or equivalent glassed on bottom only so you can achieve camber easily, then top glass done in place. Just need to figure out lamination schedule for spans involved. Naval architect could help with laminate needed. Or build some test panels to jump on

The OP is looking for a solution that doesn't hurt his purse too much. Core is a lot more expensive than plywood, and, as long as he copies what is there he has no need for the additional costs of a naval architect. This deck was doing it's work for 31 years and was fine. Why re-invent the wheel if money is an issue?

[Dody]

Edit to my post: Steel is cheap too, the difference is the additional work involved in removing his interior - and later getting it back in again. Plus the fact that he can do woodwork himself, but has no experience with steel-work and welding yet, so needs to hire (and pay) someone.

And there might be another thing to consider: where is the boat now? The OP was talking about the boat has to be able to make the trip from Cuba to Yucatan. Is the boat in Cuba now? If so, he shouldn't have problems to dig out plywood, Epoxy and Fibreglass as well as steel somewhere. Everything else might be a bit of a challenge.

[Pauls]

Yes, you can replace with steel. A steel deck is far better than a wood one one a steel hull. The deck is a structural part of the hull and has large stresses applied to it. Wood bolted to steel inevitably shifts under the strain, leaks, and rots.

Depending on how heavily your boat is built, you will want to use either.120 thick plate (11 gauge) or .134 (10 gauge). You will need to fab deck beams from steel, they should be 1/4" thick and from 2.5 to 3" deep, again depending on your boats displacement. The longer beams should have caps, about 1/4 x 2 1/2. Very important, you will want to run longitudinals spaced no more than 18" apart, they should be 3/16 x 1 1/2. The longitudinals are what will keep your deck free from warpage.

Make patterns from door skins or cheap 1/4" plywood. Transfer those to your plate for cutting.

Clamp the deck plates in place. Tack weld the deck plate to the longitudinals first, then weld the longs to the beams, then weld the deck edges. MAKE NO WELD LONGER THAN 4". This means make a less than 4" weld, then move to another location, make another weld, move and weld, etc. This is how you make a distortion free deck. The welding is not difficult, you should be able to pick it up quickly enough to be able to do a decent part of the job if you are trying to save money.