Steel hull Boat Interiors.

[SailingValkry]

Thank you all for the invaluable information! We are reading through all the information that you provided us, and looking into the books and professionals!

[reed1v]

Originally Posted by ausnp84

As above, as long as the hull has been protected properly with a good paint system, you should be ok for years. Keep the boat dry, air it out when you can, and fix any deck leaks. Stay away from teak decks as well - teak decks plus steel hulls are a recipe for trouble.

As for spray on foam, it's good but not infallible, and does break down over time. My boat had 300 black rubbish bags full of the stuff that was soaked through, and all had to be removed before we could grit blast in & out, and repaint the steel hull.

n

If its soggy, its open cell foam. Closed cell foam should not absorb any moisture. If the steel is painted with epoxy and then closed cell foam, should last virtually forever. The foam is needed to prevent condensation, especially below the water line where cold water meets warm air in the hull. Someone said not to foam below the waterline. Tell that to the US Navy. Works on their subs, will work for you.

[Rustic Charm]

Originally Posted by reed1v

If its soggy, its open cell foam. Closed cell foam should not absorb any moisture. If the steel is painted with epoxy and then closed cell foam, should last virtually forever. The foam is needed to prevent condensation, especially below the water line where cold water meets warm air in the hull. Someone said not to foam below the waterline. Tell that to the US Navy. Works on their subs, will work for you.

Mine doesnt have any foam below the water line and ive not had any problem with condensation below the water line.

When i was doing up the inside under deck two years ago i had six months without any foam, including one side above the water line and condensation was like rain on some days. But not since i installed the foam.

Someone suggested 'batts' bad idea if they get wet.

[Cruisingscotts]

Originally Posted by reed1v

If its soggy, its open cell foam. Closed cell foam should not absorb any moisture. If the steel is painted with epoxy and then closed cell foam, should last virtually forever. The foam is needed to prevent condensation, especially below the water line where cold water meets warm air in the hull. Someone said not to foam below the waterline. Tell that to the US Navy. Works on their subs, will work for you.

Having the pleasure of removing lots of foam from bulkheads, the above is true as long as the foam stays adheared to the hull. Shooting the cargo hold on a ship makes sense. Problem is the foam and steel will not move the same, any penetration into the foam, thru-hulls tabbing to frames for bulkheads or whatever is a potential point of ingrese for moisture. Once the moisture gets behind the foam you will not know. Flexing of the hull or thermal movment add to the stress on the adheasion of the foam to the hull. The nature of a hull below the water line, rolling up, also makes shedding moisture difficult. There is no reason good ventilation passive or mechanichal and a interior ceiling fixed or removable won't keep a well insulated dry hull.

[reed1v]

Originally Posted by Rustic Charm

Mine doesnt have any foam below the water line and ive not had any problem with condensation below the water line.

When i was doing up the inside under deck two years ago i had six months without any foam, including one side above the water line and condensation was like rain on some days. But not since i installed the foam.

Someone suggested 'batts' bad idea if they get wet.

We use to sail a lot in the extreme latitudes. Condensation was a big issue above and below the waterline.

[SailingValkry]

Originally Posted by GordMay

Greetings and welcome aboard the CF, Samantha.

Thank you

[ausnp84]

Originally Posted by reed1v

If its soggy, its open cell foam. Closed cell foam should not absorb any moisture. If the steel is painted with epoxy and then closed cell foam, should last virtually forever. The foam is needed to prevent condensation, especially below the water line where cold water meets warm air in the hull. Someone said not to foam below the waterline. Tell that to the US Navy. Works on their subs, will work for you.

Nope, it was closed cell - about 40 years old, but definitely closed cell. As Cruisingscotts noted, once the foam starts to separate from the hull, or has breaks in it, or the wooden firing strips start to rot, or any other reason where there's a break in the foam and the individual cellular bubbles are weakened or compromised, it can (and does) start to break down, allowing for moisture ingress.

As for foaming below the waterline, I watched a wooden boat sink that was foamed below the waterline, as it sprung a plank and they couldn't find the leak. 6" below the waterline is fine, but I'd hate to have foam going so deep into the bilges that it started absorbing any moisture that pooled down there.

nathan

[RaymondR]

Originally Posted by SailingValkry

1. Do we have to dismantle the interior and retreat the inner hull of the boat?
If so, how often?

2. What is the average life span of the interior treatment of the boat?



Samantha

You don't have to dismantle the interior but it is extremely helpful to have good access to all areas for inspection and repair if required. If there are areas where you cannot access hull plate for inspection you can check the plate thickness from the outside using an Ultrasonic Thickness Tester but the presence of these areas in a steel hull is not a desirable characteristic.

I have never seen an estimate of the average life span for the interior treatment of a steel boat however mine is 28 years old and in most of the interior the original coating of vinyl over epoxy primer is still in excellent condition.

The key to longevity of both the coatings and the underlying steel appears to be whether or not moisture is present for longish periods of time. I would say the most important thing is keeping water on the outside where it is supposed to be. Although not impossible this can be fairly difficult to achieve.

[hpeer]

Our small boat is 30 years old. Long story one winter she got a lot of rain water in that sat in the bilge nearly to the floors (through the engine contro cable) That destroyed a lot of the origional coal tar epoxy coating creating rust. I'm still dealing with it years later. I find some, I attack it, I get maybe 70%, do it again next year. Keep whittling it down. Almost gone, I hope.

When we blasted the hull 2 years ago I found some rust spots, scary. In each location it was because of a long term top down water leak. Now, with some experience, it is not a big deal to fix PROVIDED your can get to the inside. Really sucks to have to cut out a perfectly fine steel fuel tank under you cockpit to fix a hole under it. I'm now doing my own welding and am finding that if I'm more aggressive, just have at it and not fiddle around, things work better. Cut it out, weld it up. Out on a doubler on the inside or out as needed.

In the process I found a lot of the sprayed on foam had allowed moisture under it. It was a real pain to get it off. Grind, cuss, sand, cuss, chip, cuss, blast, cuss, vacum, cuss, etc.

Our big boat is also 30. In general the interior hull is very good. However there are a couple of spots where repairs have been done. One under a sink, and the other under a refer. Both were long term drips. Deadly. There are some other problem spots, but we keep an eye on them. Sometimes it's not easy to properly paint a steel Boat in the water. Our lazarett isn't insulated and it gets a fair amount of condensation from me breathing in there while cleaning up the area. We had found a top down leak in there causing rust. It was real hard to get the area dry for the epoxy. I ended up using a heat gun on high for about a half hour. Nasty job.

I'm not a huge fan of the ultrasonic testing. From my personal experience the problem spots can be very small, you would have to be lucky to find it with a tester. Not saying don't do it. I'm saying a very detailed personal inspection by you self is your best way to go.

Looking around the yard at similar aged plastic boats and seeing the issues they have I'll stick with steel.

We live part time on our boat all year, Delaware. Been right cold especially last winter. We do get condensation especially around the hatches. I don't know what you're could do about that: steel, plastic, or fero. When it's 10°F outside stuff freezes.

[Rustic Charm]

Mine is 36 years old now and those places on the high walls, apart from being dusty look absolutely fine from their first paint job.

Ive had rust, all on the inside (apart from the toe rail) in small pieces like 50 cent coin size. Also, thin around the engine room where previous owners let water and dirt accumalate. Likewise, my small bilge was very rusty, but again from allowing dirty water sit there for probably months or years on end.

Id strongly recommend, where ever possible using two pack paints, at least the primers, inside. A 2 pack red oxide on cleaned metal and the a two pack primer. I use norglass which means inside i can use a singke pack product kver the two pack primer. sticks and lasts.

[Steadman Uhlich]

Originally Posted by Rustic Charm

Mine doesnt have any foam below the water line and ive not had any problem with condensation below the water line.

When i was doing up the inside under deck two years ago i had six months without any foam, including one side above the water line and condensation was like rain on some days. But not since i installed the foam.

Someone suggested 'batts' bad idea if they get wet.

Good post!

Others above too. But I really liked this one because the observation says something about the difference in condensation, which is so important for the boat health and the comfort of the inhabitants too.

[KISS]

Originally Posted by SailingValkry

1. Do we have to dismantle the interior and retreat the inner hull of the boat?

I definitely would. There's no other way to know for sure the condition of the hull/coatings. Gutting also provides an opportunity to rebuild the interior so that you have easy access to inspect all parts of the hull, which is very important for a steel boat, but not always accomplished in the original build.

If so, how often?

Once, assuming you do it right.

2. What is the average life span of the interior treatment of the boat?

Forever, provided it's done properly the first time and then maintained.

Done right, a steel boat can be much less maintenance than the typical glass boat.

Done wrong, it can be a horror show.

...which is why you need to be sure than it's solid at the outset.