Steel boat vs fiberglass

[bogranjac1]

Just wondering about steel boats :

Would a steel boat be more comfortable in regard to climatic conditions in a cold climate such as PNW or in the heat of Florida ?
Obviously one would have heating in PNW and A.C. in Florida, but one of the two climates must be more acceptable.

I know a chap in Innisfail ( very tropical Queensland ) that just could not be in his boat through the summer even with A.C. running - deck was unbearably hot and radiated heat throughout the boat.
On the other hand a steel boat would need 24/7 heating and would there be a river of condensation running down the insides.

Opinions plz as steel boats seem a LOT cheaper.

 

[FF]

"Obviously one would have heating in PNW and A.C. in Florida, but one of the two climates must be more acceptable."

Regardless of the hull material if the boat is not insulated it will be uncomfortable.

Either GRP or steel can be sprayed with foam insulation , then trimmed to smooth with a tree trimming blade in a Jitterbug, then covered with a pretty ceiling.

 

[Captain DJ]

Refitting Old Steel Boat

I got this https://youtu.be/w954lDdKm8E from one of the threads here.
I have subscribed and watched them all.
In this video I look at whether it makes sense to buy an old steel boat. In the end I decided just to buy one and find out for myself.

If you are going to buy, watch his videos. Comparatively, looks like you found an even better deal. But watch his first vid on what he found (amazingly similar boat) and tell me.

 

[dutch-barge]

well we have a steel boat from 1930 and it is perfect...yes you need to remove rust and paint...but when you do so it is just upkeep.....also you do not have to worry about floating logs in the water...since the steel can take a licking and keep going

Yes steel boats have a bad rep in the USA, but look to Europe...where there are steel boats stil merrily cruising and they are over 100 years old. !!

 

[dutch-barge]

maintenance on glass fiber ..the constant waxing ...!!!

 

[Remedy]

Wow that boat is cool. Seems reasonable price to me. I own a steel boat. If you insure the boat they will require an ultrasound test as prerequisite to underwriting. So be sure and order one during pre purchase survey. Steel boats are a bit more technical, by that I mean the boats require more knowledge and careful attention to rust, galvanic corrosion and electrolysis. Mistakes or deferred maintenance with these can cause serious problems. Knowledge of coatings and prep become extremely important. And as been mentioned before, steel rusts inside out in many areas and access to interior spaces becomes important. A sink connection dripping which runs down and puddles under a tank and lay against a stringer for example can cause plate wastage which may or may not be picked up during an ultrasound test. UT tests are good for identifying large areas of plate wastage but most likely issues you might encounter are small areas of corrosion like the dripping pipe example. As for some of the other differences. Steel boats can feel cold inside because steel is an excellent conductor. However if properly insulated this can be greatly reduced especially if the boat doesn't sit too deep in water. Insulation also reduces sound as well. And incidentally I wouldn't buy a steel boat with spray in polyurethane foam. A lot of Chinese boats use this method. It does have great R value but is flammable as hell and hard as to chip out if work (welding) needs to be done, and it will. Wool is my preference. Another difference is steel boats carry their weight differently and I think ride a little better when tossed around. Lastly, there is a reason you don't see many small ( under 40') steel boats. Steel is obviously very heavy and to get a small boat to have good stability characteristics I would worry scantlings would have to be reduced to such a degree as to eliminate any advantage strengthwise steel has to offer. Best of luck .

 

[Doc Holiday]

Hello All,

Tomorrow I am going to see a steel boat as I plan to start cruising the Trent system and then do the Loop solo. I couldn't find much on this forum about steel boats.

Any thoughts out there? The good, the bad and the ugly.....all opinions and advice is very welcome!

Here is the ad

https://www.kijiji.ca/v-powerboat-m...le/1423717345?enableSearchNavigationFlag=true

We've had a steel trawler for 12 years. 16,000 nautical miles including 3 tours of the Trent Severn waterway. The hull and deck paint requires a little touch up each spring but nothing too onerous. If you keep on it there's no issues. Make sure you have new zinc sacrificial anodes if you're doing the loop though.

 

[MOJO]

I have to correct one comment by Remedy above. Steel is not an excellent conductor of heat or cold. It is actually a rather poor thermal conductor, on the lower end of the thermal conductivity scale of all metals. By contrast, aluminum is at the top of the scale. Think about welding steel... you can heat the steel to melting (around 2500 F) and yet less than a foot away from the weld the steel is still at ambient temperature. If steel conducted heat well, this wouldn't be the case. But, steel does hold heat well. It is slow to heat up, and slow to cool down. So, if a steel boat is sitting in cold water, once the steel cools down to water temp, it takes a fair amount of heat (sun, wamer water, etc.) to raise it back up. On our well insulated boat MOJO (www.mvmojo.com), as live-aboards we've observed that the below decks interior of the boat does stay cooler than previous fiber glass boats we've owned. Since we're warm weather cruisers, that's a bonus!

 

[Sea Word]

I have to correct you mojo, steel is an excellent conductor of heat, compared to wood or fiberglass. I’m not sure where it would land when aluminum is thrown in the mix, but I suspect it would be a lot closer to aluminum than the other two hull materials.

 

[MOJO]

I have to correct you mojo, steel is an excellent conductor of heat, compared to wood or fiberglass. I’m not sure where it would land when aluminum is thrown in the mix, but I suspect it would be a lot closer to aluminum than the other two hull materials.

look it up. Google "thermal conductivity of metals". steel is in the lower third of the chart.

 

[Sea Word]

look it up. Google "thermal conductivity of metals". steel is in the lower third of the chart.

Lol okay but we aren’t talking about “metals” we are talking about hull materials. Those are commonly wood, glass, aluminum, or steel. Of those 4 materials steel is on the upper end of conductivity. Not because steel is an exceptionally good conductor, but because wood and glass are exceptionally good insulators.
It’s all relative.

 

[MOJO]

Lol okay but we aren’t talking about “metals” we are talking about hull materials. Those are commonly wood, glass, aluminum, or steel. Of those 4 materials steel is on the upper end of conductivity. Not because steel is an exceptionally good conductor, but because wood and glass are exceptionally good insulators.
It’s all relative.

Maybe the confusion is in the term conductivity. I'm using it in the physics sense, of moving the heat from one portion of the material to another - the rate at which heat passes through a specified material, expressed as the amount of heat that flows per unit time through a unit area. Heat flows thorough steel fairly slowly vs other metals. No debate vs wood or fiberglass, which are considered thermal insulators as opposed to thermal conductors. But there's a vast difference between steel & aluminum. Aluminum is at the top of the thermal conductivity scale. As I said, steel is thermally not very conductive (vs other metals). It is slow to heat up but holds it's heat for a long time. Ditto for cold, slow to cool down but once cool it takes a lot of heat to heat it up again. Absent good insulation, it takes more a/c to keep a steel boat cool in the sun and more heat to keep it warm in cool climes. Aluminum is much worse - it heats & cools rapidly and conducts heat through out it's surface easily and gives up (releases) it's heat fast also. But, with good insulation, steel can mimic wood or fiberglass in terms of it's thermal properties whereas fiberglass and wood will be hard pressed to mimic steel in terms of strength (per unit area)!

Many years ago we found a ceramic paint additive called Insuladd. It's a very fine powder like substance made from hollow ceramic microspheres (beads), mixed 1 lb of Insuladd with 1 gallon of paint. It was developed in association with NASA and used on the space shuttle, etc. You can mix it with paint and it offers significant heat reflection - in both directions... reflects heat away from the the boat in the summer as well as keeping heat in (reflecting it back into the boat) during the winter. We painted the roof of MOJO with it 19 years ago. It knocked 10 degrees off the ceiling of the boat in south Florida summer temperatures. It's still working even with several subsequent coats of new paint. Not horribly expensive either, about $20 per pound. Since you have to paint steel anyway, mixing this stuff with the paint offers significant insulation at minimal cost and no extra effort. www.insuladd.com

 

[FF]

"Since you have to paint steel anyway, mixing this stuff with the paint offers significant insulation at minimal cost and no extra effort."

We tried it with less success on bus conversions , with aluminum roofs.

Today the house trailer roof paint has titanium which is a great reflector,and has great flexing & sealing properties as trailer roofs expand and contract a great deal.

Its a bit softer than deck paint so is best in low foot traffic areas , tho at about $25 a gallon for the best made , its water based so a top coat is a snap.

 

[bgillroy]

Suggest you inspect the hull plate and weldments very well. This is best accomplished via NDT testing equipment. It is possible that years of fillers and coating systems may mask steel deterioration. Once again inspection of a steel hull takes NDT equipment and technician experience.

 

[MOJO]

We tried it with less success on bus conversions , with aluminum roofs.

Aluminum is a bear to paint, with or without an additive. Most do it yourself aluminum paint jobs I've seen fail in the first few years due to lack of scrupulous prep including acid etching. Steel, even with the prep required for it is substantively easier!

 

[Arun52]

The construction of the Arun Class boats like mine is unusual in that they built the same hulls out of 3 different materials.
The first 3 prototype boats were built out of laminated wood, 3 layers of Agba over laminated frames.
Another 42 boats were built out of different GRP resins as the technology improved, Orthophthalic, Isophthalic and finally Epacryn.
Only one boat 52-030 was built with a steel hull.
Every crew that operated them agreed that the steel boat had the best seakeeping ability by far, even though it was the slowest.
The steel boat cost was 3 times the price of the GRP boat at that time so was considered too expensive.
Likewise the timber boats, construction and upkeep were prohibitively expensive.
I built many commercial steel trawlers back in the late 70's early 80's.
Many of these boats are still working today.
The secret was never using black steel. Every piece of steel was pretreated.
Trying to build a boat out of black steel and then blast the inside you can never get into every corner especially inside tanks etc.
Given the choice of 2 identical boats one built from plastic and one from steel I would pick the steel boat every time.

 

[dhays]

I've never owned a steel boat and I'm pretty ignorant in general, so forgive me if this is a still notion....


It seems to me I'd be a bit concerned if I couldn't access and inspect the interior of a steel hull. I'd be worried about possible corrosion in a hidden interior area of the hull that I couldn't readily access. Otherwise, it seems as if regular inspection, followed by some wire brushing and painting of rust spots would a relatively straightforward exercise.

 

[Arun52]

It depends what material you are used to working with.
Do you really know what is going on internally on a plastic boat?
Tapping and measuring moisture content on a GRP hull does not always give a true indication of serious issues that may be hidden.
The RNLI has spent many years testing their boats and found Laser Shearography the best so far.
There is a good article online "The practical use of NDE for the assessment of damaged marine composite structures.""P. J. Sheppard, H. J. Phillips & I. Cooper."
It list many of the different methods that have been tried and the pluses and minuses of each method.
Testing a steel hull for defects and repairs is usually far easier and cheaper.

 

[FF]

"Aluminum is a bear to paint, with or without an additive. Most do it yourself aluminum paint jobs I've seen fail in the first few years due to lack of scrupulous prep including acid etching."

This was true in the past ,but the air police outlawed (or made purchase difficult) the primers that were effective.

Rustoleum did its homework and their water based aluminum primer is excellent.

It also is the only primer for galvanized metal that works long term.

After drying for a couple of days the Rustoleum can be painted with oil or water based top coats

Our hassle with with ceramic in the paint was its not being effective as insulation,, not in falling off.

 

[Mikala]

Here is a recent example of the differences between steel and fiberglass from Fort Lauderdale.

This steel hull was hit by a plastic Sea Ray that was doing 30 kts.




Here is the Sea Ray.

 

[Nomad Willy]

Now I assume you’re going to show us the small steel boat hitting a big FG boat at 30mph.

 

[bgillroy]

Strongly suggest you hire NDT technician to test steel before you buy. No way to see the worst of it otherwise. Check with CG or Sams or Nams surveyor for qualified tech. Lead. Good luck.

 

[balder8]

Given the choice of 2 identical boats one built from plastic and one from steel I would pick the steel boat every time.[/QUOTE]

Hi everybody,

I owned 7 Fiberglass boats and now, I am travelling in Europe with my North sea Trawler 57' OC BALDER VIII, strongly built in steel.
On the way from Holland, near Brest, on the french west coast, in rough weather, we hit a huge piece of massive wood, which stayed stucked on our bulb, underwater. I heard nothing, and this 60 Tons boat didn't slow à 7,5 knts.
When arrived in the Marina Moulin Blanc in Brest, we discovered this piece of wood.
Others were laughing, telling us we should now, after the table, look for chairs.
This to say that I feel definetely safer at sea with my 8mm steel hull and deck.
Of course, I have 3 local small rusty spots to clean at the moment. Not a big deal when I remember the polishing work I have had to do every spring on my fiberglas yachts...
Aboard BALDER VIII
mmsi 227 399 280
currently underway Marina Lanzarote Canary Islands Spain

 

[Mako]

Reference to new builds, I have found a big difference in cost per ton for a steel boat versus fiberglass coming out of an existing mold (ie- FG is cheaper).

Another factor to consider is whether you live aboard full time and can immediately hit rust as it shows, or if you leave your boat moored for weeks or months at a time.

Also in general I believe that fiberglass has better resale value than metal.