Building In Steel ?

[Alan Wheeler]

Just to be clear, an anode will not stop rust due to reaction with oxygen. As far as I know anyways.

[Steve Kidson]

Steel boats usually rust from the inside out; nooks and crannies in the bilge will retain moisture that will start the rusting process.

Today's latest coating systems will greatly reduce the maintenance required on not only steel hulls, but those of other materials as well (timber, FC etc).

Hull materials will always provoke great discussion, and usually a polarised diussion will result.

All hull materials have both advantages and disadvantages, and it is a brave person to proclaim there is an ultimate hull material that will, under all circumstances, outperform all others.

All of us have differing cruising grounds, budgets, opportunities, experiences and opinions. What satisfies some will have shortcomings for others, and we need to acknowledge that.

Wheels, for me "FC rocks" , (excuse the pun), and if any one hull material polarises the discussion, it is FC.

Fair winds

Steve

[Yachts66]

I'm curious Steve, what is it about FC that excites you so? Having spent the past year in an intensive search for a boat I can tell you, the few that are out there sell for near nothing and are almost impossible to insure.

Regards,

TJ

[Alan Wheeler]

TJ, that issue maybe true, but it doesn't mean FC is not good. One major advantage for me, we got one heck of a lot of boat for the price. When we come to sell, we are not going to get what a Steel or GRP material will get, but we didn't pay that int he beginning.
But the result is, we have a boat we absolutely love, is strong as, is lighter than steel but nearly as strong and in some instances, a little stronger. Certainly harder wearing. And has no issues of corrosion. She sails like a dream, certainly no record breaker, but that is due to design, not what she is made from.
As said, there are advantages and disadvantages of ALL materials. The only perfect material would be Titanium, but no one could afford it and even fewer could work with it.

[CaptainK]

18-04-2006
Steve Rust once whispered in the wind

About an early post about coating plastic with glass and resin. I am not sure why you wanted to do this but with the exeption of PVC, epoxy does not bond well with plastic. I use small plastic containers and bowls to mix epoxy and after several batches it builds up in the container. After it dries all I have to do is flex the container and it pops loose sometimes even in one piece so I have a nice little epoxy bowl.

Well Steve.

Sorry for not answering this any sooner!! When I mentioned about the PVC. It was a little experiment that I conducted last year. And so far the results are very good!! The fiberglass and resin held on like a dog on a piece of meat. It wouldn't let go. It stayed on!!

I was just basically, trying to find ways to build a big boat for a cheaper price range. That was the reason for that experiment, that I conducted last summer. To answer your question politely.

[Steve Kidson]

TJ

To echo Wheels' reply, the lower cost of an FC boat allows me to have more boat for my buck. I am into cruising, not racing around the buoys, and any perceived weight/speed issues do not concern me.

I have a professionally built hull that is over 25 years old, is very fair, and shows no signs of armature rusting. At present we are coming towards the end of our fitout project; she is sitting on the hard in front of my factory. A 32' yacht in the middle of a factory area always generates interest, and We get lots of people stopping to look at the boat, and to a person, everyone thinks it its fibreglass until I tell them otherwise.

We are fitting her out to enable comfortable weekending/coastal cruising for 2 maybe 3 people.

In summary, its what I can afford to allow me to safely and comfortably follow my dream.

Fair winds

Steve

[Steve Rust]

I have a friend who was part of a group that built a Roberts 53 in steel. He had a falling out with the group and left the project after welding up the hull and deck but was never properly payed for the work. 20 years later he tracked the boat down finding it all but abandoned in a boatyard for the last 12 years and gained ownership of it. The bilges were full of rainwater and the interior was trashed but the interior surface of the steel showed few corrosion problems. The bilges had been painted with coal tar epoxy.

[Brent Swain]

Zinc will protect a certain amount of metal totally. The more exposed metal, the quicker the zinc will disolve, so it isn't a solution for the whole bottom. It will protect quite a large area.
I have a bige keeler ,which has spent a huge portion of her 22 years drying out on a beach, as I've never ,in that time, paid to tie her to a dock. Thus the keels have been bare on the bottom for all but a couple of years of that time. If there were corrosion, the keel bottoms would be uneven, which they are definitly not. Where I've ground spots on the hull, you can still see fresh grinder marks a couple of years after, something you wouldn't see if there were corrosion.
I don't have the means of posting photos.
FC lighter than steel? Not likely. FC weighs between 10 and 15 lbs a square foot ,the weight of 1/4 inch to 3/8th inch steel plate. Plate that heavy is only used on boats in the 45 to 70 ft range.With origami boats , structural angles and flatbar weight is minimal.
FC boats are so cheap that they let you get cruising far earlier than other boats, vitual disposables.The gear off them can be transfered to another boaat some future date ,as they sell for far less than the cost of the gear itself .
Brent

[Brent Swain]

Zinc anodes must be welded on. A bit of corrosion around a bolt , insulates them from the hull. A client did a circumnavigation in one of my 36 footers with a zinc bolted to the rudder and the zinc looked almost as good after a 7 year circumnavigation as it did at the outset. It had no contact whatever with the rudder.
Brent

[Alan Wheeler]

I have to disagree with several points you have made Louis. Do a search and read some interesting stuff we ahve talked about here before about FC. The conclusion was, the a ggod hulls and bad hulls in every medium used. I can show you junk in steel and timber. I am sure you can show me the same in FC,. But I can also show you some very class acts down here in FC. I think we concluded that FC must be built very differently down here. Not sure. But I have a 46ft full keel large volume FC hull that comes in at only 26,000KG. Beautifly built, strong as and sails like a dream. I love her. But I really don't want to get into an argument. I just think you should keep a little more open mind,n that there are good hulls and bad hulls in material.

The other point, I have never welded an anode to any hull. I would nhever consider it. I have had no issues over many years. The importance is making sure you have a good clean connection to begin with. After that, it never has a problem. I would say your mate never bolted it correctly to begin with.
Just IMO. cheers.

[Jeff H]

And just to keep the record straight, the panel weight for a typical under 40 foot long Ferrocement boat is 5 to 7.5 lbs (depending on percentage of reinforcing used) roughly the same weight as a steel boat plated in 3/16" to 1/4" plate. Depending on the actual design of the ferrocement materials involved, for an equal weight that typically results in the F.C.having roughly 1.25 times the bending strength, 3 times the stiffness but only between .8 and .9 times the impact resistance of steel.

Jeff

[Alan Wheeler]

Thanks for those figures Jeff. They make more sense to me than other figures thrown around in the past. Very interesting.

[Brent Swain]

I've weighed FC panels and have never found one weigh less that ten pounds. Most are closer to 15 lbs. Try it. You'll find a huge difference between theoretical weight and actual weight.
Make up FC panels. Bend one, then bend 3/16 plate . See which is more likely to leak. Theory is light years away from reality.
My first boat was FC. I lost it on a Fijian coral reef, just north of Beachcomber island. It broke up like a watermelon dropped on a sidewalk in 15 knots of wind with not that great a fetch. Had she been steel , she wouldn't have even been damaged in those conditions.
FC is strong at sea. Ive never heard of one being dammaged at sea by weather. Hit a solid point and it is extremely fragile.
If I didn't have the option of welding to the hull , I'd put a bit of stainless weld around the bolt hole in the steel strap of a zinc and use a stainless bolt. This way it would be stainless to stainless contact. I'd get a tack on it at the first oppotunity tho. I've seen steel hulls coroded badly with bolted on zincs , so wouldn't risk a bolt on contact any longer than neccesary.
Sure my friend had a bad contact. That was my point . It isn't worth the risk.
Brent

[Alan Wheeler]

Brent, you NEVER, use SST anything under the waterline. Under water, SST is no longer SST. Secondly, you NEVER use SST weld on mild steel. It will eat away at the interface of the two dissimilar metals. Yes it is dissimilar enough to cause a problem.

The FC panels you tested are more than likely of the same problems that gave FC a bad name in the first place. Poorly and improperly constructed. I also know of a hull that is on a reef in the Islands. Still there by the way. Being pounded by storms and has been there for many years. I know of boats in NZ that have been in major groundings that have lived to tell the tale, and are repaired and remained without issue, still sailing years later. One was such a dangerouse grounding, that if it were steel, it would be on the bottom. Does that mean I suggest FC bullet proof, no way. But there are some very strong hulls, light in weight, new and old down here in NZ.
Brent, I am not arguing any point that FC is supperior here. I just think it is silly to suggest one medium is "the best". There are bad FC hulls, bad steel hulls, bad Glass hulls. There are also good in all the above. It depends on many factors way beyond argument here.
As I have also said in the past, I know of two Steel boats that I would never want to go to sea in. The welding is so poor, I cringe at the thought of them. Does that make all steel boats bad, I would be silly to suggest such a thing.

[Brent Swain]

90% of propellor shafts are stainless and are definitly underwater. There are no corrosion problems with welding stainless to mild steel. Just use stainless rods, or 7018 above the waterline where it will be under paint and non structural.My curent boat , which I've owned and cruised full time in since 1985 and done several Pacific crossings in,and my last boat, which I built in 1976 both have a lot of stainless welded on both above and below the waterline, with no problems whatever.
I've built and designed over 150 steel boats with all stainless welded on both above and below the waterline, . They have crossed many oceans and done several circumnavigations , all with no problems.
No stainless on steel is a myth which has caused many steel boat owners a large amount of totally unessesary grief, if they are naive enough to believe it.
You can reduce the amont of maintenance on a steel boat by 80% by trimming all outside corners with welded on stainless. There is no more trouble free thru hull than a sch 40 stainless pipe nipple welded on , with a stainless ball valve and preferably a sch 40 stainless standpipe to above the waterline.
It's always entertaining when someone with no experience at the subject at hand claims that something which has been working well for several decades "Won't work". Shhhh, whatever it is might hear you.
FC is a tiny fraction the strength of steel no matter how you make it up. Pound on any FC panel ,regardless of how it was made, with a sledge hammer, then try the same with a steel panel the same weight .Until you have tried it, you are speaking out of total naivity.
Brent Swain