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Random Quote: Everything has to eat somebody. (Bruce the shark. "Jaws," the movies.)
I know very little, but have the ability to reason. It seems to me that the foam would be the closed cell type.
Both types of foam are commonly used in most building applications. Some are inappropriate in specific applications. For example, you typically would not use open-cell foam below grade where it could absorb water; this would negate its thermal performance because water is a poor insulator compared to air. (just something I found doing a quick search)
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"poor planning on your part does not necessitate an emergency on mine"
Is this the change you were looking for? Feeling duped yet?
*Trophy 2352WA, now adequately repowered with a 300 hp Mercruiser 350 Magnum*
Why foam in the tanks at all? Wouldn't they be better off "exposed" with ventilation all the way around (including the bottom) the tank. I noticed the attachment angles welded to the top of the starboard saddle tank are not used (not lagged to the stringer). So is the purpose of the foam to stabilize the tank? I don't understand why the tanks aren't exposed (as they are in inboard boats) and their stringer compartments ventilated?
Aluminum is self-protecting when exposed to air. It's when moisture is trapped against it- and air does not reach the surface- that aluminum begins to corrode. Even if the foam did not absorb water (and it does), it would still trap the water against the tank because it has no where else to go. The bilge compartments are totally sealed with no ventilation.
even special Yellowfin foam? you might need to check your facts.
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"poor planning on your part does not necessitate an emergency on mine"
Is this the change you were looking for? Feeling duped yet?
*Trophy 2352WA, now adequately repowered with a 300 hp Mercruiser 350 Magnum*
I knew it wasn't E10 destroying fuel tanks and engine systems...its the foam that encapsullates them. I say class action suit against YF to rebuild every boat ever built...I knew that YF never really had a clue towards boat building. I hope home builders and appliance manufacturers that use foam to insulate attics, windows, and refrigerator/ freezers don't catch wind of this.
I knew it wasn't E10 destroying fuel tanks and engine systems...its the foam that encapsullates them. I say class action suit against YF to rebuild every boat ever built...I knew that YF never really had a clue towards boat building. I hope home builders and appliance manufacturers that use foam to insulate attics, windows, and refrigerator/ freezers don't catch wind of this.
Your quote would have some merit if you knew that YF is just now using aluminum tanks, they used fiberglass in the past.
And wet foam around a aluminum tank is a long standard no no.
Foaming in aluminum tanks on high speed boats is the absolute best way to do things. There are other options on semi-displacement boats, but for fast boats, foaming is the way to go.
600 gallons of fuel sloshing around at 50 kts is hard to hang on to, to say the least.
Here is the problem.
Aluminum “grows” dimensionally when heated, and “shrinks” when cooled down. A lot. A long tank can grow ½” to 1” in length during the course of a 24 hour cycle (night/day). So if you hard mount this tank with bolted straps, nest it between bulkheads, or in any way try and fix the tank with structure, you will not like what happens next. The expansion of the tank will either break the structure (likely) or buckle the tank (unlikely). In either case this will result in 1500 pound battering ram loose below the decks in a high speed boat.
If you pour foam around it, the foam is compliant, it can adjust to the length changes of the tanks as they expand and contract due to temperature. Unfortunately, the foam can absorb some water, or separate slightly from the tank wall, in both cases, water can and will find it’s way into intimate contact with the bare aluminum and poultice corrosion will begin.
The foams that are used to capture tanks are closed cell foams. Depends on the builder, but usually 2-4 lbs density, pretty light stuff. These foams are two part urethanes, and do not absorb much water as a rule. Depends on the brand and type, but figure 2%-10% water absorption per unit of weight. So if you have 100 lbs of foam you would expect around 2 or 3 lbs of water to be in the foam. Higher density foams have lower absorption, lighter foams the opposite.
The trouble is, it does not take much water to cause poultice corrosion, if it is trapped in intimate contact with the tank wall, only a few ounces are necessary. Condensation on the tank walls, high humidity and persistent deck leaks all occur and conspire to make this happen. The corrosion takes place over long lengths of time, usually years.
Decorative anodizing the aluminum is not effective at resisting this corrosion. It is not difficult or expensive to coat an aluminum tank with an effective material to prevent this from happening, such as coal tar epoxy, zinc chromate primer, or an epoxy paint system. The requirement for the coating is that it must expand and contract the ½” to 1” without cracking or breaking at the same time insulating the tank walls from moisture contact.
Most top tier builders provide some type of coating to prevent this not because they are generous but because they do not want expensive warranty returns, which they have usually learned the hard way. I’m inclined to give YF the benefit of the doubt until told differently, as there may be something going on not evident in the pictures. In the meantime, here is a pic of the tanks from my earlier boat, a 35’ Sea Hunter with coal tar epoxy coated aluminum tanks. These tanks were also foamed in. Note that SH has a lifetime warranty on their hull and tanks. My current Fountain uses a paint system to achieve the same thing.
Gorgeous boat. I agree that from what I see, it's tank surgery in about 10 years, depending on wall thickness and a host of other factors. If that matters to you, I would ask that they do the tank (all facets of the job) to ABYC standards.
Well said darbikrash, as the benefit does go to Yellowfin. It would be hard to imagine that between them and the tank vendor they don't have the knowledge of most all these posters in regards to fuel tanks installations. With that said, there are some protective coatings available which may have been used that are clear unlike your black coal tar. Not the same clear he's been suggested to shoot over the gelcoat which would probably be advised against by the factory.
My last boat; 1984 Rampone 25 had foamed in aluminum main tanks. No problems with them when I sold it, 25 years later. I'd buy this boat in 10 years without thinking twice.
Foaming in aluminum tanks on high speed boats is the absolute best way to do things. There are other options on semi-displacement boats, but for fast boats, foaming is the way to go.
600 gallons of fuel sloshing around at 50 kts is hard to hang on to, to say the least.
Here is the problem.
Aluminum “grows” dimensionally when heated, and “shrinks” when cooled down. A lot. A long tank can grow ½” to 1” in length during the course of a 24 hour cycle (night/day). So if you hard mount this tank with bolted straps, nest it between bulkheads, or in any way try and fix the tank with structure, you will not like what happens next. The expansion of the tank will either break the structure (likely) or buckle the tank (unlikely). In either case this will result in 1500 pound battering ram loose below the decks in a high speed boat.
WHAT??? Aluminum's cooefient of expansion is .000023 per degree (Celsius). In other words, a 1 meter bar will grow 2.3 mm if its temperture increases 100 degrees C. That's .09 inches at 100 degrees CELCIUS, which is 212 degrees fahrenheit. If you are getting a gas tank to 212 degrees..you're gonna have a lot of other problems if that tank has or has ever had any gas in it.
And wouldn't a large tank have a baffle welded in that would keep all the gas from collectivley sloshing to end or side?
Joe, thats kinda what I thought. 1/2 to 1 inch increase in length of the tank? gimmie a break. i coated my tank with a truck bed liner material and foamed it in on my project boat and think it will be the last thing i worry about on my boat. The post about the fuel lines holding fuel and failing is interesting and i have to look into that and make sure the fill line i use is ok. It shouldn't have any fuel standing in it the way it will be routed but i will double check that.
WHAT??? Aluminum's cooefient of expansion is .000023 per degree (Celsius). In other words, a 1 meter bar will grow 2.3 mm if its temperture increases 100 degrees C. That's .09 inches at 100 degrees CELCIUS, which is 212 degrees fahrenheit. If you are getting a gas tank to 212 degrees..you're gonna have a lot of other problems if that tank has or has ever had any gas in it.
And wouldn't a large tank have a baffle welded in that would keep all the gas from collectivley sloshing to end or side?
The stuff I read on here sometimes amazes me.
And the tank in that photo is 1 meter long isn't it?
5086 aluminum expands at .000132 inches/inch per degree Farenheit. Exactly. If the tank is 12 feet long, and the delta T is 100 F, the tank expands just under .200 inches, or a little less than 1/4". Not the 1/2" to 1" I mentioned in this case.
I have no idea how long the tanks are in the 42' YF and neither do you. The longer the tank, the more it expands. It was a number intended to help illustrate a concept, which it does.
The use of baffles in the tank will reduce sloshing and the surface effect, but does not change any of the principles or difficulites in mounting the tanks.
I have no dog in this hunt except to say to Mr Detour that he listen to Darbi (John) - He and KernO are friends and that should mean a lot to the others here as to John's expertise. I have met him and Kern for dinner and I have never met two more involved people in boat building in my life. Their trip a few years ago to all the builders in Florida for Darbi's Seahunter and Kern's Venture purchases had all the mfrs scrambling for answers....No opinion on the above, but I would damn sure investigate all that Darbikrash writes....
I truly appreciate the exchange of information and ideas that can happen on this board. I am making a trip up this coming week, and I am certain that we can find THT from Richard's desk.
I have no dog in this hunt except to say to Mr Detour that he listen to Darbi - He and KernO are friends and that should mean lot to the others here as to John's expertise. I have met him and I have never met two more involved people in boat building in my life. Their trip a few years ago to all the builders in Florida for Darbi's Seahunter and Kern's Venture purchases had all the mfrs scrambling for answers....No opinion on the above vut I would damn sure investigate all that Darbikrash writes....
as a matter of fact, where is Kern these days?
i second darbikrash's credentials as an engineer......he knows what he is talking about. It is tough kool-aide to swallow but should be investigated.
Since the most well known and vocal YF owners here always seem to flip their boats within 12-18 months, and most likely dont have info on this subject, are there any YF owners with older boats who care to comment? Now that i think of it, i cant recall any YF owner here who posts freuqently and has a YF older than a couple of years.
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2009 Seahunter 35 twin Verado 300's--For Sale
i second darbikrash's credentials as an engineer......he knows what he is talking about. It is tough kool-aide to swallow but should be investigated.
Since the most well known and vocal YF owners here always seem to flip their boats within 12-18 months, and most likely dont have info on this subject, are there any YF owners with older boats who care to comment? Now that i think of it, i cant recall any YF owner here who posts freuqently and has a YF older than a couple of years.
Certainly interesting comments and I for one appreciate the input; my guess is that Wylie will come on shortly to clarify why his company does what it does and/or advise the illustrious members of THT how he plans on improving any defects herein mentioned, which I have seen his company do. Your request for 1 1/2 year plus YF owners to comment is moot really as aluminum tank installation in YFs took place just within that timeframe (less than 2 years). I do believe however that the original 31 model (anyone correct me if I am wrong), started back in 2001, had aluminum tanks and of all the research, conntacts, networking, etc. I've done with YF owners I have never once heard of an issue occuring with those tanks...so there is your "comment."
I don’t think anybody is suggesting there are any defects here (at least I’m not), based on a couple of photos. A simple question was raised, and I’m sure it has a simple answer.
For many of us, these boats and how there are built are a hobby, and an expensive one at that. Some contribute to these threads to add knowledge, some come on to bash and create unnecessary confrontation. We’ve had some of both so far.
In the last two years I’ve posted 2 separate build threads for two different boats I’ve built, and trust me, I’ve had plenty of “help” from the “experts” in both of these threads. Sometimes, all the well meaning “advice” is hard for an owner to read, people forget the amounts of money these boats cost and the more importantly how much they mean to us emotionally. I encourage Detour to look past the negative comments and to continue to post pictures and progress on his beautiful 42’. After originating 2 of these build threads myself, I can honestly say that the good suggestions for my boats far outweighed the bad, and I learned something from each during the process. Some of the THT comments I took directly to the builder and had the changes made based on the observations and experience of others.
If and when I trade up from my Fountain, the 42’ YF will certainly be on my short list.
That said-fair warning-the standard Florida answer “we’ve never had any problems in the past with (fill in the blanks)” is not going to cut it here, at least with me.
