Settle an agruement!!!

Brad Embleton · Addict Joined: 13 Jan 2003 Posts: 511 City: Niagara Falls

Will using a fat sac possiblly crack your hull?

jryoung · Ladies Man Joined: 19 Mar 2004 Posts: 7664 City: Man Jose

Only if you drive the boat like a jacka$$ in really choppy water (assuming the boat is in good condition) as far as I know. Remember to drain it though when the boat is not in the water.

Erik · Posted: Jun 10, 2004 4:33 pm Post subject:

Its difficult to say.

But this is a good and solid question. This is the kind of thing forums were invented for. Let's get it on! **ding**

I have thought about it at times, especially when I find new gelcoat cracks on my Ski Nautique. Its a lot less likely with newer boats for sure. On mine, due to its age, my instincts tell me that there might be some possibility of that happening if there is a ton of weight in the front and in the back and you hit some massive chop. Like a car, a boat has a kind of *frame* that *could* flex. After a certian amount of unevenly distributed weight is applied - the stringers could bend and this possibly crack the hull - but I'm talking thousands of pounds!

I know this is a long shot but I work for the country's biggest CAD software company and if anyone has a Ski boat cad model I could run a structural/thermal prediction test. In general I think this is a really subjective question - I mean if you put 1000lbs in the front and 1000lbs in the back and try to trailer it - or even put it on a lift; you'd be playing with fire. Whoever in the bet said it could crack it, wins this bet. Now if you applied real figures (pounds) in the bet, it may be another story. I'm sure the boats are built (over built in the case of Nautique or MasterCraft) to handle considerably more than the weight sticker suggests - even if that weight is concentrated in one place on the craft. Good question though - can anyone else weigh in (no pun intended)?

Brad Embleton · Addict Joined: 13 Jan 2003 Posts: 511 City: Niagara Falls

Erik,

Thanks for the input

Funkster · Posted: Jun 10, 2004 5:15 pm Post subject:

I don't think using a single fat sac would damage your hull,but I think using numerous sacs on rough water over a period of time put added stress on your hull causing it to crack from stress.

DJew Jake · Posted: Jun 10, 2004 7:31 pm Post subject:

I have cracked a gelcoat and warped a hull but it was not the fat sac directly the drain hose crimped and the sac overfilled water pressure then flexed the hull and cracked the gelcoat. However even after that stress the hull seems just as strong in that spot.

Alan C · Soul Rider Joined: 26 Jan 2004 Posts: 329 City: Calgary

ya... or you could buy a tige... and if there is ever any problem with your hull crackin or whatever you just send the boat back... they give u 10k for the trouble and a new boat!!!

chaz28o · Posted: Jun 10, 2004 8:15 pm Post subject:

IMHO the use of sacks and balists only hurts you when you haven't fully drained them - and put your boat on the trailer

In most cases, the trailers were designed to carry the boat - as is from the factory

So.... If your like us - and go at it an hour past your posta Twisted Evil

And then don't want to wait around till all is drained - then invest in a better trailer, IE - get the fat round axles

Of course - if you have 2.5k #'s of sacks in your boat - and you're out wake hopping.......................

Bruky · Guest

Alan C., I would think every company would give you a new boat if your hull started cracking...Tige just takes everything and advertises is as if they are doing more for you than every other company. Maybe they do give you 10k, but I'm sure it's not that simple. They just exploit it to death...like their hull design...

Nor*Cal · Ladies Man Joined: 12 Jan 2003 Posts: 9479 City: Sac

Doubtful that a company would replace the boat for you if it was weighted beyond factory specifications. It is a risk we run.

oshensurfer · Posted: Jun 11, 2004 8:27 am Post subject:

Is the question whether one fat sac will crack the hull or multiple sacs? While driving in the water or trailering?

One fat sac is 350lbs, right? No diff than a lard butt or 2 peeps. I would only be concerned with weight up front in the bow and mainly towards the front 2 feet of the bow. If you're getting air in your boat on the water, yeah, it might do some damage, but I doubt you could crack it based on normal sane operation.

If you overload your boat, you would be more likely to do some damage. Like was said above... ALWAYS pull the weight out of your boat as much as possible while trailering (draing your sacs/ballasts). There's an uneven pressure on the hull from the bunks when trailered, whereas there is even pressure on the hull for the most part while in the water, unless you're airborne. When we boat camp, I try to load everything I can in the truck, then sparingly add some of the lighter items to the boat. But, that's just me.

MrBlean · Posted: Jun 11, 2004 1:53 pm Post subject:

Erik · Posted: Jun 11, 2004 8:14 pm Post subject:

MrBlean - argh I feel your pain on that. I have found that wakeupdude's post count is far more important to him than actual useful contribution...

Wakeupdude, slow down! and what does that post even mean. Exploit their hull design? Huh? Confused

DJew Jake · Posted: Jun 11, 2004 9:02 pm Post subject:

Erik, I think he is talking about how they natter on about taps an the "convex hull" like they invented it. None the less WU rarley does anything useful.

MrBlean · Posted: Jun 11, 2004 10:36 pm Post subject:

Erik, aFramer - thanks for the moral support. I try to bite my toungue on these things but this dude has an "opinion" on everything. And that's usually all it is, an opinion. No fact, no logoic, no experience - just opinion.

Most of his contributions add nothing useful (or positive - unless he's talking about what he owns/uses). All bit child-ish really.

I'll refrain from making the obvious remark in that regard.

SupraBoarder · Posted: Jun 13, 2004 2:07 pm Post subject:

DJew Jake · Posted: Jun 13, 2004 2:17 pm Post subject:

Oh another boat >> a 19 foot fourwinns we put a 350 in cracked severly int he gelcoat not sure if it was related because the cracks eminated from the button screwes for the cover. FYI ofurwinns would not pay for the repairs to the gelcoat even though the boat was a 2003 (this happen in 2k3) so essentialy they screwed us over.

tryan · Soul Rider Joined: 06 Feb 2003 Posts: 257

in general, additional weight doesn't crack gel-coat, people do.

Erik · Posted: Jun 14, 2004 5:15 am Post subject:

lanceuga33 · Outlaw Joined: 16 Oct 2003 Posts: 143 City: McDonough

Great Topic!

I personally am terrified of putting tons of weight in my boat. Not just gel coat cracks, but everything else involved such as motor and tranny. To me it is not worth it. Maybe if I were a pro or something I might consider. I use a stock ballast center only and believe it or not my wake is great. A friend of mine can pull alot of the inverts and has no problem at all behind my boat. I could not imagine the gas consumption on a loaded down boat either.

I don't know maybe I'm just to paraniod.

Ruune · Posted: Jun 14, 2004 7:04 am Post subject:

regarding the Tigé replacement warranty- the lifeplus 10k warranty was only in 2003, with the composite quadrabeam stringer system. For 2004, they introduced the lifeplus core, which is a completely new and unique design. Although they are not giving you an additional 10k, they will replace the boat outright for the original owner. This includes any type of delamination or structural failure, but I'll have to reread my warranty to see what the disqualifiers are as far as ballast... although I dont remember any.

tryan · Soul Rider Joined: 06 Feb 2003 Posts: 257

eric, that was a pun on, guns don't kill people, people do. adding 'in genral' was my out.

lcap · Ladies Man Joined: 13 Nov 2003 Posts: 10973 City: Homeless

Its dangerous to load a boat to its Maximum Weight Capacity without an understanding of how this number is arrived at.

The capacity plate ratings are for an evenly loaded boat immersed in calm water--Not in rough water, weather or on trailers. Structural warranty claims will be denied even though the nameplate rating may not have been exceeded.

FEDERAL LAW:183.33 Maximum weight capacity: Inboard and inboard-outdrive boats.

(a) The maximum weight capacity (W) marked on a boat that has one or more inboard or inboard-outdrive units for propulsion must not exceed the greater value of W obtained from either of the following formulas:
W = maximum displacement/5 – boat weight/5 – 4 (machinery weight)/5
or
W = (maximum displacement – boat weight)/7

(b) For the purpose of paragraph (a) of this section: (1) “Maximum displacement” is the weight of the volume of water displaced by the boat at its maximum level immersion in calm water without water coming aboard. For the purpose of this paragraph, a boat is level when it is transversely level and when either of the two following conditions are met:

www.uscgboating.org/regulations/boatbuilder/downloads/safeloading.pdf

Whilst Statics and Strengths of Materials was more recent course study than my 5th grade velocity calculations, it was nevertheless a very long time ago.

Consequently, I will defer the explanation of static vs. dynamic loads to Proffesor Mr.Blean.

MrBlean · Posted: Jun 14, 2004 1:05 pm Post subject: Was that really necessary?????

Ralph · Posted: Jun 14, 2004 2:16 pm Post subject:

I think there is two aspects to hull damage & fat sacs:
1. Non vented sac in a locker which can expand and apply pressure directly to the fiber glass.
2. Added weight which stresses the overall structure.

1. Is very dangerous and does cause immediate damage as shown in the moomba outback which put massive structural cracks in the boat. The bag was vented but the vents were kinked closed and the bag over expanded and broke the deck.

2. Is less of a worry IMO, may cause small gel coat spider cracks but nothing structural. Probably cumulative with time.

lcap · Ladies Man Joined: 13 Nov 2003 Posts: 10973 City: Homeless

MrBlean

Our back and forth does not serve the purpose of these forms which is to share and hopefully learn from others. The misspelling of proffesor was intentional and in the same spirit as pompass. Me being a smart ass, my apologies.

Back to the original topic:

Hull design/engineering involves some of the most complex problems in engineering and way beyond explanation in this forum. The 3"X5" version in laymens terms:

The maximum weight on my nameplate is 8 persons or 1,000 (lbs) as derived from my earlier post. If I load my boat to 1,000 lbs and go riding, I have completely different stresses acting upon the hull. Every time I go over my rollers, other boats wake, waves, etc., the hull (part or all) becomes airborne and slams on the water surface, which stops the boat but the 1,000 lbs contiunes to exert stresses upon the deck and hull. Picture the violence of a perfect belly flop.

This is not necessarily bad if the sacs replace the people and the seating they used to occupy. The loads, stresses and ultimate design had these loads (people) in mind (hopefully).

You start getting close to maximum weight ratings, load the boat improperly, point load with lead, improperly install a ballast system, you will experience failure.

Yes as with all engineering, all the calculations have a safety factor included in the nameplate ratings. However, common mistakes in the lay up of fiberglass can result in a 33% reduction of strength from one boat to the next in the assembly process.

Over the next few years this board will be full of posts by guys crying that the manufacturer refused to honor the lifetime structural warranty. Sorry boys, warranties do not cover negligence or abuse. Improper weighting is both.

Finally, the spider cracks in the gelcoat may be cosmetic or a sign of a catastrophic structural failure, it depends on the size, shape, pattern and location.

So, load em up, but remember, "you break it, you bought it."