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View Full Version : structual flex question x-15


rstitson
10-30-2007, 09:56 PM
Ran into a situation this summer on Lake Champlain Vermont I want to get feed back on. Was out in rough water getting close to 4 ft chop. 2 grown son's up front behind windshield along with wife. Spray soaking the back seats. Running into the chop head on fast enough to keep the bow up. Was taking more of a beating than i would like, the walk through window flexed so much it fell into the lip and jammed a couple of times. Had to pop it out. Have noticed some minimal flex with moderate chop in the past by looking at the window lip clearances. Does anyone have experience or knowledge of how much hull flex should be present in a boat of this kind. It is an 2007 x-15. I would expect like a convertible you would get some flex, but I was a little taken back and have some concern about long term structure integrity. We were in another flare up on a lake in Maine, waves not quite as high or choppy but large enough to cause me to run with the waves into a bay and take another angle out and did not notice similar flex during that incident. Would running ballast in the back help soften the frontal impact helping it to ride lower in the water with bow up?

cbryan70
10-30-2007, 10:02 PM
Im not sure this is correct but a buddy of mine has another brand ski boat and his winshield has done the same thing with falling through. There boat has been on a rough water lake its whole life but they have had it assessed and there is structural damage to the hull with it being slightly warped. His boat brand...lifetime hull its claiming nothing is wrong even though they have had it assessed and there is warp in the hull. Go figure their boat company has NEVER replaced a boat due to somthing like this....they thought about fighting it but figure after lawyer fees and such to get a new boat the would be better of just getting a new one or dealing with it to save the cash. Kinda sad some companies dont back up their warrentys

JimN
10-30-2007, 10:08 PM
In flexibility, there is strength. Making something like this to be totally rigid, there would either be no interior space or it would be too heavy for this size. It would also cost a lot more to build. Remember- the interior is mostly air and there's really not that much structure above the floor. For that matter, there's not that much below the floor, either. There's a big void running down the center and there's not that much resisting the forces.

All boats flex unless, as I said, a lot more interior space is devoted to resisting it.

TX.X-30 fan
10-30-2007, 10:22 PM
I can't imagine being on the lake for long in those kind of seas? That is I guess something that could happen to anyone if a freak storm or something blew through. I know my boat is well made, but doubt it is designed to routinely be driven in that kind of condition? If I was to be too far from the dock and 4' rollers started to fill the lake I might head for a cove, anchor and try to ride it out. Cruising fast through 4' wave I would fully expect my tower to rip off and sink.

I know nothing about that lake, but if those are normal conditions I would be in 28-32' boat and not skiing.

From what I know of ski/wakeboard boats they are meant for relatively calm water?

sand2snow22
10-30-2007, 11:11 PM
Im not sure this is correct but a buddy of mine has another brand ski boat and his winshield has done the same thing with falling through. There boat has been on a rough water lake its whole life but they have had it assessed and there is structural damage to the hull with it being slightly warped. His boat brand...lifetime hull its claiming nothing is wrong even though they have had it assessed and there is warp in the hull. Go figure their boat company has NEVER replaced a boat due to somthing like this....they thought about fighting it but figure after lawyer fees and such to get a new boat the would be better of just getting a new one or dealing with it to save the cash. Kinda sad some companies dont back up their warrentys

Gotta be Tige. I know Tige replace a boat here in Oregon, problem with the hull. So sounds like they're lying to your friend. Why have a lifetime warranty in place if you aren't going to honor it?

rstitson
10-30-2007, 11:54 PM
The one time it happened in Maine we were out about 10 miles from dock and just got caught on the way back. It's always a decision when to wait it out in a bay, but at that time it wasn't so bad we felt unsafe. Lake Champlain can get rough, but of the 10 days we were there 8 of them we could always find a protected coast to wake board and generally had better water somewhere than in smaller lakes. That particular day we were leaving and headed to take out after dropping off my older son. Never dropped off my son in Platsburg N.Y had him take the ferry instead as it just kept getting worse. Don't believe the hull is warped as it is just flex and window fits correctly now. I agree there is always a balance with rigid vs flex.. My understanding is that the larger the boat the less they carry their own weight as in the oil tankers. I imagine the cruisers with the closed bows are more rigid as some of the center consoles. My 17 ft glastron has a waffle design on the lower hull of course it is much smaller in surface area and more v shaped which probably reduces the forces on impact. The x-15 is a cross-over with a relatively flat stern and graduating to a v after mid boat. I do want to make sure I don't over stress the boat on a regular basis. Understanding what that is is the difficult part as mastercraft shows it's boats jumping waves in it's promotions.

dmayer84
10-30-2007, 11:59 PM
rstitson, where in VT were you going out from? I graduated from Plattsburgh in 06 my sister is still at UVM and I used to work a camp in west port ny.

rstitson
10-31-2007, 12:10 AM
We rented in South Hero the east side forget the bay name. We have rented on Champlain a few times. Also spent a day on southern Champlain north of Ticonderoga. We were not far from the causeway in South Hero. This particular time was headed up to the gut and across to Platsburgh. Turned around when going out of the gut on the other side as the chop was in all directions getting bigger and decided we didn't want to make the news. We generally boat in Sebago Maine which is a good size lake but not quite as rough as lake champlain. On Sebago some of the roughest water is when it goes for 100+ feet to 30 - feet in a hurry. They had one day this summer where the wind came up and swamped a boat as it was attempting to get out of a protected area.... always have to be careful and not over estimate what your boat can do.

G-man
10-31-2007, 12:12 AM
I don't know how fast you were going but I have had days when it was so rough we crossed the lake at 10-15mph just fast enough keep the bow up. Nothing worse than a flat bottom boat banging across the lake.

TMCNo1
10-31-2007, 07:42 AM
Maybe it time for a 46' Fountain with 2 blown 502's that runs 100 mph on top of 4' swells!

TX.X-30 fan
10-31-2007, 08:17 AM
Maybe it time for a 46' Fountain with 2 blown 502's that runs 100 mph on top of 4' swells!




That's what I was trying to say. :D

Roonie's
10-31-2007, 10:02 AM
I was in similar conditions and had to get back no matter what with a full boat of people. I was 10 ft off shore and going about 14 mph. I have an 07 X2 and it didn't feel like I beat the boat up any as I have been in worse conditions before with a different boat and no problems. I didn't notice anything wrong after words and I went through the whole boat.

About three weeks later I developed spider cracks in my bow where the windshield unit attaches to the seats. The dealer had their fiberglass specialist from the MC plant in TN up and he fixed them as my boat was only two months old.

Related? I don't know but the conditions I was in I wouldn't consider bad as there were other boats out as well. Granted not conditions I would waqnt to be out in daily but one time shot for 10 minutes I would think would be just fine?

edit; my windshield was closed the whole time with door in place and it never fell through.

dpolen
10-31-2007, 11:38 AM
Maybe it time for a 46' Fountain with 2 blown 502's that runs 100 mph on top of 4' swells!


Now that would be a fun 2nd boat to have!!! Primary boat being an MC of course!:D Gotta make sure they throw in the bikini gals to ride on the sundeck...that's a must for a toy like that.

kjohnson
10-31-2007, 11:46 AM
Most boats are designed for severe structural loadings. However, every possible situation cannot be analyzed. Don't overload the boat and be careful in rough water and you should be ok. I am a structural engineer (and I did spend the night at a Holiday Inn Express last night) and I used to analyze large dredge boats for the Corps of Engineers. I also own a PS 190 and I try to take it slow in rough water. I don't like my bow bouncing up and down, which could cause the hull to crack over a period of time as fiberglass is a brittle material and does not flex that well.

Sodar
10-31-2007, 12:01 PM
Maybe it time for a 46' Fountain with 2 blown 502's that runs 100 mph on top of 4' swells!

Fountain does not make a 46'!! 8p

Sodar
10-31-2007, 12:04 PM
It is all in how you run your boat. I had had my 197 out in 4' swells, when a freak storm rolled in on Havasu this summer. I did not even spill a drink or take even the slightest pounding. Sometimes, running straight into the swell is not the best method. I always try to quarter the swells or even run in the trough, where there is a rolling motion, rather than a pounding.

cbryan70
10-31-2007, 12:18 PM
Wow your good!!! What did they have to do to get the boat replaced?

Gotta be Tige. I know Tige replace a boat here in Oregon, problem with the hull. So sounds like they're lying to your friend. Why have a lifetime warranty in place if you aren't going to honor it?

Jerseydave
10-31-2007, 05:09 PM
Similar thing happened to my '03 230VRS, crossing my own wake after making a turn the center of the windshield fell in and got stuck. I had to take the screws out and slide the section up the track and then re-assemble it.

These boats are not as rigid as a closed-bow boat, certainly nowhere near as strong as a performance-type hull (Fountain, Formula, Donzi, etc.) Performance boats have multiple bulkheads to withstand the harsh pounding of heavy seas.

Bottom line, go easy in the rough water or stay out of it. Your boat (and kidneys) will thank you for it. :)

TMCNo1
10-31-2007, 05:27 PM
Fountain does not make a 46'!! 8p

Ok, I was 1' off, will this 47 Lightning with 2 Mercury 850's be close enough?

JoshBuzz
10-31-2007, 06:16 PM
why would you abuse your MC like that?!?

I'm callin' BPS!!

haha, just kiddin'!!

Sodar
10-31-2007, 06:56 PM
Ok, I was 1' off, will this 47 Lightning with 2 Mercury 850's be close enough?

Why be a p*ssy? Merc 1200's are the only way to fly. The only thing that would out do a set of those would be a set of Sterlings or Pfaff's!

TMCNo1
10-31-2007, 08:07 PM
Why be a p*ssy? Merc 1200's are the only way to fly. The only thing that would out do a set of those would be a set of Sterlings or Pfaff's!

:uglyhamme I just wanted to get to a little over 100 mph, not to the Moon!

JBaker
10-31-2007, 08:09 PM
I do a lot of my boating at Lake of the Ozarks where Fountains, Formulas and Bajas rule the water. I went with an X-80 for this exact situation, but even it is no match for summer weekends. I have a 37' Sea Ray for those days, but I have never been a go fast fan.

The problem with this, and I admit I am part of the problem, is everyone is tired of getting beat up so they buy a bigger boat, which makes bigger waves, and the vicious circle begins.

rstitson
11-01-2007, 12:32 AM
I like the idea of quartering, which I probably should have done and tacked to where I wanted to get to. Generally that is my mode of operation... in this case I was hugging the shore and not sure I wanted to venture further out... will next time. In rough water I always slow down as slow as I can and keep the bow up to prevent taking major water over the bow. This was my first year with a inboard, so I might have been able to take it down a notch ... but maybe not. Thanks for the feed back ..... even the humor. On this particular day the only other boats on the lake were bass boats from a major tournorment. Most were staying in protected areas though some were in the rough and doing pretty well.

Benny Boy
11-01-2007, 10:59 AM
TMCN1: I just wanted to get to a little over 100 mph, not to the Moon!
The best compromise: PS 190 in 4 foot chop. You get halfway to 100mph and bounce halfway to the moon.

defender1009
11-01-2007, 09:52 PM
I actually had the same problem on my old 2001 Malibu---any decent sized wake and the window would fall through and have the flange jam in the driver's side seam...drove me CRAZY.

I actually had the boat with me going through TN once, and I stopped by the Bu factory---they pulled a couple guys off the line and replaced the whole windshield on the spot......Never had the problem again.

Not trying to make a Bu ad here, just pointing out that it may be tolerances in the windshield, or each side may be mounted a hair too far outboard.

cbryan70
11-01-2007, 11:17 PM
Not going to lie that is customer service at its finest...

defender1009
11-03-2007, 12:58 AM
That's what I thought too.....unfortunately the Malibu dealer I bought from sold out, and things were never the same after that.....Funny how a bad dealer experience can ruin your impression of a great boat, no matter the brand.

Fortunately for me, I was trailering my Malibu over to MYMC regularly for routine service, and that's when I got bitten by the Mastercraft bug. So far I've only gotten to take 1 ride on my new toy this season, but I have a winter's worth of little harold-like projects to get ready for CSM 08'. (Sorry for the semi-threadjack).