Shaft broke Right at the Keyhole at the coupler. What slip are you in on J pier?
Prop shaft break on 07 340
- Thread starter hack4alivin
- Start date
We have just lost a prop and broke shaft this past weekend. We were going along about 2200 rpm's felt a vibration and motored revved.. we pulled throttles back and figured we lost a prop. Limped to marina on one motor. They pulled the boat and found half the shaft and prop completely gone!! It also took a chunk out of the bottom of the boat. They too asked if we had hit something and we knew we hadn't... We then found out later in the week that another early 90's Sea Ray DA had a defective shaft. We went to the marina today and they showed us the broken shaft and said that the metal looked defective as it was discolored. We have a 1994 300 Sundancer that we purchased two years ago that had very low hours on it and had never thought that this would be a problem. After searching these pages we can't believe that Sea Ray has done nothing about this problem??!! We are in the process of waiting for two new props as we couldn't find a replacement for one. We are now thinking we should have another shaft made for the the remaining one as we are starting to wonder if that one will depart as well...
flflatrate
New Member
I see many of these break prop shafts especially on the 340's. If its not warranty. you can get a stronger shaft made.
MAKC
Member
- Oct 23, 2006
- 519
- Boat Info
- 1997 400 Sedan Bridge
- Engines
- 3116 Caterpillar
well i think my 2005 320 broke the starboard shaft last night. Up cruising on flat seas at about 3700 RPM when i hear a clunk, the starboard engine revs, smartcraft sounds an alarm and we come off plane to idle. I know for a fact i didnt hit anything. oil pressure was (and still is) good on that engine, water temp perfect, and the tranny spins when you engage the lever. Just no movement from the starboard side. Limped home on the port engine and i'll have it hauled to see how bad it is. Im hoping the prop is still there and that it didnt tear up my rudder or gouge the hull too badly when she broke. I'll start a new thread on this to share info to others.
Where you taking on water?
barryg
Member
- Jun 24, 2007
- 966
- Boat Info
- 2005 320 Sundancer, Garmin 5208
- Engines
- Twin V-Drives 350 Mags
Wow Mike.. That sucks! Please keep us informed as to what you find out.
Good luck!
Barry
Good luck!
Barry
MAKC
Member
- Oct 23, 2006
- 519
- Boat Info
- 1997 400 Sedan Bridge
- Engines
- 3116 Caterpillar
Hey Hack. Not taking on water but i went through all the emergency procedures just like we were. I made sure that we were ready to get in the dinghy with all the emergency gear just in case. Lifted the engine hatch and no water was coming through the shaft seal under the starboard engine. Checked several times and thats still true. I'll keep everyone posted 
Hey Hack. Not taking on water but i went through all the emergency procedures just like we were. I made sure that we were ready to get in the dinghy with all the emergency gear just in case. Lifted the engine hatch and no water was coming through the shaft seal under the starboard engine. Checked several times and thats still true. I'll keep everyone posted
That’s good, scary part about a shaft break is if the shaft leaves the boat. Then you got a big hole down there. In my friends case when the shaft broke the prop came back and hit the rudder, that's what kept the shaft in the boat.
Good luck and I hope it’s not too bad.
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Marcelina
New Member
2nd shaft failure on our 2007 34DA
I complained prior to Bahamas trip and pre $6000 200 hour service check of vibration.
MM had agreed to replace starboard shaft when port shaft failed at 125 hours total time.
I do not believe the shaf that failed last week was a replacement shaft.
MM also made noise that I hit something. I was following my MM sales broker in deep water. (both failures).
If MM replaced shaft, then problem still exists...
If they did not and said they did...???
I complained prior to Bahamas trip and pre $6000 200 hour service check of vibration.
MM had agreed to replace starboard shaft when port shaft failed at 125 hours total time.
I do not believe the shaf that failed last week was a replacement shaft.
MM also made noise that I hit something. I was following my MM sales broker in deep water. (both failures).
If MM replaced shaft, then problem still exists...
If they did not and said they did...???
- Nov 26, 2006
- 7,628
- Boat Info
- 2008 44 Sedan Bridge
- Engines
- Cummins QSC-500's
Straight Drives
Why is the 340 susceptible? Is it the smallest shaft they put on the biggest gas engines? In other words, if you get a 360 or 380, do they come with the same 8.1 but bigger shafts? If you get a 320 or 300, maybe they have the same shafts as the 340 but smaller motors (99%) and they weigh less. Just brain storming. Otherwise, it would be a design feature, and I don't see that being the case. Are the struts mounted slightly out of line with the shaft due to hull shape? My 2 1/3 year old 340 needed Cutlass Bearings when I bought it. I know the engine/transmission assy is aligned to the bearings, but, just brain storming. Maybe the engine mounts are too weak for the 8.1's. Maybe the stringers are too soft.
- Oct 6, 2006
- 12,153
- Boat Info
- 1996 450DA
- Engines
- 3116 Caterpillars
I've got a theory ..........which is that the broken shafts are caused by misalignment.
The 340 uses a 1.50" diameter shaft, but the transmission ratio and props used require that the shafts be turned pretty fast. Any misalignment is going to be accentuated if you rotate them fast. The longer the unsupported distance is, the more whip a misaligned shaft is going to have. This is likely why we see some broken shafts on 340DA's but not on 320DA's.....i.e. the unsupported distance is less. By comparison, the 7.4L Mercruiser powered 390EC used 1.25" shafts that were longer than those used on the 340DA above and, I have never heard of a broken 390EC shaft.
Our dealer sold a bunch of 340DA's and there just isn't a problem with broken shafts, but I've seen several shafts replaced that show signs of significant wear due to misalignment. BUT, this dealer sold and services a lot of big boats. Shaft alignment is something they do regularly. Do we know if any of the broken shaft boats had regular shaft alignments?
Based on what I see from new boat buyers in our area, almost every one figures managing the maintenance on his boat is someone elses job. Generally, most just fix broke stuff and don't get concerned about preventitive items. Shaft alignment is simple and easy to do, but usually involves getting a technician to the boat, yet there isn't much that is as important to keeping the boat running smoothly as alignment.
Other points raised by others.......struts out of line? Not likely, unless the boat has indeed hit something. Sea Ray mounts the struts very precisely using a lazer sighting device by shimming from the bottom. Cutlass bearings usually fail because of shallow water operation in sandy conditions. A failure caused by misalignment will show extensive wear at one enn or the other ;top or bottom, but will be not unifomly worn throughout the length of the bearing. The shaft collar recommended by a dealer is really a good idea for all of us with room for them. It is a simple $5 item that goes on the shaft ahead of the strut and can easily save a $2000 prop, significant damage to the rudder and scramble city trying to shove a towell in the shaft log if you do lose a shaft.
I've owned my boat 12 years and we've checked the alignment 5 times.......#6 is scheduled next month. When was your last alignmant check?
The 340 uses a 1.50" diameter shaft, but the transmission ratio and props used require that the shafts be turned pretty fast. Any misalignment is going to be accentuated if you rotate them fast. The longer the unsupported distance is, the more whip a misaligned shaft is going to have. This is likely why we see some broken shafts on 340DA's but not on 320DA's.....i.e. the unsupported distance is less. By comparison, the 7.4L Mercruiser powered 390EC used 1.25" shafts that were longer than those used on the 340DA above and, I have never heard of a broken 390EC shaft.
Our dealer sold a bunch of 340DA's and there just isn't a problem with broken shafts, but I've seen several shafts replaced that show signs of significant wear due to misalignment. BUT, this dealer sold and services a lot of big boats. Shaft alignment is something they do regularly. Do we know if any of the broken shaft boats had regular shaft alignments?
Based on what I see from new boat buyers in our area, almost every one figures managing the maintenance on his boat is someone elses job. Generally, most just fix broke stuff and don't get concerned about preventitive items. Shaft alignment is simple and easy to do, but usually involves getting a technician to the boat, yet there isn't much that is as important to keeping the boat running smoothly as alignment.
Other points raised by others.......struts out of line? Not likely, unless the boat has indeed hit something. Sea Ray mounts the struts very precisely using a lazer sighting device by shimming from the bottom. Cutlass bearings usually fail because of shallow water operation in sandy conditions. A failure caused by misalignment will show extensive wear at one enn or the other ;top or bottom, but will be not unifomly worn throughout the length of the bearing. The shaft collar recommended by a dealer is really a good idea for all of us with room for them. It is a simple $5 item that goes on the shaft ahead of the strut and can easily save a $2000 prop, significant damage to the rudder and scramble city trying to shove a towell in the shaft log if you do lose a shaft.
I've owned my boat 12 years and we've checked the alignment 5 times.......#6 is scheduled next month. When was your last alignmant check?
islandhopper00
Active Member
That's a good theory Frank except, some of the owners say their shafts are breaking after 40-50 hours of operation. Along that line of thinking, one would have to have their shafts aligned every year, to every other year basically.
Ha, I just looked back and that's what you are reccomending. Jeeze, I thought there is less maint. with V-drives.
I would think Sea Ray would design a shaft support set up that would not allow so much whip, causing wear and misalignment.
Ha, I just looked back and that's what you are reccomending. Jeeze, I thought there is less maint. with V-drives.
I would think Sea Ray would design a shaft support set up that would not allow so much whip, causing wear and misalignment.
tobnpr
New Member
Shaft "support setup" doesn't cause the wear and misalignment. Shafts on a V-drive setup are as short as you can get, so whip that you might get from a long shaft without intermediate supports isn't relevant here.
Ever seen the shafts for a 70' sportfisher? Longer than your boat- and when properly installed with all components in alignment there are no issues.
I agree that misalignment is a likely cause, short of SR having a QC problem with the supplier of their shafts. Wonder if they use Aquamet? Or some Chinese knockoff...
As I stated way back in the beginning of the thread, I'd bet at least some of these failures are due to owners installing their own props not knowing the proper procedures involved.
fresh water
Banned
Factory defect?
islandhopper00
Active Member
Ah, that makes sense.
I always wondered how much the shafts deflect as the props hit disturbed water, or currents or come out of the water. I always suspected alot of stress at the prop.
- Nov 26, 2006
- 7,628
- Boat Info
- 2008 44 Sedan Bridge
- Engines
- Cummins QSC-500's
Straight Drives
I have learned that the alignment must be performed by the dealer after the boat has been splashed. Why do that? It costs time, money, and will decrease profits from maintenance. It's likely that my boat was not aligned on delivery to the PO. It was aligned immediately after I got it home. I'll have it checked this year.
islandhopper00
Active Member
Thinking about it, I was in the engineering dept in the navy. Not an engineer, a gas turbine technician. The shafts on the cruiser I was on are loonnnggg. I remember a spec about engine horsepower being limited due to shaft torque stresses.
Once we timed the rotation difference between engine end and hull penetration at nearly 1 1/2 turns differential. We staged a guy in shaft alley and at the reduction end. painted marks on the shaft and best we could tell at power there was 1 1/2 turns difference. It wasn't exact by any means but remarkable none the less.
Makes me wonder if small boats have this kinda torque on their shafts.
What do you think Frank. Just wondering.
Once we timed the rotation difference between engine end and hull penetration at nearly 1 1/2 turns differential. We staged a guy in shaft alley and at the reduction end. painted marks on the shaft and best we could tell at power there was 1 1/2 turns difference. It wasn't exact by any means but remarkable none the less.
Makes me wonder if small boats have this kinda torque on their shafts.
What do you think Frank. Just wondering.
Ryan
New Member
What is involved in alignment? I know it is a task left to a professional, but I would like to know what they are supposed to do, and how they do it...
- Oct 6, 2006
- 12,153
- Boat Info
- 1996 450DA
- Engines
- 3116 Caterpillars
I am of the opinion that as a boat settles, the shafts should be realigned. The factory aligns the shafts when the boat is new, it is then hauled a long distance on a trailer, or devlivered by water, and eventually launched. After resting on her own bottom for a minimum of a week, conventional wisdom is that the shafts should be re-aligned. I believe this step is often overlooked on new boats (but what do I know). After this second alignment, the boat should be good for 12 months when the 3rd alignment should be done. After that, every other year has proven sufficient for me on my own boat.
As far as the alignment procedure, it is really pretty simple and requires no special tools. However, it is one of those jobs you really need to see done before trying it. The coupler is unbolted and the halves separated then the distance between the coupler faces at 90, 180, 270 and 360 degrees is measured with a feeler gauge. Different diameter couplers have different tolerances. To change the coupler clearance means you have to loosen the engine mounts and raise/lower one or more of the 4 engine mounts to achieve the desired clearance, while keeping the bolt holes in alignment between th 2 halves. This is the "screw-up point" since a little goes a long way and it is easy to get the alignment in worse shape after you attempt the aignment that when you start.
Even if you hire the alignment done by the local dealer, if they have decent experience, both engines take less than an hour. Hardly enough to break the manitenance bank, and at once every other year, it doesn't come close to the cost of maintaining even single outdrive.
As far as the alignment procedure, it is really pretty simple and requires no special tools. However, it is one of those jobs you really need to see done before trying it. The coupler is unbolted and the halves separated then the distance between the coupler faces at 90, 180, 270 and 360 degrees is measured with a feeler gauge. Different diameter couplers have different tolerances. To change the coupler clearance means you have to loosen the engine mounts and raise/lower one or more of the 4 engine mounts to achieve the desired clearance, while keeping the bolt holes in alignment between th 2 halves. This is the "screw-up point" since a little goes a long way and it is easy to get the alignment in worse shape after you attempt the aignment that when you start.
Even if you hire the alignment done by the local dealer, if they have decent experience, both engines take less than an hour. Hardly enough to break the manitenance bank, and at once every other year, it doesn't come close to the cost of maintaining even single outdrive.
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