What makes stern drives unreliable?

[Jurgen]

Hats off to you if you do that amount of hours per year and not business related. Unfortunately for me work gets in the way..... And the cost of fuel....

Actually you've made me think about our usage. For the first few years we owned the boat we averaged around 180 hours a year, but since fuel prices have gone through the roof we're lucky to do 70 hours. Still use the boat as much, just differently.

Interesting, Our Sealine S37 is a 1997 boat and has just short of 1800 hrs, we do an average of 50 hrs a season but prior to our ownership she was used for occasional charter work so averaging hrs x year were about average, it's only her time as a charter boat that has pushed the hrs up.

Sorry thread drift I think mechanical issues can arise with any system, yes shafts may be more reliable & Out drives may cost more to repair but as mentioned by a previous contributor sometimes you wont have a choice of propulsion system. Maintenance is a basic, Shafts will eventually fail if not maintained i.e stern gland & lubrication etc just as Bellows can be fitted incorrectly to a Drive resulting in very costly repairs.

If we want to ensure that the oily bits do not cost us a small fortune then we must consider selling our souls to the Dark Forces of the Wind and become sailors, if the main engine on a yacht goes south it can be propelled with an out board.

 

[KevB]

The first 12 years of an outdrive's life should befairly trouble free, shouldn't they? The next 12 years could be VERY different. Good luck!

I've no reason to suspect they will not continue trouble free.
I hope your shafts stay in line with your engines. your P brackets stay attached to your boat, Your glands don't leak, your gearbox works as it should, your drive couplings don't wear and you don't get anything caught around your props requiring a lift or a diver. Oh, and most important... stay off the bottom.

Good luck.

 

[blueglass]

I've no reason to suspect they will not continue trouble free.
I hope your shafts stay in line with your engines. your P brackets stay attached to your boat, Your glands don't leak, your gearbox works as it should, your drive couplings don't wear and you don't get anything caught around your props requiring a lift or a diver. Oh, and most important... stay off the bottom.

Good luck.

all in line, p brackets attached, glands don't leak more than they should, gearbox and drive couplings all housed away from the cruel sea and doing fine. I AM a diver and also have a keel and can take the ground.
point taken however and agree nothing is ever guaranteed - just a game of going with the main chance which for me means shafts.

 

[Firefly625]

I think they're the devil's own work. The two sterndrive boats i've had have cost me big money in repairs despite annual servicing, and most people I know with them have also had issues. I think one problem is that small failures can cost so much to repair. I had some slight pitting around the drive shaft seal, and the solution was a new lower drive leg at over £3k! Shaftdrives on the other hand are virtually fit and forget, and i've not had a hint of an issue in 10 years of shaftdrive ownership.

It's often academic though, because on most sizes and types of boats you don't get the choice. If you want a 25-40 foot sport cruiser for instance, it's going to be on sterndrives.

All just IMHO... I wouldn't buy a boat with outdrives, its just the thought of all that precious machinery submerged in salt water... I just couldn't bear the thought..

But then I have never owned an outdrive boat so I am totally blinkered in my view... and I admit I would love the additional accommodation that sterndrives gives... but will never take the plunge.

 

[CX54WEK]

All just IMHO... I wouldn't buy a boat with outdrives, its just the thought of all that precious machinery submerged in salt water... I just couldn't bear the thought..

But then I have never owned an outdrive boat so I am totally blinkered in my view... and I admit I would love the additional accommodation that sterndrives gives... but will never take the plunge.

Touch wood and up until now our sterndrive has been totally reliable. Currently has about 1500 hours running time and is 10 years old. It has never needed more than an annual service.

The benefits far outweigh the additional maintenance costs to us, extra accomodation (which you need all you can get on a 25ft boat) the ability to change the props in the water, the ability to lift the drive to enter shallow water, the ability to take the ground and the extra effiicency.

At the end of the day if it all does go pear shaped then a recon VP DPE doesnt cost the earth.

 

[Peanuts]

As CX54WEK, my S28 is 11 years old, 1500 hrs + and apart from a couple of seal changes totally reliable. My thoughts are that we only hear about problem drives, just consider how many boats are out there with outdrives that are working OK, the problem ones are only a very small percentage - just my thoughts

 

[Scubadoo]

Same as KevB, had my boat since new (14years) and never had any trouble with my outdrive and that includes fishing line and ropes encounters. It is serviced every other year and checked annually. I have no reason to think they are nothing but trouble and would buy another boat with outdrives, nothing against shafts either, it really depends on the boat your buying at the time.

Maybe I am lucky, but I think it is more down to having a good maintenance company who do a thorough job (DB Marine), not brave enough to do it myself.

 

[Elessar]

IMHO shafts for anything over 30' are essential. The worse fuel usage is easily compensated by reduced maintenance costs, and better steerability of twin shafts.

Ok you CANNOT touch bottom with shafts without a subsequent haul out, whereas you could possibly change props on a out drive without a lift out.

VP have had major issues with the drives on the D6s, and access for seemingly simple tasks requires moving the engines forward on many boats using these.

They are better for fast planing boats because of the higher weight distribution towards the stern, but not conducive to stern cabins.

Out drives do have a certain star quality for catching errand continental quilts floating along the Hamble too ! Took three hours to dig the mess out from between the duo props on my pals Princess V42.

Not better steerability just different. So many people are taught to drive a sterndrive like a shaft drive, then find it difficult.

Changing, cleaning and clearing props in the water a huge benefit of drives.

And the ability to dry out on a sandy bottom. Lots of plus points.

 

[Firefly625]

...so what we can deduce from all this.....its just Gary that gives sterndrives a bad name!!!

 

[wipe_out]

My thoughts are that we only hear about problem drives, just consider how many boats are out there with outdrives that are working OK, the problem ones are only a very small percentage

I think that is a valid comment.. Statistically there are probably many times more stern drives than shaft drives in operation in the the recreational space, especially in the 25 - 50ft range that most of us fall into.. So the likelihood of hearing about issues with stern drives is probably far higher than hearing about issues with shafts simply because there are so few shaft based boats by comparison..

 

[gjgm]

I was going to say totally reliable but then I did have one explode underway. One almighty bang and it went through the casing.Not alot to repair on that one!

 

[Portofino]

Like others my VP DPG,s with Kad 300,s in a 12M boat have been trouble free, just routine service +
One U/J replaced at one bellows change ( € 80 part) ,and this year - boat 10 y old -I think the gearshift selectors or something ? was changed on other € 300 on top .
There,s one point nobody seems to have picked up on -is the performance , regarding higher cruising and max speed that outdrives seem to confer on a boat.
OK sports boats have a different image from say a Nelson or a Hardy,
But where I boat the Med the performance element is important to me .I like overtaking 22 knot flybridge slugs at 30 knots along with the general wind in your hair experiance ,with plenty in reserve -seen 40 knots on the GPS -lightley loaded with a clean bottom at Easter .
Also for me - I can also raise the legs -lay on the swim platform and easily reach down to clean/ scrape the props -usefull ,for me here in the Med.
Looking at the VP manual some 160000 of these DPG units were made 2001-2004ish .thats a lot .
So like someone has mentioned -number wise the silent majority are content ,but the 0.2% will winge and tell us all about thier woes?
I think I would miss the thrill of speed with shafts if we went larger , guess could look at Arnesons
"Jumping from frying pan to fire". hmm? Dunno?

 

[Greg2]

As CX54WEK, my S28 is 11 years old, 1500 hrs + and apart from a couple of seal changes totally reliable. My thoughts are that we only hear about problem drives, just consider how many boats are out there with outdrives that are working OK, the problem ones are only a very small percentage - just my thoughts

Not sure I buy that theory. Been around boats for some time and spent lots of time chatting with engineers.....those that have had no problems have been fortunate IMHO but long may it continue as I don't have an axe to grind here. i would have drives on the right boat and agree with all the benefits...... I just think that problems are an inevitability for many. Maintenance will reduce the risk but won't be an absolute guarantee

 

[Portofino]

Spot the shafts- this my stomping ground BTW
http://www.youtube.com/watch?v=4y69Gd6rIeo

 

[Nick_H]

Looking at the VP manual some 160000 of these DPG units were made 2001-2004ish .thats a lot .
So like someone has mentioned -number wise the silent majority are content ,but the 0.2% will winge and tell us all about thier woes? ?

Nice use of statistics! About half the responses say sterndrives are problematic, and you equate that to 0.2%, because there are 159,000 stern drive owners who don't post on here

There has been not a single report on this thread of a shaftdrive problem, but someone has concluded that is only because there's less of them! Brilliant!

 

[gjgm]

Nice use of statistics! About half the responses say sterndrives are problematic, and you equate that to 0.2%, because there are 159,000 stern drive owners who don't post on here

There has been not a single report on this thread of a shaftdrive problem, but someone has concluded that is only because there's less of them! Brilliant!

Well his stats might be questionable but when was the outdrive developed...late fifties?So there must be something going for it and maybe the running costs are higher

 

[volvopaul]

Nice use of statistics! About half the responses say sterndrives are problematic, and you equate that to 0.2%, because there are 159,000 stern drive owners who don't post on here

There has been not a single report on this thread of a shaftdrive problem, but someone has concluded that is only because there's less of them! Brilliant!

Nick , I mentioned one last week.

Phantom 43 , shaft shears off just rear of p bracket.,other shaft removed and tested with crack spray to find also cracked in key way area which meant further running would have meant another perfect prop at the bottom of the sea.

Some years ago fairline fitted the cat 3208, massive 10400 cc engine with loads of torque, propped right through 1 3/4 inch shafts resulted in the same problem the shaft snapping at the taper, the inertia was also that great it stalled the engine going from forward to reverse.

 

[GrahamHR]

Interesting, the comment about only one set of U/Js needing replacing. I did replace a set with genuine VP ones on a 1999 DPS, quite cheap. VP clearly didn't think they made enough money just supplying replacement parts or drives, so they designed the later DPS and DPSA drives with input shafts with U/Js that seem to be unavailable, so the whole input shaft assembly has to be replaced ; hundreds of pounds ( with re shimming etc in the upper drive unit by a VP dealer, so hundreds more I expect). The U/Js can actually be removed, but there is no reference I can find to replacement ones from Rockwell, the drive shaft supplier ! I can well imagine the discussion:

VP; Can you make us an input shaft where the U/Js are an unique non automotive size that no-one else makes?
Rockwell: Yes, as long as we get a sole supply position for X numbers of years/ units.
VP; OK, as long as you commit not to make the unique U/Js available
Rockwell; Deal.

 

[superheat6k]

Shafts are not trouble free, but when they go wrong it is a matter of degree of grief / cost to correct.

Had to replace the shaft in my last boat due to severe crevice corrosion where the prop was mounted close to the cutlass bearing.

This was not helped by the original shaft material. However, new 40mm shaft of duplex stainless, cutlass bearing, stern seal and 20" prop was less than £500. Not sure I could have changed an outdrive for that.

I for one will be sticking with shafts as an absolute must on any future boat.

 

[alruss]

stern drive reliability

My volvo 100 out drives are over forty years old, they get service every other year, oil checked regularly for water ingress and seals replaced when required. There is a picture of them, the props were replaced before she was re-floated. The hull is not bad for a 1968 build either. The drives are also working at the top of their power rating, they will probably fall apart now I have bragged about them.