Outdrives - a commercial perspective,

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kashurst

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Spent last week on Guernsey - very pretty but drove me mad after 3 days, probably better done by boat. However went on a trip around Sark and out lying rocks etc seal spotting (needed a boat fix)
The boat was a @35ft motor catamaran built specifically for the tourist/dive business. Got talking to the skipper about the boat. He was telling me he bought the boat new about 18 months ago and specced it with 200HP volvos per side with duo prop outdrives for economy. Its very economical it does 55 l/hour at @ 20 knots, well impressed. But....

As it's commercially used the outdrives have to be serviced and checked every 100 hours, he wore the first set of outdrives out after 1000 hours. He is finding the maintenance costs a problem and now regrets not speccing shaft drive even though it would use more fuel! I always thought that outdrives would be perfect for commercial use as the fuel savings would really kick in - apparently not. Anyone know the commercial situation for IPS
 
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kashurst said:
Spent last week on Guernsey - very pretty but drove me mad after 3 days, probably better done by boat. However went on a trip around Sark and out lying rocks etc seal spotting (needed a boat fix)
The boat was a @35ft motor catamaran built specifically for the tourist/dive business. Got talking to the skipper about the boat. He was telling me he bought the boat new about 18 months ago and specced it with 200HP volvos per side with duo prop outdrives for economy. Its very economical it does 55 l/hour at @ 20 knots, well impressed. But....

As it's commercially used the outdrives have to be serviced and checked every 100 hours, he wore the first set of outdrives out after 1000 hours. He is finding the maintenance costs a problem and now regrets not speccing shaft drive even though it would use more fuel! I always thought that outdrives would be perfect for commercial use as the fuel savings would really kick in - apparently not. Anyone know the commercial situation for IPS
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My feeling is there are only two choices: shaft drives or outboards, everything else has major reliability problems.

Shaft drive has a simple gearbox/cutlass rubber bearing...can't get simpler than that.
Outboard has also got a simple 90 deg bottom leg gearbox; and the latest lean-burn outboards exactly match diesel fuel burn.

Outdrives, Ips, sail drive, .....etc etc is far to complicated and fragile and expensive to maintain.
 
rustybarge said:
My feeling is there are only two choices: shaft drives or outboards, everything else has major reliability problems.

Shaft drive has a simple gearbox/cutlass rubber bearing...can't get simpler than that.
Outboard has also got a simple 90 deg bottom leg gearbox; and the latest lean-burn outboards exactly match diesel fuel burn.

Outdrives, Ips, sail drive, .....etc etc is far to complicated and fragile and expensive to maintain.
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Hate to say this as there are a lot if folk on here with outdrives, but I agree with your view 100%
 
Oh dear......another re-run of the shaft v drive debate.....and so soon after the last one! :-)

On a serious note we have recently bought a boat with drives at work and the 100 hours came round fairly swiftly. Next one will probably have jets
 
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kashurst said:
Anyone know the commercial situation for IPS
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No idea of how many of the things they actually sold for installation on commercial boats, but I bet that the number would be pretty close to zero, if it weren't for some pleasure boats which, being registered for charter, could theorically be considered commercial boats...
 
Has anybody ever seen a study/report into the efficiency of sterndrives over shafts before? I mean other than sales bumpf?
I would be quite interested (from a personal geeky perspective) to read the data.
In truth having studied as an Engineer at sea and having a decent understanding of Naval Architecture, I have a really sad love of all the little details of marine design. Try as I might though all I can find online is sales stuff from Volvo and other manufacturers. I could go to the library at the old Nautical College in Glasgow but I left there owing the library a couple of pound in late fees and I worry that by now my debt will be akin to that of Greece!
 
have you looked at some of the old MBY boat reports where they test similar boats, one with outdrives, one on shafts. I think there was one done on the sealine S43 possibly others
 
When in Ramsgate and Burnham recently,did notice one or two fast charter type boats with outdrives,however they may possibly have been water jets.
IPS does not appear to have caught on for smaller commercial boats,not sure if its the initial costs or if people do not want a lot of unprotected aluminium dangling underneath especially if used anywhere close inshore or shallow harbours.
 
kashurst said:
Spent last week on Guernsey - very pretty but drove me mad after 3 days, probably better done by boat. However went on a trip around Sark and out lying rocks etc seal spotting (needed a boat fix)
The boat was a @35ft motor catamaran built specifically for the tourist/dive business. Got talking to the skipper about the boat. He was telling me he bought the boat new about 18 months ago and specced it with 200HP volvos per side with duo prop outdrives for economy. Its very economical it does 55 l/hour at @ 20 knots, well impressed. But....


As it's commercially used the outdrives have to be serviced and checked every 100 hours, he wore the first set of outdrives out after 1000 hours. He is finding the maintenance costs a problem and now regrets not speccing shaft drive even though it would use more fuel! I always thought that outdrives would be perfect for commercial use as the fuel savings would really kick in - apparently not. Anyone know the commercial situation for IPS
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As you say, a commercial perpspective, perhaps. 1000hours is going to be alot of years on most leisure boats. And several owners.
 
oldgit said:
When in Ramsgate and Burnham recently,did notice one or two fast charter type boats with outdrives,however they may possibly have been water jets.
IPS does not appear to have caught on for smaller commercial boats,not sure if its the initial costs or if people do not want a lot of unprotected aluminium dangling underneath especially if used anywhere close inshore or shallow harbours.
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As far as i remember IPS is designed to shear off if it makes contact with a solid object, so that it won't rip out the bottom out of the boat; more sofisticated than with saildrive which will leave a gaping hole in the hull. Outboards will kick up out of the water; and because the shaft drive propellor Shaft is nearly horizontal it will tend to hop over obstructions, maybe giving the prop a bit of a bang. 'P' brackets will be pushed up rather than ripped off because the shaft protects them from a sideways blow.

The biggest advantage of an O/B has to be tilting it completely out of the water......no salt water corrosion or fouling to worry about. That must add up to considerable savings over the years.
 
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I don't think its a case of either outdrive or shaftdrive. For sub 35ft boats, shaftdrive isn't really viable because the engine is further forward and eats up too much accommodation space (yes I know there are some sub 35ft boats with shaftdrive but they are heavily compromised on accommodation). In fact thats one of the major reasons why outdrives have been so successful; it has allowed boat builders to offer far more accommodation in smaller boats than they could have dreamt of with a shaftdrive installation. The other reasons of course are ease of installation and superior performance/efficiency. Effectively what outdrives have done is to open up the whole small boat market to a new type of customer, the weekend boater who buys a boat for fun rather than work. In fact I'd be willing to bet that most boaters on this forum had an outdrive powered boat as a first boat. Yup its easy to criticise outdrives for higher maintenance costs and, arguably, more difficult slow speed handling but without outdrives, I bet many of us would never have got into boating
 
Deleted User said:
I don't think its a case of either outdrive or shaftdrive. For sub 35ft boats, shaftdrive isn't really viable because the engine is further forward and eats up too much accommodation space (yes I know there are some sub 35ft boats with shaftdrive but they are heavily compromised on accommodation). In fact thats one of the major reasons why outdrives have been so successful; it has allowed boat builders to offer far more accommodation in smaller boats than they could have dreamt of with a shaftdrive installation. The other reasons of course are ease of installation and superior performance/efficiency. Effectively what outdrives have done is to open up the whole small boat market to a new type of customer, the weekend boater who buys a boat for fun rather than work. In fact I'd be willing to bet that most boaters on this forum had an outdrive powered boat as a first boat. Yup its easy to criticise outdrives for higher maintenance costs and, arguably, more difficult slow speed handling but without outdrives, I bet many of us would never have got into boating
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I'd agree; but don't forget the shaft drive angling boats : Merry fisher 7 mtr, and The Arvor 215 both diesel shaft drive. And what about the fabulous Antares 7.60 shaft drive?
 
rustybarge said:
I'd agree; but don't forget the shaft drive angling boats : Merry fisher 7 mtr, and The Arvor 215 both diesel shaft drive. And what about the fabulous Antares 7.60 shaft drive?
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Yeah they're good boats but that really illustrates the point. They're aimed primarily at the boater who likes to do a bit of fishing. Most boaters buy a boat in which they have to accommodate family and friends and thats where outdrive boats really score
 
Deleted User said:
Yeah they're good boats but that really illustrates the point. They're aimed primarily at the boater who likes to do a bit of fishing. Most boaters buy a boat in which they have to accommodate family and friends and thats where outdrive boats really score
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Hardy 32.
Princess 30 ds.

Err,....?

The engines fit under the wheelhouse floor on a shaft drive: suits hardtops and aft cabins quite well?
And all modern boats have self draining cockpits which are above the waterline anyway, which gives a flat floor between the cockpit and saloon.
 
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Just about every family boat built before the diabolical invention of Satanic devices had shaft(s)
Broom.Suspect inch for inch the internal accomodation on a Broom 35 will prove more useful than any of its much newer rival....example of a successful aft cabin outdrive boat would be interesting
Profile 33
Any Seamaster you care to mention.
Anything Steel or Dutch
Sub 35ft Hardys.
Colvic.
Cleopatra.
Tremlett.
Moonraker
Princess 30DS/32.33
Fairline Corniche
Birchwood
Freeman.
RLM.
All of them no doubt accomodated family and friends over the years. :)
 
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I've learned the hard way to keep as much money out of the water as possible! So to me, if she lives in the water, its shaft drive every time. I love stern drive & duo-prop, its a hyper efficient drive, but to keep it that way you absolutely must stay on top with maintenance. A rebuild after 1,000 hrs commercial service didn't sound too bad to me, be interesting to compare the cost & aggravation of that with fuel savings though.
 
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