Twin diesel vs twin petrol conundrum...

oldgit said:
Small petrol boats do not go very far or run up any serious hours .......

"our leg has yet to drop off".....Give it time give it time .. :)
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I don't agree that they're all going to fail, It's all down to maintenance and looked after they perform well and are reliable. As I now find myself lucky enough to be working in a boatyard, I've come to the realisation that there are way more cutlass bearing and seals replaced than I ever imagined! These jobs are also costly when paying professionals - especially if shafts have to be removed.

I've also been very surprised by the number of people buying boats that have no idea on either the mechanical workings nor the servicing required! I guess that's true of cars too now with a surprising number of people who have no idea how to check oil or who think the annual MoT constitutes a service... Some owners who have had boats for years run drives for 3 years without servicing - just annual lift, antifoul and back in! Then there's those that don't lift for 2 years - or until the jungle hanging off the bottom prohibits the boats from moving. :ambivalence: Drives are fine if looked after - taking shortcuts with such things is like playing Russian roulette...

Edit: I should add that if everyone serviced themselves at least once, they'd have a better idea of how they work, why service is needed and also why engineers charge what they do! ;)
 
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CX54WEK said:
Can't agree with a lot of that.

We have had our little diesel engined boat for 9 years now and have taken her far and wide, far further and wider then some with much bigger boats will ever dream of. The size of the boat needn't limit your enjoyment of it. We comfortably stay aboard for two and three weeks at a time, which is all that work allows us for now.

Despite all of the dire warnings from yourself, our leg has yet to drop off, self combust or sink the boat.
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I agree with the distance thing - we've been far further in our 16' Fletcher than many of the much bigger floating caravans in the local Marinas! Much of this is down to confidence and reading the conditions however rather than the boat itself. (That said, I have gone out in F5 for safety/marshalling when I wouldn't have dreamt of taking the family out! :ambivalence:)
 
rbcoomer said:
I don't agree that they're all going to fail, It's all down to maintenance
Some owners who have had boats for years run drives for 3 years without servicing -
;)
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I have never forgotten my first service in 1976. My boat was brand new the year before and I had the first service to comply with the warranty, with twin Volvo outdrives and less than 100 hours, the engineer said "I managed to save your outdrive leg" I seem to remember that a fisherman's nylon line had damaged the oil seal and water was in the outdrive leg gearbox.
 
I know a shaft drive boat that just gently brushed an underwater object hardly marked the prop yet pulled the shaft out and cracked the bellhousing like an egg which lost drive . It nearly sank the boat . Later found also to have damaged the gearbox. I know this as I assisted in its rescue .
Getting off my fully floating boat onto one that was sinking with a female crew screaming and the usually calm skipper understandably in panic mode was an interesting experience.
Bellhousing and gearbox cost much the same as a new outdrive , if not more . Had it been an out drive the props would probably have been trashed but the leg would have kicked up without much damage.
 
Jim@sea said:
I have never forgotten my first service in 1976. My boat was brand new the year before and I had the first service to comply with the warranty, with twin Volvo outdrives and less than 100 hours, the engineer said "I managed to save your outdrive leg" I seem to remember that a fisherman's nylon line had damaged the oil seal and water was in the outdrive leg gearbox.
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Pretty common occurance.
 
CX54WEK said:
Pretty common occurance.
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Yes it is, and I suspect the engineer's comment was more to big himself up than anything else. I doubt he did much more than change the oil and the oil seal.
If I am mistaken, and he removed the outdrive, took it back to his workshop, stripped it down and replaced various internal gears and components I apologise. :D
 
Just to conclude the story, we agreed a deal today on a Portofino 25. Single 246hp turbocharged Steyr DIESEL :) After a lot of deliberation, we decided that we would plough more funds into the bricks and mortar and less into boat maintenance! Thus the twin engined 31's are something perhaps for the future. We feel that for now, the much reduced costs of a single engine and drive to service, plus having a trailer and being to pull out for maintenance myself made the 25 a better bet. We don't often need space for more than 3/4 persons, so this provides ample accommodation. The boat needs a service and some of the coloured gel has been hand painted so a few things to do, but overall an exceptionally well maintained boat and aside of the diesel repower, very original. Not picking up for a few weeks, but will do a new post when we have.
 
Regarding petrol boats and catching fire. A few years ago (40) I took my 26ft Petrol Cabin Cruiser across the Irish Sea to a small port on the Irish Coast. (used 30 gallons) tied up against a wall and started to fill the tank from jerry cans, The petrol filler was on the gunnel. as I was pouring the petrol into a funnel the local boatman came alongside my boat asking if I needed any help.
He grabbed the guardrail adjacent to where I was pouring, his hand was perhaps 18 inches from the poured petrol. His hand was holding a lit cigarette. I had to tell him twice "This is petrol" before he removed his hand.
 
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I love posts like this and hearing lots of like minded, passionate boating folks opinions. Just two things to add...

Firstly, I'm glad you got a boat that suits you...that is surely what it's all about, after all !

Secondly, there are great argument for both shaft drive and outdrive propulsions, as we all surely know...horses for courses, as an old marine engineering lecturer used to preach to me as a young scholar !

I love the shaft drive simplicity and realistically, beyond a certain size of boat (usually 34-37ft) the only real and general purpose option (with the exception of crazy performance boats). Simply due to the space afforded by such boats, manoeuvrability and many other common sense reasons...less components, simpler maintenance and the lovely balanced, surefooted handling and tracking they offer. They aren't without their down sides though. In use in a planing hull, the props are often the lowest and most exposed part of the boat...and without the ability to raise or lower...certain (and perhaps not relevant to some) applications are not permitted.

Outdrive no doubt have a higher efficiency over the shaft drive and are generally capable of higher speeds and more fuel efficient running, when compared to a similar application in shaft drive form. They also afford the smaller boat to have incredible power in a compact package.
On the other hand, they let them self down when it comes to manouveres, handling and general service cost...not to mention when they go wrong.
Just a few of many for and against for both apps. Like the old lecturer used to say...horses for courses...perhaps to add to this...each to their own.
 
Did it blow up Jim ?
Only joking. I would have crapped myself. Probably more likely the jerry can would have caught, rather than the boat though ?
 
I would agree with almost all that has been said about outdrives, apart from the parking bit.

If you have two sets of props, then props where you can vector the thrust are generally going to be easier to park than those where you rely on water going over rudders in the right direction, so long as the boat isn't too long and pointy.

The problems arise where it's a long boat with the drives close together, compared to something shorter and fatter with the props more underneath the boat.
 
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