Diesel good v petrol bad

[coliholic]

Re: Diesel Mirage

Some good ideas there Nick. I'll put my order in now for one of your new boats then.

Are vee drives a good idea though? What's wrong with outdrives on a boat this size? Oh and the aft cabin version was only a single small BMC 1.8ish diesel or petrol, didn't do twin installation as far as I'm aware, don't think there would be room in the aft cabin version for twins. I'm sure I've heard of one fitted with the 41's, though I bet it was bit tight in the engine room. Don't know if they moved the tank or how they gottem in.

Maybe get John Bennet to redesign and update, cos presumably he holds the copyright or whatever on it so would have to be involved. Maybe Fairline's still got the old moulds and would be prepared to do a deal.

Sounds as if you've got it all worked out. Surely you can get some kind of grant from the Highlands and Islands Development Board or whatever it's called to set up new industry in Scotland? Bit of re-training (more grants) and a subsidy from Brussels and who knows, "this time next year you could be a millionaire".

 

[Guest]

Re: Diesel Mirage

I'm not sure there are any millionaires in the boating business, at least not at that end of the market.

As far as outdrives go

a) It makes absolutely no sense to dangle an expensive marine gearbox in salt water permanently.
b) My 280's cost me a regular £1000 per season (at 80's prices), despite religiously replacing bellows/anodes, etc each year and all other recommended maintenance
c) Shaft drive boats handle better and close quarters maneuvering in the the Mirage was a nightmare in any kind of wind as the bow had a mind of its own and would blow about all over the place.
d) yours with diesels is better but the petrol engines I had, had a habit of stalling all the time when they were cold which invariably meant when reversing out of that tight spot in the marina (with an audience usually).

Anyway, much as I like boats, I don't think I would want to be in the business but I still think there would be a market for this size and layout of boat. Entry level craft for most of the big manufacturers are either too big or are that sort of overgrown speedboat type - all dash about and no accommodation. The only manufacturer who does something along these lines that I can think of is Hardy.

Nick

 

[Scubadoo]

Re: Diesel Mirage

Hi Nick,

Apart from Hardy, Sealine are still in there with the smaller accommondation type craft (24ft & 28ft).

By the way, why did it cost £1000 per season for the outdrive(s)?

RM.

 

[Guest]

Smaller craft

Sealine only do sportsboats in the smaller range and a sportsboat is fundamentally unsuited to the West of Scotland most of the time and, I would guess, the rest of the UK except for the three days of summer. I was really referring to boats with either an enclosed wheelhouse or, at least, a solid wheelhouse shelter such as the Hardy's, Seawards, Fairline Mirage, Princess 32. Although these are somewhat old fashioned, they are much more practical boats for our climate.

Re my outdrives, I had the boat for 4 seasons

Season one - fishing line around the prop, destroys seal but with no indication that anything is wrong until grinding sounds in drive - lower gearbox rebuild
Season two- starboard universal joint failure as a result of failure of Volvo bellows fitted two months earlier.
Season three - starboard clutch failure, characterised by engine racing whilst under way and then re-engaging with horrendous clunk
Season four - port clutch failure.

Season five - enoughs enough and replaced with shaft drive boat which I had for ten years and not once did I have any stern gear repairs required. As it happens the diesel engines were also far more reliable than the petrols.

Nick

 

[Scubadoo]

Re: Smaller craft

Thanks for that, sorry my mistake I did not realise you meant a solid wheelhouse shelter. I tend to agree with you about Scotland, when I'm diving in Oban we use a 30ft+ Rib with no protection - and I know how cold that is!

You seemed to had bad luck with outdrives, I don't think everyone has been through that expense regularly.

RM.

 

[adarcy]

Oldgit

Accepting the risk/problem of glazing a new diesel engine is past, then a diesel is much more economical than petrol at low throttle settings eg creepy crawly river work. Coliholic is being fair when he says 40% difference overall because it is about 15-20% at WOT but nearly 100% at/above idle. A petrol is sucking against an almost closed butterfly = churning losses and is usually running richer than stochiometric to avoid hiccoughs whereas a diesel has no air intake restriction but only meters the fuel. So with XS air and little fuel and long "burn time" due to low piston speed == v good combustion. Effectively, once it's run in properly a diesel is vmb for low power use and less need to blast it to "clear out the plugs"

Re engine life, what I took from the dieselpower website was a (justifiable I think) concern that v long diesel engine life is from old low stressed motors whereas most new turboDs may be as highly stressed as petrols were/are and the spare parts are more expensive.

Anthony