Diesel Conversion Viability

[gsturgeon]

It's been a general theme of this forum that diesel is the way to go, so I decided to have a look at converting my twin 220 hp petrols.

Armed with the prices quoted in MMB for D4's I built a spreadsheet with all the variables I could think of to find the payback time.

I have assumed figures that seem reasonable for my use and the results show a payback in the case of fuel with 60:40 split at 29 yrs and more likely in the future, without a split, at 46 yrs

The assumptions made were that the conversion wouldn't add to the value of the boat - the engines and boat would be very old by then, and that the conversion labour would be funded by the salvage of the petrols. The 10mph speed is due to transiting harbours, rivers, locks and marinas, my normal cruise is 20 odd kts and that diesel/petrol consumption is in the ratio 5:8. no idea of the future cost of fuel or the effect of inflation, so I ignored them.

The only way I can get any reasonable payback time ie.within the boats lifetime, is to increase the annual hours to very high values (for me) which would generate spectacular fuel costs.

I am sure I have done something wrong, but what?

 

[Latestarter1]

Out of interest how much were quoted prices for D4's?

 

[neale]

It very rarely makes financial sense to swap petrol for diesel using brand new engines. Having said that for me it wasn't all about the money. Fuel availability, extended range and, dare I say, even safety implications.

Other points. You WILL definitely recoup some money on resale. Diesel boats always fetch more money than the same model with petrol engines. How much though is difficult to say but it won't be anywhere near the initial outlay. In a boat like yours it might be somewhere between £5 and £10k.

I also think your new MPG is a little out. I would suggest that a 30 footer with twin diesels on outdrives will deliver more like 2.5mpg on average. That is what I am getting with mine.

 

[DAKA]

It's been a general theme of this forum that diesel is the way to go, so I decided to have a look at converting my twin 220 hp petrols.

Armed with the prices quoted in MMB for D4's I built a spreadsheet with all the variables I could think of to find the payback time.

I have assumed figures that seem reasonable for my use and the results show a payback in the case of fuel with 60:40 split at 29 yrs and more likely in the future, without a split, at 46 yrs

The assumptions made were that the conversion wouldn't add to the value of the boat - the engines and boat would be very old by then, and that the conversion labour would be funded by the salvage of the petrols. The 10mph speed is due to transiting harbours, rivers, locks and marinas, my normal cruise is 20 odd kts and that diesel/petrol consumption is in the ratio 5:8. no idea of the future cost of fuel or the effect of inflation, so I ignored them.

The only way I can get any reasonable payback time ie.within the boats lifetime, is to increase the annual hours to very high values (for me) which would generate spectacular fuel costs.

I am sure I have done something wrong, but what?

Interesting figures, thanks for posting

I would look at selling your petrol boat and buying a diesel one like this for £14.5 k*

or this for £37k*

I dont know how old your boat is but I know of a recent year 2000 petrol 3055 selling for £25k


The additional cost is vastly reduced and an amount that should be returned when you have finished with it (assuming you don't loose the VAT receipt ).

Cost wise on paper it will not make sense, it isnt until you have lived with both that you appreciate the real value of diesel engines.

* adjusted figures for likely sale values.

 

[gsturgeon]

Bayliner replacement

£25k for a 3055, very depressing!

Bayliner's names are a bit misleading, I believe they don't include the bathing platform so the true length is nearly 33ft and an 11+ foot beam. With twin engines it does seem quite a bargain for someone.

The boats suggested are much smaller and only have one engine, I don't think my wife would be very happy on either score!

The cost of new boats seem to rise each year as the quality improves and now I just can't justify spending £200k on a hobby. So I was wondering about the cost of upgrading the one I have but it would seem that the diesel option is a non starter. It is a pity that LPG didn't take off as on a previous boat, I just about broke even when I sold it after three years.

 

[gsturgeon]

Engine prices

Out of interest how much were quoted prices for D4's?

I used the engine prices in the current MBM article, which are presumably list.

 

[gsturgeon]

I also think your new MPG is a little out. I would suggest that a 30 footer with twin diesels on outdrives will deliver more like 2.5mpg on average. That is what I am getting with mine.

I just based it on the ratio which seems to be a rule of thumb that the ratio between diesel and petrol consumption is approx 5:8. This seems to hold true with my two cars.

The 3055 is a beamy 33 footer with a misleading name!

I tried putting 2.5 in the spreadsheet but it still gave 24 years payback for 60:40

 

[neale]

I just based it on the ratio which seems to be a rule of thumb that the ratio between diesel and petrol consumption is approx 5:8. This seems to hold true with my two cars.

The 3055 is a beamy 33 footer with a misleading name!

I tried putting 2.5 in the spreadsheet but it still gave 24 years payback for 60:40

Like I say, it rarely makes financial sense.

How much do you think you would get for your boat now, compared to how much the same model with twin diesels are currently fetching?

I am guessing a difference of around £10k and if you assume you'll get an extra £5k when you sell it, your break even point becomes around 2 years at 2.5mpg or 2.5 years at your original figure.

So sell your boat and buy a diesel version. It's the only way that makes sense.

 

[gsturgeon]

Like I say, it rarely makes financial sense.

How much do you think you would get for your boat now, compared to how much the same model with twin diesels are currently fetching?

I am guessing a difference of around £10k and if you assume you'll get an extra £5k when you sell it, your break even point becomes around 2 years at 2.5mpg or 2.5 years at your original figure.

So sell your boat and buy a diesel version. It's the only way that makes sense.

I don't understand this, if it costs over £50k to convert and it raises the value of my boat by 10k, how can I recover a net cost of £40k by saving £1350 a year for 2.5 years?

 

[neale]

I don't understand this, if it costs over £50k to convert and it raises the value of my boat by 10k, how can I recover a net cost of £40k by saving £1350 a year for 2.5 years?

I think you need to re-read my post. You do not convert your existing boat. You sell it, add another £10k to the proceeds and buy one with diesels already in it.

 

[gsturgeon]

Woops

I think you need to re-read my post. You do not convert your existing boat. You sell it, add another £10k to the proceeds and buy one with diesels already in it.

Sorry Neil, I said I didn't understand! you are obviously right here.

I was looking at modifying my boat as I have invested a lot of money and effort in upgrades already. I didn't want to start again.

 

[neale]

If you definitely want to keep the boat you have you really have three options:

1. Leave it as it is and spend a couple of grand a year more on fuel
2. Buy two new engines but accept that you will NEVER get anywhere near the money back.
3. Try and source 2 good second hand diesels which are as rare as hens teeth and will still cost you a significant amount of money.

In your position I think I would be looking at option 1, and this is coming from someone who faced the exact same dilemma and chose option 2

 

[pappaecho]

I suspect that the only way you can make any real sense of it is to use the existing gearbox ans shaft + propellor.

So the real question is why diesel engines will fit the gearbox, and can you get a rebuilt lump for sensible money. Then you still have to marinise the engine with water cooled exhaust, and fresh to salt water heat exchanger.

I suspect the you may have to bit the bullet and stick with petrol.

That said my 1979 Princess, was fitted with dual Volvo petrol engines, which was replaced with two new twin Ford Mermaids in 1982.
There is still a solitary coil (Lucas) on the bulkhead between the two engines

 

[neale]

I suspect that the only way you can make any real sense of it is to use the existing gearbox ans shaft + propellor.

This boat has outdrives. The gear ratios will probably be wrong for a diesel and the drives themselves may not be up to the increased torque.

 

[Bandit]

The D4 is a good but heavy engine you would probably find a pair of D3's say 200 or 220 hp will perform as well , save you a bit of money and save 560kg for a pair.

For a fuel consumption comparison the best way is to talk to someone who has a similar sized boat to yours with diesels and ask them what they burn per mile, the difference will be marked.

You will sell the boat for more with diesels than petrols but not enough to justify the difference.

There is some value in your old engines and drives when sold together, perhaps 4k.

Dont buy a bobtail engine and use an existing drive they wont be matched, an engine and drive package is discounted compared with buying the engine and drive seperately and an older "petrol" drive sand gear ratio will not handle the torque.

I doubt however it will be justified as a business case.

You would probably be better to sell the Bayliner as it is and buy say a Fairline 33/35 with a good pair of AD41p 200 hp each.

 

[DAKA]

I was looking at modifying my boat as I have invested a lot of money and effort in upgrades already. I didn't want to start again.

I was in the same position a few years ago, I had a nearly new bayliner exactly how I wanted it after spending several years fitting extras.

I bought a much older diesel boat that hadnt been well cared for (acceptable but only just).

Even though at the time I thought the bayliner was a great boat it wasnt until I owned a British diesel boat I realized what everyone had been telling me.

The older British diesel boat was 100x better than the bayliner.

You could get another bayliner (diesel) but really If you want to move forward you have to let the Binliner go, its introduced you to boating at relatively modest outlay, got you hooked and before it starts to stifle your future boating enjoyment best let it go .

 

[Latestarter1]

New engines in old boats makes little sense to me particularly if people talking Volvo Penta.

VP sell heavily discounted engines to builders in order to build healthy aftermarket which is where they make their $$. However to Joe public prices are not on this planet! Never any point considering any VP motor for a one off installation such as a re-power. Another issue used to be the SIX MONTHS warranty nausia with repowers.

As to use of D3 cannot consider this a proper marine engine after what I have seen lately.

Kind of crosses over with parrallel thread on re-powering. People have been asking me for ages and in response I have been working on marine conversion of Cummins B engines out of DAF trucks for over a year. 180/220/260 Hp with the 180/220 ratings being turbo charged only, no pesky charge air coolers. Doing final dyno work on the 220 rating at the moment, none of your pansy/wishful Perkins Sabre 225 Hp either, 220 honest Hp.

These will be a professional job and any capable owner can have a pair of real robust mechanical marine engines for around 10K depending on what engines they are replacing.

 

[neale]

Another issue used to be the SIX MONTHS warranty nausia with repowers.

On my VP re-power I was given the standard 1 year warrenty with second year extension option.

 

[Latestarter1]

On my VP re-power I was given the standard 1 year warrenty with second year extension option.

Was repower done by VP dealer?

 

[ARA]

As to use of D3 cannot consider this a proper marine engine after what I have seen lately.

I have just repowered to D3-170 & have a standard 1 year warranty with a second option like neale. This was done by a VP dealer.

What have you seen lately on the D3's then Latestarter1 ?