Diesel Heating Questions...

[David2452]

I can point you in the direction of a place you can buy flexible 80mm & 100mm duct in ali at about £15 for 3m http://www.ductstore.co.uk/acatalog/Semi-rigid_Aluminium_Flexible.html, the 60mm is more difficult to source cheaply but the Mikuni website is as good as any for the proper APK stuff. I am not really geared up for mail order on the stuff as packing and shipping takes up a lot of time and I am always busy with service and install work, but I do thank you for the kind thought.

 

[Whopper]

Is this an inboard out drive boat? If so why a diesel heater? My mastercraft is petrol inboard with a blow air heater attached to the engine. Can something similar not be fitted if it is an inboard?

 

[maby]

Is this an inboard out drive boat? If so why a diesel heater? My mastercraft is petrol inboard with a blow air heater attached to the engine. Can something similar not be fitted if it is an inboard?

Surely that depends on your pattern of usage - heating drawn off the engine is fine if you don't intend to ba aboard for long while stationary. it would be pretty uneconomical to leave the engine running for hours simply to heat the boat - and not very good for the engine.

 

[rbcoomer]

I can point you in the direction of a place you can buy flexible 80mm & 100mm duct in ali at about £15 for 3m http://www.ductstore.co.uk/acatalog/Semi-rigid_Aluminium_Flexible.html, the 60mm is more difficult to source cheaply but the Mikuni website is as good as any for the proper APK stuff. I am not really geared up for mail order on the stuff as packing and shipping takes up a lot of time and I am always busy with service and install work, but I do thank you for the kind thought.

Thanks - much appreciated and understand re postage etc :encouragement:

 

[rbcoomer]

Is this an inboard out drive boat? If so why a diesel heater? My mastercraft is petrol inboard with a blow air heater attached to the engine. Can something similar not be fitted if it is an inboard?

V8 Petrol inboard...

Surely that depends on your pattern of usage - heating drawn off the engine is fine if you don't intend to ba aboard for long while stationary. it would be pretty uneconomical to leave the engine running for hours simply to heat the boat - and not very good for the engine.

Agreed - perhaps ok when underway, but that's when we're most likely to have canvas down. Unlike a car, the engine's also at the wrong end and whilst a closed cooling/heater system is obviously possible, I envisage to be inefficient - too hot in the summer and cold when not underway in the winter. If we are using the heating when underway, it's not likely to be at WOT and more likely trolling along on tickover - i.e not much heat

 

[David2452]

Just reading your OP again and if the boat is petrol I counsel great care with the install and also noticed you mentioned three closeable vents, one vent should be of the always open style as if they all get accidentally closed it can lead to overheating of the unit with possible damage. I have a short PDF with advice for installing on petrol boats, if you would like a copy drop me a PM.

 

[Actionmat]

Keep your main pipe run as straight as possible with plenty of support so it doesn't sag. Give the heater the option of recirculating, use the sweeping 'T' joining pieces to run one or two extra vents (making sure one is the permanently open type) and wrap the lot in thermal foil lined bubble wrap insulation (thermawrap), two layers if possible. I've got a D2 on a 31ft boat installed this was and it's toasty at below zero. A huge improvement in the way it ran before insulating the pipes (Although it did use to heat the lockers up on its way to the vents). Good luck!

 

[rbcoomer]

Just reading your OP again and if the boat is petrol I counsel great care with the install and also noticed you mentioned three closeable vents, one vent should be of the always open style as if they all get accidentally closed it can lead to overheating of the unit with possible damage.

Thanks - LJS mentioned the non-closable vent above. Hadn't thought of that, but will certainly do.

Yes, petrol V8. There were two 'compartments' either side of the engine bay originally and I aim to replicate this as part of the rebuild. The port side housed the battery and the thinking was to divide this in two with the forward section housing the heater and the rear, two batteries. The starboard side was going to house an auxiliary outboard & fenders etc. I planned to fit a second bilge blower to the compartment that houses the heater and vent the exhaust via the battery bay out through the stern. The original bilge blower exited facing forwards above the engine bay along the rear of the padded sunlounger/engine cover. The plan is to route that out the stern too - i.e. outside of the canvas cover. I'll implement separate fire suppression/fuel cut-off for the heater compartment to the main engine bay.

 

[rbcoomer]

Keep your main pipe run as straight as possible with plenty of support so it doesn't sag. Give the heater the option of recirculating, use the sweeping 'T' joining pieces to run one or two extra vents (making sure one is the permanently open type) and wrap the lot in thermal foil lined bubble wrap insulation (thermawrap), two layers if possible. I've got a D2 on a 31ft boat installed this was and it's toasty at below zero. A huge improvement in the way it ran before insulating the pipes (Although it did use to heat the lockers up on its way to the vents). Good luck!

Thanks - all taken on board! The sagging shouldn't be a problem as it will be packed in under the floor - the only real option - so won't be able to move!

 

[blobby47]

Hi Folks

had a d2 in 22ft freeman,fed main cabin area 1 outlet, most disappointed with heat output. Circa 1800watts, only any good with cabin door closed and not to cold outside.
have a d4 in my princess 30, 2 outlets and stat controlled much better and good on diesel.
cheers bob

 

[Whopper]

By engine at the wrong end I take it you mean the back? Mine is rear engined v-drive and the heater has two outlets which are more than adequate on cooler days during the spring to autumn months (without canvas and after water sports i.e. proper cold). Under canvas I wold estimate them to have at least 70% of the heating capacity of the eber system on my fathers broom 38 cl. I've no idea the cost of diesel fired systems and while I agree they are superior for periods while a boat is stationary I think they are perhaps overkill on an open 21 footer. You could well save yourself time and money looking at a system based off the cooling system.

 

[Greg2]

I am just about to install a heat exchanger to our Broom to heat the cockpit and de-mist the windscreen. Got ours cheap but been speaking with JPC at Brundall and he indicated that they are around £300 ish new so not a bad option for heat whilst underway (Tom at JPC is a very helpful guy and they have an online shop).

Alongside this I have been looking to improve the performance of our Ebby and insulating the ducting seems to be a good move, as others have already indicated. Some cite 50% improvement and having experienced how hot the long run to our aft cabin gets I can see how reducing heat loss will be a benefit.

If you need heat whilst stationary then diesel fired is the way to go. If not then I think a heat exchanger will do the job for half the price, even at low speeds.

 

[blobby47]

Hi Folks
Just my experiences (now retired Engineer) 2 years ago bought a nice Birchwood 25 watermota (ford petrol. river cruiser but no hot water, or heating)

I fitted a 20 litre calorifier, cabin blower heater matrix unit, and a diesel powered webasto c top 5 kw water heater/boiler, as it turned out a great system no large ducting,very hot water from cold in 10/15 minutes and cabin heating within 2 minutes of unit starting, quiet and economical average diesel consumption less than .1/2 litre /hour.
used heater units from rover 75 s or early Freelander's on e bay around £120 mark, don't buy others used as use can bus systems on the cars and not suitable for general basic easy controls. Have fitted or overseen several similar used unit installations for pals at my marina since without many problems .this system can be used cruising or moored up
But BEWARE what ever 12 volt system you use you will need battery capacity to run them, any advice required pm me for phone no
cheers bob

 

[rbcoomer]

Many thanks for all the great feedback - it's all been really helpful and made me look a little further at some aspects and hopefully avoid a few mistakes too!

I'll digest a bit more over the weekend - although I'm not looking to install the heater yet, I'm installing stringers and flooring over the next few weeks and thus the ducting, vents etc need to be in place.

At the moment I think I'll go with bigger diameter ducting of 80mm as I think this will offer the best flexibility and presumably like water pipes, less resistance to airflow and minimal heat build up at the heater end? I just need to look at available space and ensure I can fit the Y pieces etc of a larger diameter!

Is there any reason I can't use this for ducting: http://www.ebay.co.uk/itm/350612513649 ? Cost is reasonable (£40 for 10M) and it will be much simpler to install as I won't need to feed insulation wrapped duct into another duct! Looking at their spec sheet it is rated between +140C and -10C and I should be able to install the buoyancy foam around it without issue. I can cut to wrap around Y joins and if needed wrap with extra aluminium foil...

Switching to 2 batteries so that's covered. With regards to water heating, I did consider that option but in all honesty I think the design/style of the boat is wrong to think about domestic water. The weight and lack of space for tank etc (even small) would be problematic and as we're not likely to overnight, the Thermos Flask will suffice! Some 21' boats are designed/geared up for a galley etc but ours isn't. It's all useful however as who knows what the next project will be...