Pendana’s Engine Room
I must confess to being a little busy on other matters at present which is taking me away from Pendana, grrrr. That being said however, Claire and I both have managed to sneak out for a day here and there while the children have been at school. Always a nice treat for the two of us being on the water without the sometimes, never ending demands from the young ones!
On the Pendana blog website there has been a new page added entitled, SURVEY/POLL. Basically this page has been added to garnish information as to the experience you all get from reading these blogs. The Survey/Poll asks for what you would like to see more of, less of and I guess not at all. It also provides a mechanism for you to offer suggestions on how I might improve pendanablog.com. The survey/poll is completely anonymous so please feel free to tell it as it is – promise you won’t hurt my feelings! I have already received some great feedback so far and look forward to providing more information on certain areas as requested.
A few of my readers have asked for more engine room photos and technical specifics so I have put together a few shots showing the main parts of the engine room and have also taken an engine room video which I have uploaded to YouTube which can be found here: http://www.youtube.com/watch?v=mzgEUQh05So&feature=youtu.be .
This video basically walks you through the engine room on Pendana pointing out the different components. Now, for those not interested in Engine Rooms – STOP reading immediately as this will be about the most boring video known to man, but for those of you who are interested then my hope is that this blog and video will give you a good feel for how things are laid out in Pendana’s engine room.
A question often asked is how do we move fuel around on Pendana between the five fuel tanks. Pendana has a day tank (used to draw fuel to engine/generators while underway), port fuel tank, starboard fuel tank, mid or centre fuel tank and a forward fuel tank. To move the fuel on Pendana we utilizing the fuel transfer manifold (Supply, Return and Transfer manifolds).
The fuel transfer system per PAE design (which I have to admit I find faultless) utilizes an Oberdorfer 013391-43-A96 positive displacement pump to move fuel from tank to tank at 3.5gpm/13.23ltrs per minute via the fuel transfer manifold. All transferred fuel is drawn from a selected tank by the dedicated transfer pick-up manifold. The fuel is then filtered and directed to the tank selected. Fuel can also just be “polished” by drawing from and returning to the same tank if required. A 60-minute transfer timer and 12-hr. polishing timer operate the fuel transfer Oberdorfer pump.
There is also a fuel boost system. This system utilizes a Walbro pulse pump to deliver a constant 5 PSI pressure to the fuel supply manifold. The boost system can be used to fill filter bowls when changing filters, bleed the engine or temporarily overcome clogged or dirty fuel filters until it is convenient to change them. This pump is operated by a toggle switch in the engine room.
Photos above and below are of the fuel transfer, supply and return manifolds, commonly called the Fuel Transfer Manifold.
Pendana has five fuel tanks, one being the day tank which is used to supply fuel to all engines while underway. The only way fuel can get into the day tank is via the transfer manifold. Well, ok that’s not quite true as we can fill directly into the day tank but this is something we never do.
To transfer fuel one would do so by selecting the tank you want to draw fuel from e.g. the port fuel tank. The fuel is then sucked out of the port tank (via a pump) and goes directly to the Gulf Stream Fuel Polisher. This ensures that the fuel is clean. Once clean the (polished) fuel is delivered to the day tank for use. Once the fuel is in the day tank and before it gets to the engine of either generator it goes via one of two racor filters as well as the engine/generator fuel filter thus ensuring total quality of fuel at all times.
When we first acquired Pendana this was without doubt the most complex of all systems, thankfully now, it makes total sense! Just a side note, all diesel engines do not burn all of the fuel supplied to them all of the time, as such, Pendana’s fuel transfer system allows for unburnt fuel to be returned to the day tank to be supplied once again and, as such, further reducing our already fantastic fuel consumption rates!
Photo above shows the twin Racor fuel filters and the Gulf Stream Fuel Polisher.
Hand drawn picture below shows the journey the fuel takes aboard Pendana.
Pendana has many types of tanks on board, these are, as follows:
Day Fuel Tank (313G/1,184Ltrs)
Port Fuel Tank (683G/2,585 Ltrs)
Starboard Fuel Tank (580G/2,195Ltrs)
Mid/Centre Fuel Tank (570G/2,157Ltrs)
Forward Fuel Tank (425G/1,608Ltrs)
Fresh Water Tank (525G/1987Ltrs)
Grey Water Tank (dishwasher/sink/shower water) (80G/302Ltrs)
Black Water Tank (heads/toilets) (140G/530Ltrs)
Water Heater Tank (hot water system) (80G/302Ltr)
New Oil Tank (50G/189Ltr)
Used Oil Tank (200G/757Ltr)
When changing oil on either of the generators or the main engine we use the Oil Transfer Manifold. The Oil Transfer Manifold (as pictured above) allows us to suck out the used oil in the engines (and send the old oil to the used oil tank). We can then simply replace the old oil with fresh oil from the new oil tank. This system is very much along the same lines as the fuel transfer system on-board Pendana. Interestingly and an advantage of the Cummins N14 is that the discharged oil from the used oil tank can actually be mixed with the fuel in any of the tanks and burned off via the Cummins NTA-14M diesel engine, so long as the concentration of used oil to fuel is kept at under 2%. I might add, we have never done this nor do I plan to as the idea of putting used oil through my Cummins main engine or either of our Onan generators is unpalatable to say the least!
Thanks to Nordhavn’s over engineering one can literally do a full oil change in a white suit and not get a mark on it!
Photo above shows the water maker we have on board Pendana. Effectively the water maker takes sea water and turns it into drinkable fresh water by a method of reverse osmosis (salt extraction). The Offshore Marine Caspian Series 1300 series water maker on Pendana is capable of making 1300 gallons/ 5,000 litres of water a day which is enough water for a family of four, for about three weeks.
In this photo above you can see our Cruisair reverse cycle air-conditioning unit with dual compressors, the Port generator (Onan 21.5kva), the N14 and air intake filter housing. Our air-conditioning unit has seven air handlers throughout Pendana allowing for individual heat/cool control at all seven stations.
The photo above shows our Duncan (get home) drive. The Duncan Drive is in a word, FANTASTIC! Basically it is hydraulically driven by either generator in the case of total main engine failure. Once the Duncan Drive is engaged it turns the shaft giving a steady 5-6kts performance allowing for one to head for home or a friendly port. Basically the Duncan Drive does away with the need for a wing engine and all the additional issues that delivers, e.g. maintenance, increased drag on hull with extra shaft etc.
This photo looks back on the engine (aft) towards the Twin Disc transmission drive (2.95/1.0 ratio). It also shows the point at which I add grease to the shafts stuffing box. Whats a stuffing box I hear you ask? Well on a boat having an inboard motor that turns a shaft attached to an external propeller, the shaft passes through what is called a stuffing box as it makes its way through the boats hull. The stuffing box basically prevents sea water from entering the boat’s hull.
In many boats, for example, the stuffing box is mounted inboard near the point the shaft exits the . The “box” is a cylindrical assembly, typically of bronze, comprising a sleeve threaded on one end to accept adjusting and locking nuts. A sound stuffing box installation is critical to safety because failure of this often misunderstood and unloved piece of kit can allow a catastrophic volume of water to enter the boat very quickly!
In a common type of stuffing box, rings of braided fibre, known as shaft packing or gland packing, form a seal between the shaft and the stuffing box. A traditional variety of shaft packing comprises a square cross-section rope made of flax impregnated with wax and lubricants. A turn of the adjusting nut allows for easy compression of the shaft packing. Ideally, the compression is just enough to make the seal both watertight when the shaft is stationary and drip slightly when the shaft is turning. The drip rate must be sufficient to lubricate and cool the shaft and packing, but not so much as could sink an unattended boat. Thankfully Pendana had her box, re-stuffed a few months ago!
Maybe the photo below will help explain a little better.
Photo above is self explanatory other than to note the N14 is fitted with two alternators a 24volt and 12 volt. In the bottom right side you can just see the 24volt alternator in red.
The two photos below show both the 24v and 12v alternators running from the main engine which are used to provide an abundance of power to Pendana while underway.
Above, 24v alternator.
Above, 12v alternator.
Pendana, unlike many Nordhavns is fitted with a Cummins N14 main engine while most Nordhavns run John Deere or Lugger engines. Back when Pendana was built (and I even think to this day) the Cummins is the choice deisel engine for the US Military after the US Government trialed all diesel engines on a continuous run basis for twleve months. The Cummins N14 was the hands down winner!
There are certain advantages to the Cummins in my view, least of all is its lower fuel consumption rates. Typically Pendana runs on average at around 9kts and at 9kts Pendana consumes approx 5.5G/20.8Lts of fuel per hour making her incredibly economical to run. She also achieves this speed with its main engines rpm at a very low1250rpm making this engine not only incredibly quiet but also very cheap to run.
From dicussions with other Nordhavn 62 owners their Lugger/John Deere equivilents consumer approx 3G/11.34Ltrs per hour more fuel to achieve the same speed. Why is this important, well on the recent Whitsundays trip north we travelled around 2,500nms meaning that we burnt 1,527G/5,772Ltrs of fuel. When we compare this with the average non Cummins engine on a similar trip they would have consumed 2,361G/8,924Ltrs of fuel. This equates to a staggering 834G/3,152Ltrs more fuel consumed for the same trip with non Cummins engine. At around A$1.60 per litre this is a saving of around A$5,000 dollars on this one trip alone! Please note that I am not trying to compare current day John Deere/Lugger engines with Cummins, simply stating an observation of what Pendana and other similar year model Nordhavns have and their fuel consumption differences.
Photo above shows one of two 21.5Kva generators which, in this photo is the port generator. I have taken off both generator housings as while they are great for a little nose reduction it makes it impossible to see if there are any issues with the engine/s while underway. I am not sure how one spots an oil leak with the housing intact! Both of our Onan generators have around 4,800 hours on them and sound as good as the day they were installed (almost)! Cummins / Onan actually told me at the engine hours we have on them that they were just getting run in!
Photo below of Pendana’s sea chest.
The Sea Chest on Pendana consists of two (2) 2 inch strainers which bring raw water in from two (2) separate through hull fittings which supply the sea chest with raw water (salt water/sea water). The sea chest in turn supplies, via bronze body valves, the following equipment: both starboard and port generator and the water maker. The chilled water air conditioner is supplied direct through its own strainer/thru hull as is the main engine.
Photo below of the two Groco sea strainers on Pendana’s main engine.
The main engine is kept cool by the use of a Walter Keel Cooler and is what is referred to as a closed system. Basically, fresh water cooling systems, also known as closed cooling systems, come in several varieties. The most common type (not used on Pendana) utilises a Heat Exchanger which functions similarly to the radiator in your car. Coolant (antifreeze) is circulated through one side of the heat exchanger where it is cooled by raw water that passes through the other side of the heat exchanger. The engine coolant is then circulated back into the engine. The raw water is then expelled out of the boat through the exhaust. Another common type of closed cooling systems is known as a Keel Cooler (used in Pendana). This is done by eliminating the use of a heat exchanger. Instead of pumping raw water into the vessel’s heat exchanger where it cools the coolant, the coolant is pumped through pipes or aluminium extrusions on the outside of the hull where the surrounding water (lake, river or sea water) cools the coolant before it is pumped back into the engine (cool). The use of keel coolers removes the need for a heat exchanger, raw water pump and the other components necessary for pumping raw water into the heat exchanger.
Below diagram shows roughly Pendana’s cooling system.
Below is a photo of Pendana’s coolant thru hull, this is where the hot coolant leaves the engine, exits the boat and where it returns as cool, coolant.
Below photo is of Pendana’s keel cooler which is recessed into the starboard underside of hull.
So for those of you interested in all things ‘engines’ which I can tell you I am not, I do hope that this has given a pretty good idea of how Pendana’s engine room is set up together with its key systems.
Now for something completely different! For those of you out there interested in writing a guest piece for Pendanablog I would be more than happy to include it in the next post. Please feel free to send it to via email to me with a few quality photos. The guest blog could be of your own boat telling us all why you love it so much. It could be of a recent trip you did or it could be something completely different. It’s up to you, so if you are interested in sharing and feel the urge to write then please send me what you have for inclusion. Needless to say, would like to keep it on point, i.e. boating topics in general!
And in closing….