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POD Drives - Something cool in boating

Riviera 51Ok, it's important to give you a little bit of background on me. First of all, I love big boats and I cannot lie. That's all the background you really need.

I've had a number of boats, which is why I no longer buy a copy of Trade-A-Boat Magazine because each time I do I buy a boat. I've seen the light and stopped buying copies of this quality, but ultimately, expensive publication.

Now, for many years there have been few propulsion choices available to boaters and the size of your vessel dictated whether or not you had Outboards, Stern Drive, or even Shaft drive. The boats I like are the bigger ones with luxury accommodations which I can take advantage of whilst my wife throws up and continues fishing. Yes, you read it right, my wife loves fishing more than I do and will do it all day every day if you let her. She gets seasick but that doesn't stop her, she just throws a bit of extra burley over the back and continues to fish until we run out of food & fresh water.

Generally speaking larger boats, 30 footers upwards, are Shaft Drives. There's no question that bigger boats not only cost loads of money they also cost and absolute fortune to run, with added expenses such as mooring, Anti-Fouling, and generally more maintenance. All these things add up to bucket loads of cash and anything you can do too reduce those costs is going to be looked at seriously by potential buyers.

Fuel usage on larger boats is measured in Litres Per Hour and you can expect to use lots of it motoring around looking for the perfect fishing spot or somewhere to spend the night. Because fuel usage is the largest outlay along the way we'll often do just about anything to reduce it. That's where POD technology comes in. What an ingenious drive system, one that gives you better control as well as better performance and economy. That has to be a good thing.

Traditional Shaft Drives are old technology

In traditional Shaft Drives engines are mounted further forward than Outboards or Stern Drives with a long Shaft coming through the bottom of the boat (at an angle) with a propeller jammed on the end. Steering is accomplished with the use of Rudders which sit in, and direct, the water flow.

A configuration like this creates balance because engines are heavy and mounting them roughly in the middle of the vessel spreads the load. On the other hand, there are drawbacks, the most obvious being the direction of propulsion. The angle at which shafts exit the boat is never perpendicular to the base of the hull which means some thrust is wasted because it's trying to push the boat up into the air rather than forward. It's simple geometry my dear Watson.

One of the other disadvantages is that having engines mounted amidships requires space, space that could be better used for other things such as the mounting of a decent Beer Fridge or Tennis Court, Swimming Pool, or in my case, more accommodation space.

PODS

POD Drives are more efficient for a raft of reasons but require more maintenance than other forms of propulsion. PODS are similar too "Legs" on a Stern Drive except they come right through the bottom of the hull. They're directional and therefore you don't need Rudders, because they can be Manoeuvred up, down, and side to side. POD Drives, in the case of ZEUS, can negate the necessity for Trim Tabs as well but more importantly the direction of thrust is straight out the back where it should be. Which means you are being moved forward rather than upward.

An interesting difference between POD and Shaft is that Shaft Drives tend to push you along whereas a POD can be forward facing which pulls you along.

There are some very interesting benefits to using POD over Shaft, the most important being the increase in efficiency which in turn reduces fuel costs. A gain of between 15 and 30% can be equated to a substantial financial benefit long term. PODS can also give you greater control & manoeuvrability which is very important when trying too get yourself into a tight parking space with a good cross wind.

A disadvantage is that boats need to be specifically designed to use PODS because the weight of engines is moved right up to the back of the boat and the Centre of Gravity moves aft. You cannot simply pull out traditional Shaft Drives and plonk-in a couple of PODs because the movement of the CG will adversely affect hull performance. This adds a cost to boat builders whom need to rethink the mathematics of boat design, geometry and various other balance issues.

ZEUS vs. IPS

ZEUS is the Mercruiser offering whereas IPS comes from our friends at Volvo. There are subtle differences, for example the ZEUS offers GPS Station-Keeping as standard. At the end of the day your choice will come down too your own particular likes and dislikes, some prefer Mercruiser over Volvo. It's a bit like supporting a football team, you faithfully support one or the other regardless of how well they perform and how many matches they win.

Maintenance

PODS cost more to maintain because they're more complicated with more moving parts than traditional Shaft Drives, but the performance increase and fuel efficiency outweigh the additional costs. Not to mention the space that becomes available.

The nature of boats which are permanently in the water is that you must maintain them to prevent them falling apart right before your eyes. Salt water is very unforgiving and will destroy your pride & joy without giving you a second thought. Anodes or sacrificial metal will ease the devastation caused by electrolysis, regular Shaft, Leg, Prop maintenance, Anti-fouling, and so much more. All these things add to the cost of owning a boat with a bit of size. Let's face it, putting a 50 or 60 footer on a trailer too take it home isn't really an option. There is a very good reason people often refer to a boat as "A hole in the water you throw money into".

Riviera Australia use PODS

Riviera are Australia's largest exporter of Luxury boats and are synonymous with quality, space, and use of the latest technologies which sets them apart from the competition. PODs form part of their impressive lineup which tells me there's something in the hype we're all hearing.

I've concluded that Riviera have been sneakily using "Time Lord Technology" which means their boats are bigger on the inside than they are on the outside. If you don't believe me, get on board and take a look for yourself.

I've recently been interested in purchasing the 63 Enclosed Fly Bridge but they're not available with PODS whereas the 53 Enclosed Fly Bridge is (IPS), and the difference in space and living accommodations is astounding. By removing the Shaft Drive Riviera have been able to include a Full Beam Stateroom featuring a king sized bed, sitting room, and private bathroom. All made possible by the inclusion on PODS. How much more convincing do you need?

Riviera plan to release their new 50 footer at the Sydney Boat Show in August 2013 and the overall styling and available space is incredible. The new 50 Enclosed Fly Bridge comes with ZUES and offers incredible performance & outstanding fuel efficiency consuming just 180 Litres per hour at a comfortable 22.5 knots.

Fuel Savings

The additional efficiency has the potential to save about $120 per hour in running costs, assuming Diesel costs about $1.60 a litre at the pump and your boat consumes around 260 Litres an hour. If you do 10 hours per month then you're saving about $14,400 per year. That's an awful lot of beer! Surely savings like that outweigh the additional maintenance costs.

Conclusion

If you're into bigger quality boats then take a good look at vessels that offer POD as an option. I think you'll be surprised at the long term benefits. This is not a paid advertisement for Riviera by the way, in fact they have no idea I've even written this article. In fact, I wrote to them and asked permission to use one of their photographs but they didn't both too even get back to me.

That's all folks, you're dismissed - for now!

Published 29 July 2013

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