Southstar 37

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Southstar 37

Author : Barry Thompson


Southstar is the fourth Southstar 37 to be launched but the first with outboard power. The three preceding all had Yanmar 450hp diesel engines through conventional shaft drives. So why the change?


According to builder and boat owner Greg Salthouse the decision to go outboard came after doing a lot of research into both options and in the end the outboard choice seemed to be the right way to go. “I knew what the diesel powered Southstar 37 would do as we already had three on the water and I also wanted something different”.

There are a number of obvious advantages going the outboard way both in extra available space in the boat and the initial build price. Both factors that Greg saw as very positive reasons to go outboard.

“We were able to fit an extra queen double in the guest cabin, plus gain extra storage space, albeit for a small sacrifice of space in the aft centre of the cockpit”, says Greg.

He adds that the fact he saved around $NZ150,000 in the price of the whole boat/engine package and as a builder also around 550 hours in build time were more reasons why the outboard option looked good. The outboard arrived at Salthouse Boatbuilders Greenhithe yard only two days prior to Southstar being launched and was fitted in a morning.

“The fact that we can tilt the motor completely out of the water when at rest means we have no running gear sitting underwater when at rest and any maintenance or service is that much easier and quicker than an inboard diesel”, says Greg.

But what about fuel costs? While not such an issue in Australia where petrol and diesel are similar in price, it’s a different story in New Zealand where diesel is generally around $0.65 to $0.70 per litre cheaper at the marina pumps than premium grade 95 octane petrol.

Petrol vs Diesel

To find out just what the costs are we took the fuel and performance figures of a Southstar 37 powered by a Yanmar 6LYP @ 450hp through a conventional shaft drive and the new Yamaha V8 outboard powered Southstar and compared them.

The inboard Southstar 37 has a displacement around 7000kg, whereas the outboard powered Southstar is closer to 6000kg. However, while the composite GRP hulls and superstructures are identical, due to the different weight transfer (mid engine inboard @ 515kg to stern mounted outboard @ 373kg), tankage and some standing equipment were repositioned to rebalance the boat.

To put 1000 litres of petrol in Southstar is around $NZ670 more expensive than 1000 litres of diesel. That in itself would put most people off. However, when you compare the running and capital costs of each boat you can quickly see that in reality, for typical pleasure use, the Yamaha V8 350hp outboard is actually reasonably economical to run, despite burning more than twice the dollar cost of fuel than the diesel, per nautical mile.

On the shakedown cruise over Xmas, Greg said that Southstar used 850 litres for 50 hours of running, which was an average of 17.0L/h. “Most of our cruise passages were around 3800-4000 rpm, which gave us around 18 knots, although a lot of the time we were under 10 knots when we were gunkholing in the Bay of Islands and Great Barrier”.

If you are still not an outboard convert then not only is the Southstar 37 available with a shaft drive inboard, either direct or with a V-drive, it can also be reconfigured with twin or single sterndrives and also pod drives.

Slippery When Wet

The Southstar 37 is an easy boat to push and as the performance figures show can get up and go when required. The big 5.3 litre V8 Yamaha 350 has the torque throughout the range to give this 11m cruiser the agility of a 6m runabout. The Southstar 37 outboard is really a fun boat to drive.

Since launching Greg has fitted a Permatrim, which he says, in tight cornering has eliminated any prop ventilation and improved the low speed tracking , although at the expense of a little less top end speed. Southstar planes as low as 9 knots.

Underway the only really noticeable difference in the handling of the outboard powered Southstar 37 is that it is much more nimble at very low speeds with more control. At high speeds both versions handle very much the same, albeit the outboard is certainly more responsive.

“Before we went ahead with the outboard project we sent all the necessary data about the boat to Yamaha and they came back with speed calculations of around 26-27 knots, so they weren’t far wrong”, said Greg.

When first launched with a 16 ¼” diameter x 20” pitch prop Southstar got close to 30 knots in light ship mode, but was a little sluggish down low. For the review Southstar was running a 17″ Yamaha propeller, but this is to be changed to a smaller 15″, and Greg feels confident that this will get back one or two knots without sacrificing the low-end performance too much.

Four-stroke outboards are reknowed for their quietness and the big Yamaha V8 is no exception. Our decibel meter indicated a very quiet 71dBA @ 2000 rpm and 78dBA @ 2500 rpm at the helm. At 18 knots or 4000 rpm this increased to a very acceptable 86dBA and that’s with the rear doors and windows removed.

If you feel you’de be just as happy with a top speed in the low 20 knot region then a single 250hp – 300hp outboard would easily do the job and there is also the option of a pair of 150hp -175hp, as there’s plenty of available space to fit them.

Construction is conventional GRP, with the running surface traditional monohedron with constant deadrise over the aft planing sections, with a variable deadrise forward, rising to a fairly sharp entry bow. Deadrise at the transom is 13 degrees.

Basic and Functional

Southstar is not a complicated boat, but then it was never intended to be. It is simple and clever without all the push button mod cons, well designed and a functional boat that ticks all the boxes in the comfort, layout and finishing areas.

Southstar is quite devoid of options and while you can certainly have just about anything you want aboard, Southstar has purposely been kept basic in many respects. For example, the rear saloon doors are removeable panels which stow in the cockpit, as are the rear bulkhead perspex windows which have their own dedicated storage place inside. You can have folding bifold doors and a hopper or retractable window if you desire – it’s your choice.

While the layout of the interior has been much the same for all three previous boats you have the ability to customise it. Southstar differs from the others due to the extra space available from the previous engine area and this really shows in the accommodation plan. With the diesel inboard option you have a double berth forward and two singles to starboard, whereas with the outboard package you can fit two doubles plus the two singles in the two-cabin layout. If you opt for a couple of diesel sterndrives, pods or even a V-drive single diesel as your choice of power then this same layout would also be possible.

In Southstar the head/shower area has been swapped over to the starboard side and the second cabin is to port. This not only retains the two single upper and lower berths but has an athwartships double as well.

For’ard is the master cabin with a central island berth with storage in side shelves, under the berth and side lockers. The ceiling is all tongue and groove painted timber which is run throughout the boat.

The en-suite, shared by the two cabins, has a composite vanity surface with raised bowl, a large shower unit and is finished off with a teak and holly sole.

The saloon is surrounded by high profile side windows and with the raised port side settee you get great all round visibility – great for sitting and watching what your neighbours in the bay are doing. Plenty of Hella LED flush mounted overhead lights keep the area well lit. The table also drops down to convert the area into an extra double berth.

The galley takes up most of the starboard side of the saloon and has an almost full-length composite bench top with the usual storage lockers and drawers beneath, plus an Isotherm fridge/freezer unit, two-burner gas powered stove and space for an underbench oven.

The forward steering station has also been kept as simple as possible, with minimal instrumentation, switches and a single Garmin GPSMap 5008 display. Greg points out that like the rest of the boat, this area is totally custom built to suit whatever a client wants. When Southstar was launched it didn’t even have a helm seat, but this was due to be fitted “sometime soon” says Greg. This will be a cantilvered double helm seat that sits over the end of the galley vanity and drops down out of sight when not required.

Easy Living

When you step into the cockpit it’s hard to miss the large central engine box which covers the Yamaha V8 outboard. In the diesel version the whole transom folds down to make the boarding platform, but obviously that’s not possible with the outboard. The plus side is the engine box doubles as a great benchtop when fishing, or as a table when eating outdoors.

There’s access either side to the boarding platform which still runs right across the transom. The cockpit sole is all teak and ample use has been made of storage areas underneath. For overhead protection Greg uses a couple of removeable poles from each corner of the transom and a soft removeable cover which he says worked great over summer.

The appeal for a boat like this is certainly broad and it has definitely attracted the attention of yachtsmen who are looking to move into the more sedate boating lifestyle that a boat like the Southstar can offer.

It seems that the strongest enquiry level for the Southstar 37 is from Australia. “We have one in Spain, one in Australia and now two in New Zealand so we are well spread with the few we have built already”, says Greg.

The outboard option has certainly broadened the appeal of the Southstar to a much wider market.


  • Boat Design Name: Southstar 37
  • Boat Name:  Southstar
  • Year Launched: 2011
  • Designer: Nick Peal
  • Interior Designer:   Greg Salthouse
  • Builder: Salthouse Boatbuilders Ltd
  • LOA:   11.15m
  • Beam: 3.91m
  • Draft: 600mm (Engine down)
  • Displacement: 6000kg
  • Max Speed:  24.5 knots
  • Cruise Speed: 18 knots
  • Construction: Epoxy composite
  • Fuel Cap: 1200 litres
  • Water Cap:   600 litres
  • Engine Make: Yamaha V8 @ 350hp
  • Drive Train:  Outboard
  • Price As Tested: NZ$580000

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