CONTINUOUSWAVE

I spent a lot of time on boats as a child/teenager (35 years ago); mainly on a 27ft launch and also on smaller boats with small outboards (the latter in a river) in the UK.

We are now in Auckland, New Zealand and since 2007 have owned a 3.4m RIB with 18hp outboard. However we have used it only a little as it is too small for us (family of 5 including 2 adult children) and because it has felt too small to travel far from land in.

We'd like to explore the inner Hauraki Gulf; see:
https://www.google.co.nz/maps/place/Hauraki+Gulf/@-36.8320186,175.0033177,12z/data=!4m5!3m4!1s0x6d732874b6b9dd5f:0x2a00ef616659ae50!8m2!3d-36.4263135!4d175.1894045

There may be 5 of us on a boat, but more likely 4 with some camping gear, so we can overnight on one of the smaller islands (say launch at Beachlands on the map, and head to Motuihe or even to the far larger Waiheke).

I have always had a soft spot for Whalers; my next door neighbour had one in the '70s/'80s and always wanted to own one. However, there are very few of them here. You can get them new, but they would be out of our price range.

We have been looking to buy a 5m RIB but a 150 Sport has come up for sale. It is located a long drive away, so I have not seen it yet. However, it is one owner from new, freshwater use, stored inside and low hours (60hp 4 stroke)

Any comments on the suitability of this for us, given its size, our type of use and the distances we want to travel? We'd aim to be careful with the weather, and the inner gulf can be reasonably well sheltered.

Thanks
Richard

Compared to your RIB or the new RIB the 150 could handle your 4 adults with some gear but there won't be any room left. 5 would be too crowded for open water. Yes they are un-sinkable but your 5 meter RIB would be a better choice.
Also with 4 adults and camping gear it will take some weight shifting to get the 150 Sport up to plane and due to the Sport lay-out this wouldn't be as easily done as in a 150 Center Console.
Being that you are looking at a 8+ to 10+ km crossing in open water with a fully loaded small craft maybe capable of getting 30kmh you're looking at 30 minutes travel. With 5 persons and gear you have a hard time getting it onto plane.
Yes I would do it in my 15ft Montauk (same as the Sport except interior layout), but between the 16-1/2 feet RIB with deeper V entry and the 15 ft. Whaler I would pick the RIB.
That said the Sport would still be a great boat.

The 150 Sport is not an appropriate boat for the passenger and gear load you illustrate. It has marginal power for 4 with gear.

Taking into consideration safety factors, a 17' may be okay but a 20' or 22' Outrage would be more appropriate.

It is not the calm days you plan for but the snotty, nasty days.