3.9m vs 4.2m boat to buy

[pezza]

Hi everyone. I need some help. I am currently a 3.9m sib owner with a 20 hp and looking to upgrade to a rib. I am lucky enough to store my boat in Christchurch near a slipway and currently wheel it directly into the water by hand. My budget is around £8,000 and I had my heart set on a 4.2 m aluminium rib to keep the weight low for easy retrieval etc. I have found several boats between 4-5k ( bare boat no console trailer etc ) but the problem lies with the engines. Availability is the 1st problem and then the jump in price is extortionate. A 25hp outboard is roughly 3.5k but a 30hp is 5.5k.
I have seen a 3.9m rib ( 1k cheaper to purchase ) with a deadrise of 20 degrees which looks the same as it's 4.2 bigger brother with a weight of 60kg ( 55kg less than it's bigger brother ) and can take a 25hp. I am looking to put a dual jockey console in the boat also.
Is the extra 30 centimetres worth the extra £5,000 investment, 90kg weight increase and increased fuel costs? I am very interested to hear your thoughts especially on the difference in riding it in the chop.

I know having a much bigger rib brings with it way more benefits such as storage space, ride comfort etc but generally I will be using this rib by myself or with 1 other adult and want to keep the mooring costs down ( £ per metre ) and the usability up by being able to easily launch it by myself near the water. Having cheaper fuel costs is also a plus. One last thing buying a second hand boat package with an old engine is not an option for me. My father scarred me for life by constantly braking down on the water when I was a small child so that is not happening

All the best

Pezza

[rik_elliott]

I would ask what your motivation for the upgrade is. What does the sib not do that you feel you need? From what you have said you want (easy launching, decent engine etc) it sounds like you already have a good rig. I would hate for you to spend lots of cash on what might be only a small improvement in sea handling.

A rib with a flatter hull just won't be that much better in the rough than a good sib.... it will likely take a bit more of a beating but it will slap hard in chop and make you not want to go out!

As an alternative option - if your sib has an aluminium floor had you considered putting a jockey console on it and adding remotes to your engine? Add a trailer and it will feel like a different beast and be a lot cheaper than replacing everything. I put cross bar steering on my honwave 3.8 air deck and it made it feel like a far better boat.

If you really need a good sea boat of 4m size i would be looking at a searider and putting a new engine on it - mine went fine with 30hp with one or two aboard.

[rik_elliott]

Here is my honwave with steering rig for reference

[chipko]

Whilst it is very true ‘length matters’ in terms of sea keeping, the difference between a 3.9 or 4.2 version of the same boat will be a marginal gain only. My only query would be with such a large weight difference between the two are they actually based on the same hull?

[pezza]

Many thanks for your quick responses. Unfortunately my sib is an air floor with no aluminium on it but it is just too slow in the chop. I have to take it slow due to the slamming of it. I am definitely after a deeb v hull rib of 20 degrees deadrise or higher. I am looking at the 3d tender xpro. I am trying to paste in the specs of each model
XPRO 420 XPRO 415 XPRO 390
Overall length (cm) 420 415 390
Overall beam (cm) 187 187 186
Inside length (cm) 293 289 272
Inside beam (cm) 89 89 86
Bow locker width (cm) 67 67 67
Stern height (cm) 103 103 103
Bow height (cm) 67 63 58
Total weight* (Kg) 128 89 69
Max load (Kg) 900 860 700
Aluminium Thickness (mm) 4 / 5 2,5 / 3 2,5 / 3
Tube (cm) 50 50 45
Shaft Long Long Long
Max. power 60 25 25
Front locker Standard Standard Standard

It's quite a big jump in weight. From the pictures I have seen the hull looks almost identical between the 390 and 420 and the dealer has also said he can't noticeably see any difference. I know the xpro 420 has done a channel crossing so I am hoping the deep v should be a big difference to my current slamming sib. But is the 4.20 worth the cost over the 3.90.....

[The Gurnard]

Originally Posted by pezza

But is the 4.20 worth the cost over the 3.90.....

The answer is in the specs you posted pezza .. Aluminium Thickness (mm) 4 / 5 2,5 / 3 2,5 / 3

I presume it means ... The 420 boat size .. is 4mm / 5mm thick Aluminium (4mm thick hull skin ?)

The other two boat sizes are 2.5mm / 3mm thick Aluminium (2.5mm thick hull skin ?)

Ask the dealer again to confirm the difference as he should know

Which explains the price difference ..the weigh and power rating difference.

For info only .. I have a 420 Quicksilver Alu Hull boat and before it ... I has a Quicksilver 420HD wooden floor SIB.

The Quicksilver Alu Hull is not a deep V like the XPRO but I can keep up my speed a lot longer in chop with the Alu Hull boat that I could in the SIB.. so I’m sure you will def notice a difference too...regardless of which model you decide is best for you.

[chipko]

Quick scan of the 3D Tender website confirms comparing ‘apples to oranges’
The 420 quoted weights will be the Xpro Defender whilst the 390 is a different model Ultimate Lightweight rib, hence the significant weight difference with thicker hull, more beam, bigger tubes, long shaft motor and significantly higher power rating, etc. etc.
Only fair to compare 390/420 Ultimate lightweight ribs but the website specs also throw up some inconsistencies….both same weight at 69kg? and max 25hp but 420 longer, wider, long shaft versus short shaft bigger tubes, same motor rating!!
All seems a bit of a minefield to offer any informed advice to be honest.
As an aside we now run a tiny 3.4 Ocean Runner rib with 20hp on tiller. It’s faster than a previous T38 with same motor, but a harsh ride in chop. More fun, more responsive and suits our needs, but in reality we could push on faster in the T38 with more comfort in typical UK chop

[Locozodiac]

Go for the Rib size that will handle your existing size motor that's been powering your Sib lately. It's a night day difference boating with same size Sib/Rib running similar motor. If a Sib is badly inflated will achieve a much comfy softer water ride than same Sib well inflated to their max working pressure factory stated...

Happy Boating

[1Speed]

I have an X-Pro 4.2 defender with a Mercury 40. I have owned her for about 4 years and she has not let me down in any way. She will cruise at 20-22 mph and flat out about 26 mph. She is easy to launch and handle and great fun single handed or with the family.
I keep her in Southampton, as you are close by if you want to see her in action let me know and ill take you out in Southampton water and you can form your own opinions.

[pezza]

Hi guys many thanks for your replies. Sorry I have been quiet this week. It's probably due to shock of the MRs allowing me to buy a bigger boat. I have managed to pick up a 2nd hand highfield club 460 with a honda 40 on it. I am still in shock. I haven't managed to take her out properly yet but will let you guys know how I get on. If any of you guys are ever near Bournemouth please let me know and we can head out on the boats. Awesome vids by the way "The Gurnard". I am super jealous of your Scottish play grounds.