AB RIB/ outboard combo help

[CLC3]

You can't go wrong with an AB. Let me also advocate for a similar combination that's worked very well for me: an Achilles 335AX with a Tohatsu 20HP (manual start; electric start is available).

The RIB is 11', has an aluminum hull and a double floor and a large locker - big enough to hold the fuel tank (fuel line runs astern under the floor). It's wide and stable. With an SE Sport 200 hydrofoil, the Achilles planes at 1/3 throttle with just me (225) and with 4 full-size adults gets on plan with full throttle and then maintains plane when backed off. The Tohatsu, like most current fuel injection 4-stroke engines, is an absolute miser on fuel.


- Chip

[Nibiruwayne]

Originally Posted by kwf05001

Currently trying to commit to a new RIB/outboard.
We currently have a 2008 Avon 280 RIB and 2012 Merc 4-stroke 9.9. By spec the combined weight is 224lbs.


We want an electric start for my wife's elbows, ability to plane with 4 or 5 adults, max length 10'6". I'd prefer a yamaha, but in a 20hp the tohatsu is 26lbs lighter (and of course cheaper). With the 25hp the yamaha's weight makes it no contest.



Our top contenders are:
1. AB 10 VL with Yamaha 25

combined weight=255lbs, more hp, slightly cheaper, fiberglass hull, no bow locker, boat backordered until May or June, engine in stock now

2. AB 10 AL with Tohatsu 20

combined weight=232, 5hp less, $660 more, 23 lbs lighter, Aluminum hull with bow locker, boat and engine in stock now



Thanks,
Kevin

Kevin- I had an 10.5 ARB rib, glass, bow locker, 25 Hp Yamaha. Lots of speed with 5 adults. Now I’d go with the aluminum hull and a 20 Hp would be plenty for me.
Can you buy the Yamaha and the aluminum hull..

[SV Delia]

I have a 10.5 Ab and I had to get more engine because the v hull design didn't get on plane with my Yamaha 9.9 four stroke with 2 big boys aboard. I upgraded to a 15 hp but even that isn't enough for 4 or 5. The hull design makes for a dryer ride but does require more push.

[NewOrca]

We have exactly rig #2, selected expressly for the low weight and great performance. There is no problem to plane with 4 adults. This is very stable and dry dinghy for its size. Love the false floor, battery and fuel tank in bow with cord and hose beneath the floor. Great choice. Whole rig is under 250 lbs with fuel. But we would probably put the outboard on the rail if we go offshore...and maybe the dinghy on the foredeck, too. But for coastal cruising the whole rig is happy in the davits.

[TabbyCat]

Originally Posted by kwf05001

Currently trying to commit to a new RIB/outboard.
We currently have a 2008 Avon 280 RIB and 2012 Merc 4-stroke 9.9. By spec the combined weight is 224lbs.


We want an electric start for my wife's elbows, ability to plane with 4 or 5 adults, max length 10'6". I'd prefer a yamaha, but in a 20hp the tohatsu is 26lbs lighter (and of course cheaper). With the 25hp the yamaha's weight makes it no contest.



Our top contenders are:
1. AB 10 VL with Yamaha 25

combined weight=255lbs, more hp, slightly cheaper, fiberglass hull, no bow locker, boat backordered until May or June, engine in stock now

2. AB 10 AL with Tohatsu 20

combined weight=232, 5hp less, $660 more, 23 lbs lighter, Aluminum hull with bow locker, boat and engine in stock now



Thanks,
Kevin

Kevin,
Get a lightweight dinghy, (we have a 3.5M OC tender which is 12' long), then the 9.9 Mercury will drive the boat at 24 knots with 5 people onboard. Or two people with lots of dive gear. Or lots of provisioning! Not only is OC tender lighter than a deflatable, there is no drag of the tubes in the water which has a significant effect on planing - it just gets us an goes.

[Adelie]

Look here:

https://www.cruisersforum.com/forums...ml#post3516272

[Cheechako]

That's a lot of HP for a 10 ft boat. My 10 ft AB RIB with 15HP Yam would plane (barely) with 4 small adults. But the RIB was a heavy double floor. I think 135#. It was squirrely with one or two people though.

[FlyingScot]

Originally Posted by TabbyCat

Kevin,
Get a lightweight dinghy, (we have a 3.5M OC tender which is 12' long), then the 9.9 Mercury will drive the boat at 24 knots with 5 people onboard. Or two people with lots of dive gear. Or lots of provisioning! Not only is OC tender lighter than a deflatable, there is no drag of the tubes in the water which has a significant effect on planing - it just gets us an goes.

Can you post a video of this? I'm not saying it's impossible, just shocked that the hard dinghy can propel 5 people 24kts on 10hp.

During covid times, we raced our friends OC 350 vs our AL9.5. We had our Enduro 15 hp 2 stroke vs. their yamaha 4 stroke 15 hp. Both had roughly the same weight (2 adults). Starting from a dead stop we easily jumped into a big lead with our 2 stroke. We top out around 21kts. They maybe were going 22kts slowing catching us over about a mile.

[Mark424]

Not to go too far off topic, but since the topic of AB vs Highfield came up, curious in anyone has weighed either one. On the spec sheet the Highfield is quite a bit lighter. Curious if this is marketing spin or they actually did find a way to take more weight out.

[malbert73]

I have a Highfield CL290 with 15hp Tohatsu EFI 4 stroke. Great setup. Can plane with 3 adults and our 2 kids. I pull kids on tube or wakeboard also.
Comments that may help OP
1. Bow locker and flat second floor is so much better, having chartered for a week with a UL type AL dinghy with tough to stand on V floor and always wet feet. I’d strongly consider that
2. I think many outboards are pitched too coarsely for what we do. I don’t need/want 20+ knot top end, I want more low end power to get on a plane. So I bought a 1 inch finer prop from defender this off-season to get up easier when loaded (as my 10 and 12 year olds keep growing). New prop is 9 inch pitch, old one was 10. So what if top speed is 18 instead of 20?

[paradox]

I am trying to keep weight to a minimum. I have a Highfield 2.9. looking to purchase a 4 stroke outboard. do you think I can get on plane with either a 5hp or 8 hp engine?

[malbert73]

Originally Posted by paradox

I am trying to keep weight to a minimum. I have a Highfield 2.9. looking to purchase a 4 stroke outboard. do you think I can get on plane with either a 5hp or 8 hp engine?

If you’re not heavy, and alone, possibly with an 8, almost certainly not with a 5 if it’s a rib

[kwf05001]

Thanks for all the responses everyone!!! At first there seemed to be a leaning towards more horsepower, but now the majority seem to say the benefits of the AL hull are worth giving up 5hp and that 20hp is adequate.

I'm still on the fence. I think I've considered all my options and just need to decide on what factors are most important.

I'll let everyone know what we decide and how it works out. Thanks again.

[CAELESTIS]

Originally Posted by kwf05001

Thanks for all the responses everyone!!! At first there seemed to be a leaning towards more horsepower, but now the majority seem to say the benefits of the AL hull are worth giving up 5hp and that 20hp is adequate.

I'm still on the fence. I think I've considered all my options and just need to decide on what factors are most important.

I'll let everyone know what we decide and how it works out. Thanks again.

Why not get the lighter dinghy with the bigger motor? You can always throttle down.

I am about to put a Yamaha 25 2 stroke on my 11ft Highfield. I went through your same process—15hp would not plane the four of us.

[SirChaunchy]

Originally Posted by kwf05001

Currently trying to commit to a new RIB/outboard.
We currently have a 2008 Avon 280 RIB and 2012 Merc 4-stroke 9.9. By spec the combined weight is 224lbs.


We want an electric start for my wife's elbows, ability to plane with 4 or 5 adults, max length 10'6". I'd prefer a yamaha, but in a 20hp the tohatsu is 26lbs lighter (and of course cheaper). With the 25hp the yamaha's weight makes it no contest.



Our top contenders are:
1. AB 10 VL with Yamaha 25

combined weight=255lbs, more hp, slightly cheaper, fiberglass hull, no bow locker, boat backordered until May or June, engine in stock now

2. AB 10 AL with Tohatsu 20

combined weight=232, 5hp less, $660 more, 23 lbs lighter, Aluminum hull with bow locker, boat and engine in stock now



Thanks,
Kevin

Kevin, I have the AB 10 with the aluminum hull and I've had my Suzuki 20 hp fuel injected motor for about 10 years. It still starts every time on the first pull and I believe it has an electric starter option as well. It only weighs about 99 pounds and runs almost forever on a small tank of gas. I like the aluminum better than fiberglass because I'm an explorer out at the local islands off the coast of California and many of the beaches are rocky so the aluminum takes a beating better than the fiberglass.