sub 5.0m RIB - things to consider? - Page 2

BruceB · 15 May 2010, 23:23

I had a 5.3m from new for four years till I could afford to offload it. I really wouldn't recommend one if sea keeping or a good ride is a concern.
I bought another new Humber to replace it so I am not manufacturer bashing and have no axe to grind. Mine went all over the west coast to some fairly inhospitable places and rough weather but I never did rate the hull or boat.
I would recommend trying one before buying but as they say. You pays yer money and takes yer choice but an Assault would never again be one of mine.

BruceB · 16 May 2010, 12:33

See pics of transoms. Assault tubes are attached much lower on the hull than the destroyer all the way along meaning the hull is recessed in between the tubes making what is already a fairly shallow hull even shallower.
Rough chop and weather is extremely hard in an Assault on your back and legs. After a few long passages I stopped contemplating any more in anything bar a flat calm.
Also due to the design the tubes extend quite far back from the transom meaning you lose about 1ft of effective hull length and also 1ft of interior space compared to just about any RIB of similiar overall length.
The Destroyer pic shows tubes attached much higher and the difference this makes attached a reasonably deep V hull. See also the tube extensions compared to the Asault version

bosun · 16 May 2010, 13:29

Hi
Blue boat is 2010 assault 5m,yellow boat is 2001 similar,long overhang on rear sponsons gives lots of support for a heavy engine but seems to cause more cavitation especially when training new drivers (hard turns,accelerating around slaloms etc)
Would hardly call this a shallow v though?

bosun · 16 May 2010, 13:41

See what you mean about the overhang though, look at pic 2 !

BogMonster · 16 May 2010, 13:59

V-wise, it looks about the same as my Destroyer at the stern but I expect it is the low slung tubes that screw up the ride because the waves are effectively whacking into a flat surface. I don't think the bow V is as sharp as the Destroyer either.

BruceB · 16 May 2010, 14:30

I currently have a Destroyer and had an Assault. Believe me when I tell you from practical experience that the destroyer is considerably more "deep V".
The ride on the Assault is awful compared to it.
I always assumed the sponson extensions are for two reasons, to protect the outboard when on the water and backing into a garage and also to make the bow stay down, again for inexperienced cox's.
The difference in on water handling is also marked. An Assault will skip sideways flat on hard turns as not enough hull is in contact with the water. Destroyers will lean in and turn 180 degrees at 30knots within two boat lengths, or at least mine will

Other deep hulls will do this just as well or better.
The story of how I ended up buying an Assault has been recounted on here before but basically I ordered it by phone due to my location. I asked if it was the replacement model for the Attaque and when told it was I ordered it. When I turned up at the factory I was horrified to find what it actually was but by then it was too late. It was the replacement in their "model range" for the Attaque but was nothing like it in form.
Right question but not the right answer and from the day I bought it I was planning to replace it.
The Assault is really a cheap small rib for pottering around on lakes, inshore and for sailing club safety boat use where it won't be exposed to much rough weather. It is cheap, fits in a garage and it easily handled.

Downhilldai · 16 May 2010, 18:37

Deep V

BruceB · 16 May 2010, 19:47

thats not a real searider, wheres the gaffa tape ?

bosun · 16 May 2010, 19:57

When I ordered the assault they were doing a similar discount on all models,don't know if they still are though (and VAT was only 15% then)
Mind it was the depths of winter, January seems the best time to buy anything boaty ,first of all they wonder why you want it then at all ,next they offer a great price when they realise you are serious!

willk · 16 May 2010, 20:11

Quote:

Originally Posted by bosun

Mind it was the depths of winter, January seems the best time to buy anything boaty

Possibly, although I've noticed that a certain otherwise busy manufacturer seems to have a wee lull towards the Autumn (Aug/Sept). I'm guessing, but I think it's because the leisure market has their "boat for the summer" and a lot of the casual commercial guys don't want a late season completion (making their boat a year older than necessary).

9D280 · 17 May 2010, 17:31

Quote:

Originally Posted by spartacus

You're probably right on that. I'm strictly limited to 18' maximum as it will need to fit in a domestic garage, so can't even fit an A-frame, unless it's hinged so that it can fold forward.

Excatly how big is your garage? Mine (what became the Attaque before it became "Classic")fits with A- frame. Granted I asked West Mersea to supply me a shortened drawbar trailer for it, but if you have 5.7m from door to back wall, I can let you know my trailer chassis number, I'm sure if you quoted it to them they could make you another.........

Quote:

Originally Posted by spartacus

The Ocean Pro 5.0 based on the 'Attaque Classic’ has a 2.0m beam, and is rated for 90hp maximum. The weight also jumps up to 280kg. They have a picture on their website of a 5.3 Ocean Pro with a Mariner 60hp, with double jockey set-up.

Mine runs nicely with a 60, granted is only rated for same, so is a touch lighter.

spartacus · 17 May 2010, 23:16

Quote:

Originally Posted by 9D280

Exactly how big is your garage? Mine (what became the Attaque before it became "Classic") fits with A-frame. Granted I asked West Mersea to supply me a shortened drawbar trailer for it, but if you have 5.7m from door to back wall, I can let you know my trailer chassis number, I'm sure if you quoted it to them they could make you another...

18' (5.4m) length exactly. Width is standard 8' and height is 7'. I've had an Indespension Rollercoaster 1 trailer (750kg unbraked) in there and the tow hitch is hard against the wall. It has a long drawbar, and the winchpost can move forward along the length of the drawbar. It will carry boats up 4.9m in length. One thing I have to watch is - it's an 'up and over' door, so there is a possibility the engine or an A-frame could be clipped on closing. I'm not bothered about an A-frame just now, it's something I plan to add when funds allow.

Quote:

Originally Posted by 9D280

Mine runs nicely with a 60, granted is only rated for same, so is a touch lighter.

The Tohatsu 60hp (2-stroke, 3 cylinder) weighs 115kg. As far as I know it shares exactly the same block and carbs as the 70hp, There is a modification that can increase power to 70hp by adjusting the throttle stop on the second carburettor from 22mm to 14mm to get full travel. Timing is exactly the same, but with 100% throttle opening. A stainless steel propeller will also add a little more power. Factory fit is aluminium 15" pitch. Throttle operating range is 5,150 - 5,850rpm.

BruceB · 17 May 2010, 23:34

Thats fairly unusual if true, most common block outboards usually have different reeds, carbs and most especially exhausts to restrict power output.

Downhilldai · 18 May 2010, 00:24

Quote:

Originally Posted by spartacus

A stainless steel propeller will also add a little more power.

How does that work, then?

Quote:

Originally Posted by spartacus

Factory fit is aluminium 15" pitch.

What gear ratio does your Twatsoo have? Is it a 60C?

spartacus · 18 May 2010, 00:47

Quote:

Originally Posted by Downhilldai

How does that work, then?

Increased power, not as in extra horses, but more bite in the water. Increasing the pitch combined with the rigidity of a stainless-steel propeller potentially adds an extra couple knots at the business end at WOT. Propeller choice from 11" through to 21"

Quote:

Originally Posted by Downhilldai

What gear ratio does your Twatsoo have? Is it a 60C?

Model is M60 (938cc). Gear ratio is 2.3:1

spartacus · 18 May 2010, 00:52

Quote:

Originally Posted by BruceB

Thats fairly unusual if true, most common block outboards usually have different reeds, carbs and most especially exhausts to restrict power output.

I haven't tried this yet. Will only really be able to test it once it's on the boat, with the right propeller at the right operating rev range using GPS to confirm. I've read a few posts that it can be done. I looked into this with a Yamaha 40hp (model 40V) with the possibility of converting to a (50G), but it definately has bigger carburettors and a different exhaust manifold. Finding both is nigh on impossible.

Downhilldai · 18 May 2010, 01:15

Quote:

Originally Posted by spartacus

Model is M60 (938cc). Gear ratio is 2.3:1

That's the one I have - it's a very low ratio LU compared with other 60/70ish hp 2-stroke outboards. My motor was on a 'Raider' fishing boat originally - a right beamy old tub of a thing. It had a 15" pitch prop fitted, which was probably ok on the Raider, but screamed its nuts off on the SR4.7, so I fitted a 17" pitch ally prop instead, which is a lot better. I reckon 18" would be spot on for the SR4.7. A shallower hulled RIB could probably run a 19" pitch, if lightly loaded

spartacus · 18 May 2010, 12:00

Quote:

Originally Posted by Downhilldai

That's the one I have - it's a very low ratio LU compared with other 60/70ish hp 2-stroke outboards. My motor was on a 'Raider' fishing boat originally - a right beamy old tub of a thing. It had a 15" pitch prop fitted, which was probably ok on the Raider, but screamed its nuts off on the SR4.7, so I fitted a 17" pitch ally prop instead, which is a lot better. I reckon 18" would be spot on for the SR4.7. A shallower hulled RIB could probably run a 19" pitch, if lightly loaded

Interesting. If you're looking to upgrade to stainless propeller, Extreme Marine do a 18" for £200. It's shiny - get's my vote!http://cgi.ebay.co.uk/Yamaha-Tohatsu...item58837a80ce

9D280 · 18 May 2010, 12:31

Quote:

Originally Posted by BruceB

Thats fairly unusual if true, most common block outboards usually have different reeds, carbs and most especially exhausts to restrict power output.

Suz DT25 / 30 was a similar setup, although the stop was brazed to the end of the shaft so you ended up having to change the entire carb.........

[QUOTE=spartacus;353061]
18' (5.4m) length exactly. Width is standard 8' and height is 7'. I've had an Indespension Rollercoaster 1 trailer (750kg unbraked) in there and the tow hitch is hard against the wall. It has a long drawbar, and the winchpost can move forward along the length of the drawbar. It will carry boats up 4.9m in length. [QUOTE]

Remember the quoted "will carry boats up to Xm" assumes hard hulls. Your toob cones & bow overhangs will probably increase (or subtract when it comes to trailer rollers) about a metre or so. That;s why mine is a unique build - I got a braked axle on a smaller trailer. Also got 10" wheels for a bit more headroom through the door.......

I also reverse in to solve the "frame meets up & over door" problem - and have a length of old carpet underlay down the back wall to protect the engine. When the casing touches, there is a 1/2" gap between hitch & door.

Sounds like your garage is about 30Cm shorter than mine. Which frrm memory is about the difference in length between a braked & unbraked hitch. You might just get an O-pro in there!

Downhilldai · 18 May 2010, 12:40

Quote:

Originally Posted by 9D280

I also reverse in to solve the "frame meets up & over door" problem

The downside of this is having to have clear space all the way to the back wall of the garage. If you can get away with 'bow first', this allows some storage room alongside the pointy bits of the boat.

An overhead sectional garage door hardly intrudes when opening/closing, in the way up & over doors do.