Avon SR4.0 Upgrade

TimMcC · 15 February 2006, 16:35

I am thinking about upgrading from an Avon SR4.0 to a SR5.4 or something of similar length .If I put my existing outboard ( Mariner 60 Hp 2 stroke ) on the SR5.4 will it be very under powered . My uses are general cruising , no skiing or pulling toys with usually no more than 2 adults and 2 kids on board .

I have seen a few Tornado 5.4m for sale any opinions on these . Are the pcv tubes as hardwearing as the Hypalon ?.
Any opinions on the Yamaha 80hp 4 stroke verses the Yamaha 85hp 2 stroke ? . I have seen SR5.4’s with both these o/b's.

All the best

Tim

chris p · 15 February 2006, 18:55

Hi
I have a SR5.4 with yamaha f80 (4 stroke) with the hull blocked up, i fell its better than SR4. If you wont to talk wile moveing, much better fuel econimy,(30/40%better) then go for this one but it is a little too heavy on the transom, the 2 stroke is better, as fast, lighter and i would recommed it. The 60 will work on the SR5.4 but wont have the exceleration and top end you are use to.

The tornado is a good rib a little faster, a little dryer, but i stil prefer the SR5.4 better sea keeping in rough water.

kev · 15 February 2006, 20:57

I have a sr5.4 with 60 yamaha 2 stroke , it does about 32 knots which i feel is not that bad . I use it for cruising and find it a very good sea boat when using it on the west coast around sound of jura ,sound of islay.

KEV

phantom 19 · 15 February 2006, 22:33

I have had a couple of SR5.4`s, one ex forces with a 75 Hp and one with a standard tubes with a 90Hp Yamaha.
For general cruising they are good but not much cop in the rough compared to something like a humber due to being so flat, the nose tended to catch in the rough (probably why the forces ones have straps holding the tubes on the noses). The one with the 75Hp handled pretty well, the 90Hp one used to chine with the extra power when run flat out (see other post), despite being set up properly, messed around with engine heights and being trimmed (I have raced in the past). I draw the line at fitting doelfins though! It was however quick for what it was, I think I ran a LaserII on it
The tubes seemed to last very well, the standard one was a 1977 and had no leaks or patchs, although I did renew all the seam tapes and rubbing strake.

If you are set on a 5.4 then I would personally go for a Yam75/80/85/90 (basically same engine), I really like this engine, have had five or six of them in the past and no real problems, They are smoother than the hulking great Merc/Mariner 75/90. However with the Yamaha 75/90`s I found the engines would occasionally stall after being left on idle as upper casing exhaust relief would be underwater at rest due to the flooding hull sitting so low. TBH this was mainly when used for skiing waiting around for the skiier to get the mono on etc. I never blocked the hull as didnt have it for that long.

F80/100 I reckon too heavy. The transoms arent the thickest in the world, I could push against the 90 and watch the transom move so brace it with stainless angle between the stays and bolted engine through it which did the trick.

I have also had a 5.3 Humber Attaque around the same time which was very good, although tubes were knacked, I gave it away in the end and I think it was retubed. They used this hull on the oil rig support boats I think.

Rogue Wave · 15 February 2006, 23:13

[QUOTE=phantom 19] The tubes seemed to last very well, the standard one was a 1977 and had no leaks or patchs, although I did renew all the seam tapes and rubbing strake.

If you are set on a 5.4 then I would personally go for a Yam75/80/85/90 (basically same engine), I really like this engine, have had five or six of them in the past and no real problems, They are smoother than the hulking great Merc/Mariner 75/90. /QUOTE]

but if you have to the 60 will do a good enough job till you can go bigger

Searider · 16 February 2006, 09:39

Have had both 4m and 5.4m.

I would say upgrade to the 5.4m - with your 60 and see how it goes. Trading up your engine to something larger, if you feel the need, when funds allow should be simple.
As Kev has said - 32 knots is OK. I usually cruised at 22-25 ish which felt comfortable.

Regarding the transoms - they're more than up to the job of supporting a 90hp UNLESS THEY ARE DECAYED. They are plywood and water seeps down the end grain over time. Also, in their wisdom, Avon saw fit to incorporate an aluminium strip along the top of the transom secured in place with screws - a perfect way to let water in!
My 5.4m was 1978 and the transom was knackered by 2003. Still 25 years is not bad for a piece of plywood. If the one you are looking at has a bendy transom then budget for replacing it.
The two stainless steel stays should be there anyway.
Will chine walk above 35 knots.
No more likely to dig the bow in than any other RIB in my experience.

Had a 90hp Mariner on mine and it wasn't any where near as smooth as the 50hp Yamaha on my 4m

phantom 19 · 16 February 2006, 14:14

Yes I had forgotten the transoms uncapped top! Its quite a while since I had the boat but I always remember looking back on a reasonably flat day and watching the transom flexing probably three inches either way due to delamination.

I braced it between the stays with 1.5" stainless angle with plates welded on each end to sandwich inbetween the stays and the transom, then the engine bolted through the angle. I still know where this boat is if anyone wants a photo.

Compared to Humber 6.3 Ocean pro I have now the avon will nosedive and catch waves and you got completely drenched they are very flat compared to modern ribs but I used it offshore in foul conditions so for normal use they are fine I guess.

Searider · 16 February 2006, 17:10

Quote:

Originally Posted by phantom 19

Yes I had forgotten the transoms uncapped top! Its quite a while since I had the boat but I always remember looking back on a reasonably flat day and watching the transom flexing probably three inches either way due to delamination.

badbaws · 16 February 2006, 19:41

I took Rogue Waves 5.4m out 2 summers ago in a force 8.. I sat at 17knots and didn't touch the throttle, staying on the plane all the way from the 6 knot speed limit to newtown creek going wind against tide. the boat with some trim gets a good cushion of air under the bow and was a very pleasant trip.Ok so you always ship a little water.. but I have also been out on a charter in a 7.5m solent RIb with a 200hp on the back and it wouldn't even get on the plane fully trimmed down because of the nice tappered bow with no weight in it. Even moving two paying guests to the front it still just wouldn't go on the plane. I also work for the MOD and we use the 5.4m with Mariner 75hp.. they used to use 90HP but too many people were flipping them, but that said out in the middle of the atalntic doing boat transfers in large swells between ships.. how much fun do you want.. the Pacifics are too slow.. the jet versions break down too much and the seariders kick arse..Yes they chine walk at high speed, but then you learn how to drive and adapt to that.. I did my level 2 back in 1995 in an avon dive 5.6m and a searider 5.4 with a 60 yamaha on the back. with three of us it got over 30 knots and was fine to play in the needles channel in fairly ively conditions.
I have owned 2 4metre versions, have used a 4.7,and several different 5.4m. the are one of the best hulls size for size and yes they are not a dry boat... but they bring big smiles.. I used to take my 4metre out ion all weathers.. I went out in a force 7 with a Narwhal 5.5m.. he couldn't keep up.. those medium vees are.. pants!!

So yes a 60hp is fine for most uses... even ski-ing occasionaly. Don't block the holes.. keep them flooding.. and remove the outboard aluminum cap and epoxy all holes on the transom and then create your own ensuring your always silicone seal the holes to prevent water ingress.
Get a 5.4m commercial spec.. theuy last longer and when your lovely friends accidentally touch pontoons or ROCKS!!!!!!!!!!!!!!!!!!!!!!!!!!!!

then they last longer...

Alex
Ps i have seen a 5.4m with 150HP Johnson on the back about 10 years ago.. reckons he got 65knots from it.. clever or Idiot!!

badbaws · 16 February 2006, 19:45

And one final note.. a commercial spec 5.4m has far stronger tubes than a scorpion 6.5m just ask Time Teams Tony Robinson when he pranged a Scorpion down a pntoon leaving his calling card fabric destruction!!

George8910 · 16 February 2006, 20:41

I have seen a few Tornado 5.4m for sale any opinions on these . Are the pcv tubes as hardwearing as the Hypalon ?.

Has to be done really - IMHO the searider 5.4 is a most splendid way to deploy your hard earned

Have found hypalon much easier to live with than pvc in terms of repairs but also if you get a commercial or ex-mil they seem to last and last - good luck

Rogue Wave · 16 February 2006, 20:47

I don't like the PVC (unless it's on a fit woman) and i certianly don't think it weard as well. have a look at the old tornadoe's and find out I could be wrong! not about the fit woman though!

TimMcC · 20 February 2006, 10:56

Cheers guys . Thanks for all your comments .

Tim