Smallest realistic Size of engine for sr5.4

[benjytaylor]

Any ideas what is the smallest 4s for my sr5.4 I can get away with.
Do any of you use 50/60 4s and if so how do you get on
The hull is going to remain uncapped.
Does anyone know of a decent lump for sale??

[Starovich]

Have used 40hp 2stokes on 5.4's take a while to drain the hull, but then ok once on the plane.

[chris.moody]

I occasionally use a SR 5.4 with a Honda 50 4 stroke, WOT 1 person, flat water, engine trimmed, 25 litres of fuel, 2 anchors. 26 kts, but it does take a while to empty the flooding hull with that amount of HP.

[chris.moody]

The one I use is a club safety boat and for that purpose it is ideal with a 50. I also use a tornado about the same length with a Honda 40 for RYA PB2 courses. Low fuel consumption and will still plane with 4 persons on flat water.

[Dan Gurney]

Prolly not relevant but RYA national centre at Cumbrae use 60s on all their XS550s (think they are 550s, certainly feel pretty beamy) and they do ok 4 up.

[benjytaylor]

So as a safety boat/Rya level 2 craft 50/60hp 4stroke should be fine?
I'm just thinking the 50hp would struggle with 4 up in any moderate sea conditions.
I have been looking at mercury/mariner 60hp efi

[RIB-Teccie]

I've used one with an old mariner/ yammie 60 twin, performed fine. If it is a 4 stroke 60 hp would be my choice.

[chris.moody]

Originally Posted by benjytaylor

So as a safety boat/Rya level 2 craft 50/60hp 4stroke should be fine? I'm just thinking the 50hp would struggle with 4 up in any moderate sea conditions. I have been looking at mercury/mariner 60hp efi

You are correct, it would really struggle in any waves. The SR5.4 with the 50 and the Tornado with the 40 are used inland so never see waves more than a foot high, and usually it's "smooth". If using a SR5.4 in coastal waters I would want a 70.

[Searider]

A photographer chap on the IOW uses an old 5.4SR which had a 60hp Yam 2 stroke. Seemed to go OK.

[whisper]

Hi Ben,

I'm sure that Avon used to say that the minimum recommended hp for the SR's were:

SR4 - 25hp
SR4.7 - 40hp
SR5.4 - 60hp

However Zodiac have now removed these from the web and replaced them with recommended power:

SR4 - 40hp
SR4.7 - 50hp
SR5.4 - 80hp

But the Max hp have remained the same:

SR4 - 50hp
SR4.7 - 70hp
SR5.4 - 90hp

The links seam to be broken on the Zodiac page but here's a link to the milpro catalogue:

http://zodiacmilpro.com/ZodiacMilpro_Catalog.pdf

[benjytaylor]

Cheers whisper!
60hp it is then. Now to find a cheap 4st if anybody knows of one?

[whisper]

Originally Posted by benjytaylor

Cheers whisper!
60hp it is then. Now to find a cheap 4st if anybody knows of one?

I know of a cheap 60hp 4 stroke, but I won't post it on here in case it causes a bit of a frenzy

[Ovey]

Queue the influx of PMs to Whisper's account!

[Boatnomad]

Old 5.4 specs............

[9D280]

Blairvadach outdoor centre used to run one with a Yam 60.

Cumbrae had one with twin 30s. It ran ok-ish if you weren't in a hurry when one engine packed up.

[whisper]

Originally Posted by Boatnomad

Old 5.4 specs............

40 to 85! Wow! A 40's small with a flooding hull...

[Crusher]

I realise it's all cost....but better to have a few spare horses inlet the lid and not need/use them, than to be shy a couple when you might just need it most.....
And unless you are very heavy with the hammer a larger engine not working as hard as a smaller engine pushing it at the same speed won't drink any/much more motion lotion...
Just a thought........

[benjytaylor]

Originally Posted by chris.moody

The one I use is a club safety boat and for that purpose it is ideal with a 50. I also use a tornado about the same length with a Honda 40 for RYA PB2 courses. Low fuel consumption and will still plane with 4 persons on flat water.

Hi Chris,

So realistically if I was to keep the hull capped on the sr5.4 I could get on alright with my Yamaha 50 4s for a club safety boat

[SPR]

I use 50 Yammie 4 on my bombard 5.5 - does what I need and cheap to run!

S.

[chris.moody]

Originally Posted by benjytaylor

Hi Chris, So realistically if I was to keep the hull capped on the sr5.4 I could get on alright with my Yamaha 50 4s for a club safety boat

On flat (ish) water inland a SR5.4 with a 40 or 50 4s would be fine as a safety boat. For coastal work in bigger waves it would be a bit underpowered.