SR4.7 with Mariner 60hp EFI Bigfoot

hamish · 03 March 2012, 21:43

Hi guys - does anyone know what the top speed of my Searider 4.7 is likley to be once I repower it with a 2007 Mariner 60hp 4-Stroke EFI Bigfoot i recently picked up will be (assuming its just with me abord).

The reason I'm asking is my insurance company want to know before they confirm the premium.

Also - does anyone else have this same setup who could advise me on what prop i should be fitting for good allround performance?

Many thanks!

whisper · 03 March 2012, 22:00

Did you get lucky and buy the orange one on B&O?

I reckon it will do around 33 - 35 ish, as for the prop you will have to see what the revs are at top speed.

Turbodiesel · 03 March 2012, 22:16

Prop wise, i would guess at about 15" pitch. The MoD 4.7 seariders with 60hp 2 strokes use 17" pitch, but the four stroke revs out to 6000rpm so should be about 15" ish.

Boats&Outboards · 04 March 2012, 00:03

Quote:

Originally Posted by whisper

Did you get lucky and buy the orange one on B&O?

I reckon it will do around 33 - 35 ish, as for the prop you will have to see what the revs are at top speed.

Which orange one ? Did I miss it ?

Peter @ Boatsandoutboards4sale ~ askboatsandoutboards4sale@sky.com ~ 07930 421007

whisper · 04 March 2012, 00:17

Now forgive me if I am wrong but I have been looking at this and thinking.... Could it be?

Avon RIB for sale , Avon Searider Rib - Boats And Outboards

hamish · 04 March 2012, 07:30

Ok thanks chaps. No - i didn't buy the orange one, i bought my 4.7 about a year ago. The orange SR at Retreat Boatyard looks really well looked after - can't tell if it is a 4.7 or an overpowered 4m - looks too big for that though? I may swing by next week or so and take a quick look as its only a couple of miles away for me.

hamish · 04 March 2012, 07:46

Here's the outboard i've bought:
MARINER 60HP 4 STROKE EFI BIGFOOT 2007 LONGSHAFT | eBay

Downhilldai · 04 March 2012, 19:17

Quote:

Originally Posted by hamish

The orange SR at Retreat Boatyard looks really well looked after - can't tell if it is a 4.7 or an overpowered 4m

4.7

Downhilldai · 04 March 2012, 19:20

I'd say you'd need a 17" pitch prop with a 60 EFi Bigfoot.

Top speed will be around 32-33kt

whisper · 04 March 2012, 19:31

Quote:

Originally Posted by Downhilldai

4.7

The race is on

Quote:

Originally Posted by Downhilldai

Top speed will be around 32-33kt

And the 4.7 loves to cruise around that speed

Downhilldai · 04 March 2012, 20:09

What max speed will yours do with the 70 Yam, whisper?

whisper · 05 March 2012, 16:58

I was doing about 36 but I tend to carry a lot of fuel and other kit, she has just had a full service, carbs striped cleaned and tuned etc so I'm hoping for a bit more now, but we will see.

I will say that the correct trim can make a big difference though.

hamish · 11 March 2012, 09:05

Thanks chaps. I'm hoping to launch it for a test run in a couple of weeks - will let u know how it goes ;-)

hamish · 13 May 2012, 22:20

I'm hoping to get ,y searider 4.7 on the water next weekend (if I manage to sort the Baystar issue - see other post). Attached are photos of the current prop on the Mariner 60 4-stroke efi Bigfoot (2007) I've bought and just fitted. The engine was taken off a displacement fishing boat - any help with what the various numbers mean would be great please, as i'm not sure what size the prop is (photos attached) but I'm assuming its unlikely to be the right pitch etc.. for my boat??

Downhilldai · 15 May 2012, 01:53

Looks like a 14" diameter x 13" pitch, which would be far too fine for an SR4.7.

I ran my SR4.7 with a Twatsoo 60/70 2-stroke which has (roughly?) the same L/U ratio as your Merc. A 17" pitch prop was ideal for general use with 2-4 people on board.

I'll have a look in the garage to see if I've got something more suitable, if you're on the lookout for an alternative prop.

hamish · 15 May 2012, 07:00

That would be great, thanks - sounds like I should be on the lookout for a new prop! How difficult are they to change once on the water (from a small tender) as I'm probably launching next weekend, and it'll then stay on a mooring for the season.

Cheers, Hamish.

Downhilldai · 15 May 2012, 09:41

Easy enough to change, but be careful not to drop any of the bits!

When I'm prop testing, I back the boat into the inside corner of a hammerhead pontoon and sit on the pontoon behind the boat, with my feet dangling in the water and the prop right in front of me (watch the skeg doesn't catch you in the 'nads though)