Rib/engine rating

Garry B · 01 February 2016, 16:53

Hi, I have a 4m Sea Rider and have replaced the old 50hp outboard with a newer 40hp four stroke with trim and tilt, the engine appears to be too heavy for the boat as there is a tendency for water to swamp over the transom when stopping even when being cautious. is it possible the engine is too heavy for the boat? what could I do to prevent this happening.

Searider · 01 February 2016, 17:22

Has the transom been cut down?
It should be straight across the top.

Garry B · 01 February 2016, 17:33

Hi,
It isn't straight across the top so yes it must have been cut down

matt h · 01 February 2016, 17:34

Which engine is it and where are the fuel tanks/ consol location etc

matt h · 01 February 2016, 17:35

Thats a part of the issue then

beamishken · 01 February 2016, 20:39

You could block the flooding hull to allow the boat to sit higher at rest
Plenty of older 4 m boats are short shafts so not a problem in itself but obviously with the Sr flooding hull it reduces the freeboard
Lots of boats will ship water on shutdown if your not carefull you just need to come off the plane slowly or blip the throttle just before the wave comes over the transom

Poly · 02 February 2016, 19:33

Quote:

Originally Posted by beamishken

You could block the flooding hull to allow the boat to sit higher at rest

But that will probably have minimal impact on "pooping" (when your stern wash comes back over the transom after you stop.

Garry B · 02 February 2016, 19:58

Thanks Guys for all your comments, Blocking the holes in the hull had crossed my mind however there is a dean hole in the back of the boat which drains in to the space below the deck and then out of the large hole at the back.
May have to exchange for a different boat.
Thanks again for all your comments.

beamishken · 02 February 2016, 22:28

Just block the drain hole there should be an expanding plug to do it and drain via elephants trunks
Seems a bit extreme to change the boat for a fairly minor problem
We run a 38'hard boat and can flood the decks on that if we power off too hard
As poly says not much going to stop it other than being carefull

willk · 02 February 2016, 22:48

Quote:

Originally Posted by Poly

But that will probably have minimal impact on "pooping" (when your stern wash comes back over the transom after you stop.

That was one of your more informative posts Poly and it's cleared up a bit of confusion for me - or at least I see the stern talking to that I got from Mrs willk in a different light...

spartacus · 02 February 2016, 22:50

Speaking of old 2-strokes...

Occasionally Yamaha 50hp long-shaft 2-stroke outboards come on to the market. In this case (if the seller is to be believed) as part of friend's estate.

The Yamaha 6H4 40hp and 50hp are arguably the finest 2-strokes ever built, and if you're lucky enough to have owned one (I had a 40hp on a Zodiac Pro) you'll never look back. They use 3-cylinder blocks, and if well maintained will serve you well.

Ignore the seller's grossly inaccurate weight calculation. These engines weigh approximately 70kg+ depending on model.

You could always reinstate the transom to full height if you're handy, or ditch the 4-stroke.

Yamaha 50HP Outboard.. | eBay

cgoing · 03 February 2016, 02:23

I 've run a number of Searider 4m with Honda 40 hp four strokes with no issue at all.

Daibheid · 03 February 2016, 10:25

An easy fix I have on an old Cobra that was never designed to carry a 100 hp four stroke is a pair of thick rubber flaps cut to closely fill the gaps in the transom. I'm talking about 15-20mm thick rubber. They're screwed to the outside of the transom and have enough "give" to allow the engine pivot and the trim to work fine. They're not 100% as good as a raised transom but I was amazed at how effectively they'll keep water out while drifting in chop or stopping suddenly.

In second place, I've seen some RIBs fitted with a GRP well inside the transom that's big enough to clear the engine swinging and tilting that simp,y funnels the water back out the low transom. I helmed , I think a Delta ( they never had much buoyancy at the stern, especially with a bunch of divers gearing up), years ago that had something like a heavy piece of tarp made on to a S/steel frame to form a similar inboard well. Looked jury rigged but worked for years. Maybe a cutout fertiliser sack, a broom handle and some double sided tape might allow a proof of concept test?

In third place I've a Ribtec that had the transom reinstated by a very substantial piece of sheet S/steel folded into a "U" to neatly fit over the transom and bolted on. The engine at least the top two bolts is secured to that doubled over plate. Reinforcing plates are common on RIB transoms but this is the first one I've seen making up the transom and it works a treat both structurally and to keep the sea where it belongs.

Cautionary notes are if you go with a solution that leaves the engine at its current height I never leave my engine off and down if drifting in chop as the lower exhaust port could allow seawater wash up into the lower cylinders. I know that happened on at least one F115. So beware mooring if the stern could be presented to chop.

If on the other hand you go for raising the engine/ transom, check first where the cavitation plate will sit first.

Whatever your solution, be aware the boat will be tail happy heading into waves, use caution in steep waves or where you risk getting air even -at sub planing speeds. Get the battery and fuel tanks as far forward as you can and carry spare fuel, anchor, dive weights etc in the bow.

You've a nice package, work on getting it optimised rather than filing for an expensive divorce!

Daibheid · 03 February 2016, 10:33

"But that will probably have minimal impact on "pooping" (when your stern wash comes back over the transom after you stop."
That sounds messy Poly. I've had a few scares at sea but I'll only admit to almost pissing myself. You make a strong case for never tucking your pants into your sea boots☺️