Sailing Club Recue Boat

[javelin]

Our sailing club recently got hold of a searider 5.4m, fitted with twin 55hp evin's, a massive stainless fuel tank the full length of the center console, VHF, Fish Finder, GPS and various other bit's an pieces that we don't need on a rescue boat.

We found that the boat becomes pretty skittish above 25knts and unless in experienced hands could become a hazzard at it's top speed of 34knts.

We've made a couple of stainless samson posts for towing and we're in the process of fitting them.

We've also decided to remove one of the engines and associated gear along with all the electroinics that are not required.
We'll also remove the fuel tank and use a plastic removable tank of which we have a number spare.
(we are now on the lookout for a 4.5 to 5m rib without an engine.)

The issue is that the engine will have to be positioned much lower on the transom.
We we're arguing about how low we should go.

Should the Cavity plate be at the same level as the very bottom of the hull V ?

If so it looks like our engines are too short so we'll have to cut a much lower chunk out of the transom, (about another 100mm)

I also understand that the prop may have to be changed although I'm not sure what props we have (forgot to check today).

The boat will be used purly as a safety boat, off the east coast, laying racing marks and towing boats in and out of the harbour when required.

Any advice would be very welcome.

[jyasaki]

Originally Posted by javelin

Should the Cavity plate be at the same level as the very bottom of the hull V ?

That's the general starting point. Quite often, if you're tweaking for optimum performance, it'll get moved (usually up) at a later date when you figure out how it runs at that configuration.

jky

[Nos4r2]

Originally Posted by javelin

Our sailing club recently got hold of a searider 5.4m, fitted with twin 55hp evin's, a massive stainless fuel tank the full length of the center console, VHF, Fish Finder, GPS and various other bit's an pieces that we don't need on a rescue boat.

We found that the boat becomes pretty skittish above 25knts and unless in experienced hands could become a hazzard at it's top speed of 34knts.

Are they the old style non power trim/tilt Evinrudes? They are rather heavy so the boat is possibly significantly overweight on the transom.

Originally Posted by javelin

#

The issue is that the engine will have to be positioned much lower on the transom.
We we're arguing about how low we should go.

Should the Cavity plate be at the same level as the very bottom of the hull V ?

Yes-or up to an inch above.

Originally Posted by javelin

If so it looks like our engines are too short so we'll have to cut a much lower chunk out of the transom, (about another 100mm)

I also understand that the prop may have to be changed although I'm not sure what props we have (forgot to check today).

What does the transom look like? Does it already have a cutout? If it does and you cut it down further, you'll pull the transom under when towing.

Originally Posted by javelin

The boat will be used purly as a safety boat, off the east coast, laying racing marks and towing boats in and out of the harbour when required.

Any advice would be very welcome.

[javelin]

Yes they are the older non power trim 55's but with very few hours on them.

There is a cut out which was about 4" deep by about 18" wide.

From the bottom of the cutout to the keel is 54cm
From the mounting bracket to the cav plate on the engine is 45cm
(measured these earlier today)

I was going to cut another 100mm out of the cutout and then get a bent sheet of stainless to sandwich the plywood transom where the engine attaches.

I guess the best bet would be a long shaft 70hp but we're stuck with these two 55's.

I should add we have blocked off the draining hull both fore and aft and will fit two cockpit draining tubes through the transom at floor level.

[Pete7]

Agree with Nos you could end up with a rib that every little wavelet slops over the stern when she is at rest which is going to be quite often in sailing club. Both engines and all those bits are all valuable. Sell the lot on Ribnet (then e bay) and use the money to buy the boat a nice secondhand 4 stroke say 50 - 60 hp that will just plane but also tickover all day. You aren't going to need anymore.

Pete

[Nos4r2]

Originally Posted by javelin

Yes they are the older non power trim 55's but with very few hours on them.

There is a cut out which was about 4" deep by about 18" wide.

From the bottom of the cutout to the keel is 54cm
From the mounting bracket to the cav plate on the engine is 45cm
(measured these earlier today)

I was going to cut another 100mm out of the cutout and then get a bent sheet of stainless to sandwich the plywood transom where the engine attaches.

I guess the best bet would be a long shaft 70hp but we're stuck with these two 55's.

I should add we have blocked off the draining hull both fore and aft and will fit two cockpit draining tubes through the transom at floor level.

If I'm right then, you've got two short shaft 55hp engines on a standard 5.4m Searider with a cutout in the transom for a longshaft rather than a boat with a flat transom that has had a twin engine setup since it was new.

What I really wouldn't do is cut the transom down any further. My 5.4 transom only has around 100mm before the waterline-and my flooding hull is sealed off too. I suspect what Pete7 says about 'every little wavelet' will be correct at best and at worst you'll end up swamping the boat if you walk to the stern.

Sell the 55's.You shouldn't have any problems selling 55hp short shaft engines.Microplus 501 owners for example have real problems finding anything over 40hp in short shaft with remotes second hand.
I'd go with Pete7's suggestion of a four stroke 50-60hp long shaft too. It'll cost half to run and won't oil up with long periods at idle.

[javelin]

Just been down to work on the rib.
I double checked the transom height and the engine mount to cav plate and it looks fine.
No need to cut further.

Does anyone know how thick the deck is?
The centre console was glassed down but had delaminated so I want to screw it down with big self tappers.

Cheers

[Nos4r2]

Originally Posted by javelin

Just been down to work on the rib.
I double checked the transom height and the engine mount to cav plate and it looks fine.
No need to cut further.

Does anyone know how thick the deck is?
The centre console was glassed down but had delaminated so I want to screw it down with big self tappers.

Cheers

It sounds non standard. Any chance of a pic? Deck thickness depends where you are on the boat and there's areas that are reinforced on a standard one.

[javelin]

Well we've done quite a lot so far but have a couple of questions.

Removed both engines and associated gear.
Stripped the console and removed it along with the huge ful length fuel tank.
Removed all the wiring, cables etc.
Designed and built a stainless samson post.
Made some odd repairs on the tubes.
Removed the transom section and recut the stainless cover.
Fitted one of the engines back on.
Re fitted the tanks and console having removed all the unnecessary electronics, (gps, Fishfinder, log, depth, bilge pump)
Ran the much reduced wiring and cables. (just a VHF radio, engine electrics and cables)

We now have a spare 55hp engine

So we are now ready to start wiring up.

From the engine we have;
Pos and Neg Battery wires
Three pin plug for the kill switch/igntion
Red and yellow wire for the starter
and a single black wire running from the ignition box which we don't know what it does.
Perhaps revcounter ?

The wiring we removed was a right old mess but it appears that the main power leads ran straight to the battery via the isolator switch.
IE not though a regulator.
Does this mean that the charging ri=uns direct to the battery?

There was a very tatty regulator which all the old electronics ran off so we're guessing we'll need a reg between the battery and the VHF.

I took a few photo's of the rib today which can be seen at
http://www.southwoldsc.org/e107_plug...FRib%20Rebuild

Any further advice would be welcomed.

Cheers
Mike

[Poly]

Mike, assuming they haven't changed the colour codes at some point then you are looking at the following for Yamaha:

Yellow: +12V dc when ignition key is turned on.
Green: tacho signal
Black: ground (-ve battery).
Red: +12V contantly on (even with key off).

Hope that helps.

[Nos4r2]

Originally Posted by Polwart

Mike, assuming they haven't changed the colour codes at some point then you are looking at the following for Yamaha:

Yellow: +12V dc when ignition key is turned on.
Green: tacho signal
Black: ground (-ve battery).
Red: +12V contantly on (even with key off).

Hope that helps.

Prob not-it's an Evinrude

It's probably running the main charging circuit directly to the battery via the starter solenoid power 'in' if no-one's messed with it.
You need to fire the engine up on muffs with a voltmeter across the battery to check if it's charging.The voltage across the battery will rise after if's started if it's charging.
If the voltage across the battery goes above about 14.4v when you blip it then there's no regulator in the circuit.

[Poly]

Originally Posted by Nos4r2

Prob not-it's an Evinrude

oops - I assumed it was the engines in his profile!