tender for new RIB

[trellheim]

http://www.etenders.gov.ie/search/show/Search_View.aspx?id=MAY101845&ln=EN

[Goldie fish]

The Irish Naval Service Diving Section intends to upgrade its RIB. The following is the specification of the RIB required suitable for all offshore and inshore diving operations.

Boat Description

The RIB will be a heavy-duty commercial 7.5-meter rib with composite hull and aluminium topside fabrications. All deck fabrications must be sealed with dry gaskets, no silicones or sealants to be used. All fittings are to be bolted with stainless lock nuts and bolts to avoid corrosion.

The Hull will be coloured in grey with a black collar and the wording NAVAL DIVERS on the collar in with 200mm lettering near the bow on both sides.

It will be powered by two (2) outboard Yamaha F100DETL four stroke engines or equivalent.

Principle Data

Max Length overall: 7.50 meter
Max Beam overall 2.60 meter
Beam internal not less than 1.60 meter
Max Collar diameter 0.50 meters
Engine x2 Yamaha F100DETL Four stroke or equivalent
Fuel type Petrol (95)
Weight (100% fuel) 1800kgs
Fuel capacity 1 by 200litre tank
Crew 1 person (helmsman)
Cruising Speed 32 Knots approx

[ZULU]

Bit strange to have Alu A-Frames on the Rib. I know it saves weight but on a diving boat the trade off to strength given by stainless is a step backward in my opinion. Also alu corrodes like a beeotch, even when anodised. :confused::confused:

The deck fabrications requiring dry gaskets seems a bit strange also. I can see on one hand that it might be nice if you want to replace the console with a different seating arragement etc, but if your doing that kinda work on it your not going to worry about a bit more effort to remove some bondseal. :confused::confused:

THe Yams aren't my first choice. Their a grand engine but there are better out there for the same money. Might be due to parts but the other 40hp yams aint compatible anyways.

For info one F100DETL retails about $16,884

So $16,884 = Euro 10 930

x2 = 21,860euro

+ Control cables
+ Instrumentation
+ 7.5m Rib (Delta or Osprey or Tornado would be my favourites)
+ Deck fittings

= nice cheque!

Interesting to note that a 200litre tank will give about 3 hours @6,000rpm (25knots approx)

YAMAHA - F100DETL (4 Stroke) $16,884.00





Manufacturer: Yamaha
Model: F100DETL(4 Stroke)
Hours: 0 hours

Features:
SPECIFICATIONS:
Engine/Ignition/Transmission:
O/M Transom Height (mm/in) - 536 (21.1), Weight (kg) with prop. - 174, Engine Type - 16-Valve Direct Action Inline 4 Cylinder, Displacement cm³ - 1596, Bore x Stroke (mm) - 79 x 81.4, Output (kw/hp) - 100 (73.6) @ 5500 rpm, Max. Operating Range (rpm) - 5000~6000, Compression Ratio - 9.6, Scavenging - Double Overhead Camshaft, Ignition -TCI, Gear Ratio - 2.3 (30/13), Electronic Fuel Injection, Oil Pan Capacity (litres) - 4.5, Max. Fuel Consumption - 31.0 l/h @ 6000rpm, Spark Plug - LFR5A-11, Gear Shift - F-N-R, Exhaust system - Through Propeller Hub (Jet), Prop. Engagement - Spline

FEATURES:
Operation Method - Remote Control, Lubrication - Wet Sump, Starting System - Electric, Tilt & Trim Method -Wide Range Power Tilt & Trim, Prime Start™ -Installed, Engine Stop Watch Lanyard - On Remote Control Box, Shallow Water Drive - Installed, Alternator - 12V-20A (12A @ 1000 rpm) with Rectifier, Regulator Rectifier - Regulator Installed, Start in Gear Prevention - On Remote Control Box, Overheat Warning - On Remote Control Box, Over Revolution Prevention - Installed, Remote Control Box - Installed, Speedometer - Digital Meter, Tachometer - Digital Meter, Trim Meter - Installed, Propeller - Stainless Steel, Separate Fuel Tank Capacity (litres) - 24 l Optional, Emergency Start Rope - Installed

[Goldie fish]

Strange that they continue with Petrol too, given that Petrol Ribs are becoming scarce in the NS.

[ZULU]

I disagree. I think motion lotion (petrol!) is fine. On a dive boat, power to weight ratio is priority due to the gear your hauling. Diesels are just to big and heavy. Your also stuck if they break down because usually their single engined. With twin outboards, you can replace one if it goes - easily enough (Most of the time!! )

The other advantage is the engine comparment is outside the boat - leaving you with more space inside for gear, suiting up, dive ops etc.

[wat flies dies]

Couldnt do much worse...and there just around the corner.

http://www.ribs.ie/Dive_Ribs.html

[ZULU]

Excallibur ribs are ok. I've helmed a couple of them from big Diesel to twin outboard petrol. But if you step from them into something like a Ribcraft of Delta, you can tell the difference in quality and sturdyness straigh away.

By the way the navy divers had a rear console twin Yam Osprey Rib. What happened that?

[Goldie fish]

Don't forget Lencraft in Dungarvan....

[The real Jack]

Don't forget Lencraft in Dungarvan....

Lencraft are excellent ribs...I cant for the life of me understand why they didn't opt for a inboard volvo diesel.

[Victor]

The deck fabrications requiring dry gaskets seems a bit strange also. I can see on one hand that it might be nice if you want to replace the console with a different seating arragement etc, but if your doing that kinda work on it your not going to worry about a bit more effort to remove some bondseal. :confused::confused:

I think what they are saying is they don't want the thing to leak if it is taken apart and put back together again.

What is corrosion like when stainless steel is up against aluminium?

[ZULU]

I think what they are saying is they don't want the thing to leak if it is taken apart and put back together again.

What is corrosion like when stainless steel is up against aluminium?

If you take it apart and put it back together and it leaks, your not doing a proper job. Being able to properly put down sealant between fittings is a basic skill of anyone who works on boats. Dry gaskets can crimp and not get in and around sharp, small steps and curves , where as sealant squishes into them to form an effective seal. It also serves as a glue helping hold the fitting in place unlike a gasket.


316 stainless against T6 aluminum is no comparison. Stainless will win the corrosion battle every time. You can anodise the aluminum black or gray for low vis and a bit of extra protection, but it can be easily scratched off and will still not provide the corssion resistance stainless offers.

[Victor]

If you take it apart and put it back together and it leaks, your not doing a proper job. Being able to properly put down sealant between fittings is a basic skill of anyone who works on boats. Dry gaskets can crimp and not get in and around sharp, small steps and curves , where as sealant squishes into them to form an effective seal. It also serves as a glue helping hold the fitting in place unlike a gasket.

I think there is opinion out there that mastic, etc. is over used and I suspect this is what they are getting at. What will happen the world's windows when a mastic-eating mold evolves? :D

316 stainless against T6 aluminum is no comparison. Stainless will win the corrosion battle every time. You can anodise the aluminum black or gray for low vis and a bit of extra protection, but it can be easily scratched off and will still not provide the corssion resistance stainless offers.

Apologies. What happens when one metal is in contact with the other? One will become sacrificial.

[Test Pilot]

I think there is opinion out there that mastic, etc. is over used and I suspect this is what they are getting at. What will happen the world's windows when a mastic-eating mold evolves? :D

Apologies. What happens when one metal is in contact with the other? One will become sacrificial.

Careful! There is an entire corollary on the effects of corrosion due to dissimilar metals in salt water. There are many factors that need to be taken into account in the selection of materials in the marine environment. For example is the corrosion caused by Cathodic action, Electrolytic action, impurities from welding, resistance to high temperature, pitting, crevassing, staining and wether the surface of the metal is sealed enough (polished) and more! Also when to bond and when NOT to!
Saying that stainless 316 is suitable, is rather a broad term. 316 is quite poor when used in warm seawater for example. 316L is a higher grade stainless, but there are other higher grades DEPENDING on the application. For example, 316H, 321, 321H, 347, 253MA up to 904L and beyond.
Yes you are right, placing two different metals together in a chloride solution, is asking for trouble.
I just mention this, as it’s a part of what I do, and it can be a right brain twister, even when using cathodic test instruments.

[ZULU]

I think there is opinion out there that mastic, etc. is over used and I suspect this is what they are getting at. What will happen the world's windows when a mastic-eating mold evolves? :D

Apologies. What happens when one metal is in contact with the other? One will become sacrificial.

There are many Marine specific sealants out there that are only related to mastic in the way they are applied.

As Test pilot said, corrosion can be caused from many factors. But in relation to the RIB, I reckon the deck fittings are the Stern A-Frame tubing over the Engines with maybe a stong point up front for the placement of a winch etc. I have manufactured both in alu and Stainless steel. And while lighter than their Stainless counterparts they are maintenance intensive, requiring regular wash downs, barrier substances between fittings and their fixings.

Yes you can get aluminum rivets/screws etc but they (through my experience) are not worth the hassle for the requirment in question.

[Goldie fish]

This Company were the successful Bidder.

http://www.mstltd.com/

Their 7.5m is quite Nifty...