Building an aluminium OSRV for Barbados

[Bajansailor]

I had mentioned recently on a thread about wind farm support boats about how I am currently involved in a project with Alnmaritec who are building an Oil Spill Response Vessel for the Oil Terminal here.
AndieMac and Kawasaki have asked for some more details, so here are some drawings and photos showing progress to date.
The hull form for this vessel started off as a basic Wave Worker type (more info about them here at http://www.alnmaritec.co.uk/class_worker.html ), and then subsequently evolved over about 6 months into the drawings shown below as a result of close collaboration between Alnmaritec and the Oil Terminal, with a bit of input from me.

Here are a couple of side profile drawings :

While here is a plan view on the main deck :

And here are bow and stern elevations :

Here are a couple of construction photos from August showing how the hull frames were set up on the jig, with longitudinal frames subsequently added :

And here are various photos emailed to me as pdf's by Alnmaritec showing progress since August :

I took some photos during my visit to Alnmaritec last month, and will post these tomorrow.

This vessel will be based at Oistins, on the south coast, and one of her main duties will be to lay the oil boom around tankers that are loading crude oil for export to Trinidad - there are nice coral reefs and beaches immediately down wind of the tanker moorings, and this is a preventative measure in case they have any accidental spills while loading.
She will also be comprehensively equipped to tackle oil spills if / when they do happen, including 20' long outrigger booms port & starboard for spraying dispersant.

On the propulsion front she will be fitted with 2 x 150 hp Cummins 4 cylinder turbocharged diesels on conventional shaft drives with the propellers and rudders well protected by full length skegs.

 

[AndieMac]

Thanks for the post....how long till launching?

She looks sturdy and up to the task.

Is she built at that length to suit the more easily obtained skippers tickets, cowswain for us (up to 40 feet).

 

[Bajansailor]

Calum, launching date is supposed to be at the end of February, but it will probably be early - mid March now I think (through no fault of Alnmaritec - rather, they had delays in receiving equipment from their suppliers) - which is fine by me, as that will give the weather some more time to warm up a wee bit!

Re her length, there was no consideration of rules re tickets for the crew (as there are no rules here, even for commercial craft) - rather, it was more about what was the minimum size vessel we could have with enough deck area for stowing the boom reel while taking into account stability considerations and having sufficient working space for carrying out other oil spill tasks.
And hopefully she might just squeeze into the lift out dock here with literally millimetres each side....

Here are a few photos I took when I visited Alnmaritec last month :

Firstly, here are some of the front end - the foredeck is cantilevered outboard, a bit like an aircraft carrier in a way, in order to get maximum deck space. This should also (I hope) reduce the amount of spray flying up.

Here is a view on deck looking forward - the wheelhouse was just plonked temporarily on deck, and has not been properly aligned yet.

Here is the deck plating being installed forward of the starboard hull stowage locker :

This photo shows how a watertight bulkhead is stiffened :

This is the bottom shell plating in way of the port transom :

Fairly massive engine beds :

Engine room hull framing :

This view is looking inside the bridgedeck between the hulls :

One of the two Cummins 150 hp diesels waiting to be installed :

And finally, here is a trial fit of the above engine - lots of good access all around!

 

[Kawasaki]

Brill Banjan
Thanks, I found that very interesting

Like the bit about 'no rules'!!

I would be interested to know what speed She hopes to make.
Plus what gearbox reduction and props will be married to the twin Cummings.
Cheers
K

 

[Kawasaki]

Just followed Your link to Alnmaritec.
So forget My last questions!!

That's it.
No work done now
Looking at all sorts of ally boats now
THANKS MATE!!!!! ?? -!

 

[Bajansailor]

Re the expected speed of the OSRV - everybody will be happy if she can cruise at 8 knots, however I reckon that with her more pointy bows (when compared against other Waveworker hull forms) and relatively slender dory type displacement hulls she should be able to do 10 knots quite happily.
I think that the gearboxes are 3:1 reduction, and the props will be 4 bladed - don't know what the diameter and pitch are.

Re the Logistics supply boat ALN 094 built for the Chinese - http://www.alnmaritec.co.uk/all_boats90.html - copied below are a few photos of her.
She was being packed up on my last day at the yard, getting ready for taking her by road to (I think) Felixstowe where she would be shipped to Shanghai.
Alnmaritec must be very competitive on the world market if they can export boats to China, when everybody else is importing vessels from the Chinese!

She has rather slender assymetric hulls as shown below :

Here are a couple of photos of her water jet propulsion units :

Here is one of the vent boxes for the starboard engine room :

And here she is being lifted on to the low loader that would take her down to Felixstowe :

The crane is a standard container carrier - looks like a big tractor with an extendable arm and adjustable straddle bar for lifting containers.

Here is a wee fishing cat that was in for a re-fit - I think she was being converted for use as a personnel transporter (maybe in the wind farm sector).

And finally, here is Alnmaritec's brand new CNC plasma cutting machine - after manually arranging optimum usage of the plate re nesting the frames, it cut out all the hull frames for the OSRV, including all the wee radiuses wherever there were any sharp angles to avoid hard spots and possible stress cracking later on.

 

[Kawasaki]

Ah, that last post has explained something
Cos the drawing had alluded to shafts
I trawled the Sight
And could not find a match to the Vessel!
Gearbox and prop details will be annuled if She is driven by Jets!

 

[oldsaltoz]

.
Could be some fun walking in that deck in the tropics.

Can you tell me what drove the decision to install turbo charged engines as opposed to standard of perhaps 2oo HP?

 

[Bajansailor]

Oldsaltoz - Agreed re walking in bare feet on a bare aluminium deck in the tropics! But the crew of this vessel will always be wearing boots (and life jackets!), so they won't have to worry about getting their feet burnt.
The Kayak Kat that we built here 9 years ago has a painted deck (without 5 bar treads), and that works well, but then they are carrying bare-footed tourists and they have to try and keep the decks cool (its a cream off white colour). And they do have to re-paint the deck occasionally.

And I agree with you re naturally aspirated engines rather than turbo-charged - I am not too sure what did drive the turbo-charged decision in the end. But I am looking forward to the sea trials, and seeing what sort of speed she will achieve with 300 hp on tap.

 

[AndieMac]

Seeing the CNC cutting machine, reminded me of the West Aussie company that sells plate alloy boats in flat packs, just like Ikea furniture.

With the lean towards plate alloy, in certain recreational and pro. fishing (6 to 10 metre) circles, eg. large trailables, and the relative ease of finding good welders/fabricators, along with the spartan requirements of these craft, I understand they have been moving a fair bit of stock.
The fabricating/welding company would market the finished product as their own particular breed, and it seems a bit of a win win situation.

Some have tried to improve the ride of the (light) plate alloy by increasing the deadrise of the hull, and compensate the at rest tenderness from the deep V, with a floodable keel or water ballasting. The rear lower section of the transom is permanently open, so when the boat comes to rest, water floods into the keel and stabilizes the roll, and simply flows out as soon as forward movement is applied.
The principle was used by a Kiwi GRP builder (Smuggler boats) 20 years earlier.

 

[Neil_Y]

So that explains it, you went for jets in the end! I'd looked at the long shaft line and props on the drawings when I sent the PM.

The only problem with Al boats is that the factory is too bloomin noisy, there always seemed to be lots of hammering going on, when we were there.

 

[Kawasaki]

Banjan
Couple of things confuse Me
Yep
Taint difficult I know!
You mention that there are no rules ref Skippers/ length etc for Commercial craft
In reply to-- AndieMac, I think

But you have posted elswhere about Skippers liability in the Caribean or thereabouts?

The Drawings of said craft show shafts
But the piccies are of Jets?
I looked on the Builders sight that You so kindly gave
Could not marry the craft to the description there also
Am I losing the Plot!?

Not trying to cause a prob Mate

Could be the cold here shrinkin me brain!

 

[Kawasaki]

So that explains it, you went for jets in the end! I'

EH!
What explains it?

Bleedin more confused now!

 

[Latestarter1]

Engine choice

.
Could be some fun walking in that deck in the tropics.

Can you tell me what drove the decision to install turbo charged engines as opposed to standard of perhaps 2oo HP?

Now I am an arm chair engineer and not bang up to date, however I stuggle to think what is considered a "standard 200Hp" engine. Turn the situation on its head, you are consultant drawing engine spec together, needs to be in current production and if over something like 170Hp has to be IMO Certified, what would be your choice?

 

[Neil_Y]

Sorry Kawasaki, we worked with Alnmaritec on this boat last year
http://www.alnmaritec.co.uk/boat_aln084.html The Port of London Pilot boat, which was fitted with Seatorque drives....when I first saw Martins designs (above) as others have noticed it was on conventional shafts, and could have also used Seatorques, but the final choice seems to have been jets.

Does that help?

 

[Bajansailor]

Oooops! Oh dear chaps, my apologies for confusing you, it was not intentional (really!).

Our boat for Barbados (the OSRV) is ALN 096 and she is still under construction (there is no mention of her yet on the website) - they have just put the bulwarks on, and I will hopefully be receiving some photos soon showing the progress since I was there before Christmas.

The above photos of the red / yellow cat with the water jets are of ALN 094, which Alnmaritec built for China. I included some photos of her on my last visit to the yard in Blyth as she was being loaded up on the low loader.

Our boat still has 'conventional' shaft drives as per the drawings posted earlier.

Kawasaki, re the issue of Skipper's Liability, I think that was posted by Tradewind Sailor (?). There will be no requirements here for the skipper or crew to have any tickets to operate the OSRV.
However if she was a 'speedboat', for example a wee Boston Whaler or Fletcher that can do over 15 knots, then a speedboat driver's license would be required by the Operator / driver.

Re the engines chosen, I understand that these basic 4 cylinder Cummins engines have been around for a long time during which the basic design has not changed (much) - these were what Alnmaritec initially proposed.
We did consider other makes of engine as well, as there is no proper Cummins dealer here as such, but the same could be said for all of the other popular engine manufacturers.
There used to be a fibreglass fishing boat builder here who were the Agents for John Deere, and there are a lot of JD's in fishing boats here now. They were considered as the PLA cat (mentioned by Neil above) has them, but in the end everybody agreed to go with the Cummins engines shown.

PS - I agree with Neil re the amount of noise generated when working aluminium! When cutting and grinding operations are going on you really do need ear protectors. And those Geordie welders are tough - the temperature inside the shed must have been only just above 0C. Although one of the welders was telling me how he was getting rather hot when doing overhead welding when inside the (not very deep) bridgedeck, lying on his back stitching the deck plating to the frames.

 

[Latestarter1]

Engine choice

Considering the displacement of your vessel power output appears to be spot on as this is ISO 8665, proper HP.

4BT150 has been around since 1987 or so, plenty of time to iron out any wrinkles, and was clean enough to certify for IMO NOX. Bit of a "rough diamond" and on the expensive side, lot of motor for 150 Hp, but super robust with inexpensive parts.

I am still pretty close to two installations one in in a Cornish 10 tonne rule beater and the other was a marine unit converted to run hydraulic bow thruster in a sand dredge. Hundreds in marine gen sets in service. The engine installed in the crabber has now passed 12,200 Hs. Failed lift pump a thermostat around 5,000 hs and required new raw water pump and and heat exchanger overhaul at 7,900 Hs. Blowby at 7,900 was perfect!

The 4BT in the sand dredge was a nightmare to install. Head, oil pan and exhaust manifold had to come off to go down through deck hatch. Motor was re-assembled down below. Although maintainence has not of a high order, over 22,000 hours on the clock at last major survey, two starters and cracked exhaust manifold due to overheat since new. Requirement to overhaul at next interim survey.

Weak points; the Sherwood GC5 raw water pump, body material is poor, at anything over 6,000 hours pump performance falls away even with new impeller cam kit as the body wears. Cummins uses some sort of water based paint, way inferior to Volvo, enviomental thing, engines look old before their time.

Purchase new Sherwood pump and Fleetguard filters as part of ships gear and life will be good. Thinking about it 4B used to call up smaller lube filter, somthing like Fleetguard LF3344 at a guess. Do not start sceaming at first service when none are available. 4 & 6B engines share the same filter head NOBODY has ever used the correct 4B filter, was supposed to be smaller and cheaper. However did not work out that way as everybody stocks larger far more common LF3349, generally no more than $9 U.S each, far cheaper in bulk.

 

[Kawasaki]

Banjan Neil
Thanks for all that
Now clear!

All very interesting stuff
Cheers
K