Ballast Converted Steel Lifeboat

I am considering purchasing an old steel ships lifeboat. Twenty seven feet long, forward (steel) wheelhouse has been fitted, twin cylinder Lister diesel engine. I think it would benefit from more ballast as even moored in the river it tends to roll when a person walks rom one side to the other. Working area will be inshore North Sea. Although a very fair weather sailor, unless at work which involves much larger vessels, I would welcome any advice as to the best way to ballast this small craft. Concrete has a passivation affect on steel, but dont relish pouring concrete onto something that I may want access to. Would a few well places zinc anodes welded to the hull help prevent corrosion? Are bilge keels feasable to make and fit?
Pete.

 

Has the life boat a very round hull (or champagne cup shape) and a relatively narrow beam? Is your boat used at its designed displacement? A lot of life boats were designed in such way and are pretty rollers.

Or your boat is used at the designed displacement (I mean it is in his water lines) and in this case adding weight in a ballast will only change the frequency of rolling, making the righting up faster and harder. Not very good for the stomach...a lot of fishing boats have this defect. It's dangerous to overweight a boat.

Or your boat is very "light", I mean it has not the intended weight and it is floating high above its water line. Putting ballast may have positive results.
the ballast has to be well centered on the center of gravity and as low as possible and you'll have a better righting moment. But it's not a miracle remedy for stopping rolling: round shaped boats have a very low initial stability and that can't be cured; they are rollers by design.

Another way is to have inflatable spoons you attach on the boat's sides while being at the mooring. It's effective. The spoons, by their buoyancy, stop or dampen the rolling.

The simpler ballast is concrete poured with scrap steel inside and the best of best is to make ballast pieces of 50 kg each so it can be moved or taken out the boat easily for maintenance and reparation. The steel must be protected (tar for example) and a sealant like tar poured between the hull and the concrete blocks. Water must not be allowed to go between the steel and the concrete or you'll have soon corrosion. Ballast must be very well secured: a moving ballast can sink the boat.

 

I agree with Ilan, so won't go into that bit. But for the last sentences

Yes, the zinc anodes will help to prevent corrosion, but only on the outside!!
They will not prevent the corrosion in your bilges.

Bilge keels are feasable to make and fit, but you have to consider adding structure inside to. This to take the forces of grounding, not that you intend to ground, but you never know.
Or are you refering to the piece of bulbprofile on the turn of the bilge on large vessels? I don't think that will work, to small,they''ll come out of the water and stop the rolling abruptly.

 

Thank you both Ilan and Dutch Peter. I hadn't mentioned in my previous mail that at the moment the propellor is only 2 inches/50mm below the surface, is there any loose rule that says how deep below the surface the prop. should be? The hull is riveted construction. I have no idea where the water line should be but it does look too high in the water. It was designed to carry 44 persons at a time of emergency, would this be its intentended/best waterline when loaded? I purchase the small craft today very, very cheaply, it should be a good project.
I am moored at the mouth of the River Tees, for the near future I will use the boat on the river with short ventures out to sea during flat calm only. Little by little until I understand its behaviour. The boat by the way was named "Thistle Do" by its previous owner, who fitted the wheel house etc, the name derived from the fact that so far during its conversion he said "this will do" and stopped further work.
I will certainly fit some anodes, my mooring is tidal so have opportunity to work below the waterline.
We had 2 fatalities at our club in May this year, 3 men put out to sea in a 6m fibreglass powerboat and had forgotten to replace the forward bilge plug. The boat sank maybe 300m from shore, a flat,calm,beautiful spring day, lots of people onshore but nobody noticed. The youngest 18 years old was saved, the other 2 in there fifties were not. They had been in the water for 3 hours and succumbed to the cold water. They were all very inexperienced.
Many thanks, I will let you know how things develop.

 

Peter,

2 inches is a bit on the shoal side, I think to have some efficiency from the prop you'll need a foot.
Originally these boats were not designed for inboard engines, with the changing views on Safety at Sea motor launches became mandatory, but that didn't mean the design of the lifeboats changed (at first), an engine was just fitted. That is probably why your prop is so close to the waterline.
Lifeboat is suitable for 44 persons, I know about the stowage factor that is used when calculation the amount of people in a lifeboat, and I don't want to be in one when everybody is on board!! It becomes a meatcarrier and I sincerely wonder if you can call that survival! Calculating with 44 people would also mean adding 3.3 tonnes! (75 kg p. person) and that seams a bit much.
With some measurements on the boat and the increase in draft your looking for it won't be hard to figure out how much ballast you need. Maybe even give it a bit trim aft, gives more water above the prop and looks cool (my opinion).
Good luck.

BTW: got any pictures yet?

 

Thanks Dutch Peter,
I intend to cast concrete blocks complete with handles. I will take my digutal camera and post some photographs.
Best regards, Pete

 

Peter said all. If the boat was intented for 44 people (my God...), actually it's too light as it's showed by the propeller. You have to make trials with weights and put the boat in good waterlines.

A riveted hull... how old is your boat? Riveting steel is not used since 60 years or it was a very traditionnal shipyard who built it.

Good luck. We are all waiting the pics.

 

Thanks Ilan Voyager

I believe the boat to be very old. In this part of England small craft change hands many many times and seem to go on forever. at this age now they tend to change hands very cheaply (£350), for this price I get an intact hull, a recently serviced 2 cylinder Lister 7.7HP engine and gearbox. The steering from the wheel house is not quite complete and the gear shift in the wheel house is not yet linked to the box. Moving it from its present mooring to mine, 13miles down river, would be a 3 man job. One on the tiller, one on the gearbox lever and one on the engine throttle. The wheel house itself was once a domestic heating oil storage tank, cut down, windows and doors cut out then welded to the hull.
I have fashioned a temporary throttle to the tillet position. The steeing and gearbox linkages to the wheel house will need some tinkering about. The new mooring is quite tight, fore and aft mooring, a new consideration is how she will sit as the mooring dries at low tide. If she cants over too far when dry she may damage the boats either side, the moorings are that tight.
I have a digital camera and will take pictures of the boat also of her present mooring and new mooring. How are images submitted, to you or to a gallery in this forum?
Pete, North East England.

 

Either way - upload them to the gallery or attach them with your post by using the large blue "post reply" button and then clicking the manage attachments button on the reply screen. I look forward to seeing the project you're working on as well!

 

Finally managed to upload some snaps of the steel lifeboat at time of purchase. No progress at the moment as work abroad keeps me away. Spare time fibreglass and paint of the small tender. Work carried out in garage. 3 metres long, 1.5 metres beam, any thoughts on the proper oar length required to row it?
Best regards, Pete.

 

Lifeboat has heavy wooden "clogs", bilge keels so sat very stable at low water (dried out). Very alarming roll when crossing the chop in the river mouth, tide against wind etc. Roll was very fast both ways but chop was maybe only 150mm height, ballast desperately needed.
Pete.

 

Looked at the pictures Pete, that's a classic steel lifeboat! The proper lenght of oars is about 2 - 2.5 x beam! (that's for lifeboats, for a dinghy I think it's better to keep them shorter then the lenght so they can be stowed inboard)
About your rolling problem, very likely the steel wheelhouse is causing the problem. I suggest you try the chop with some waterbarrels (50 liter each) under the floor boards, see if that helps and later replace them with led or concrete. Be sure to lash them properly!

Thanks for the updates!

 

Thanks Dutch Peter

Thanks, will try ballast when complete. Dinghy fits into back of my van so showed sales person who recommended right length of oars. Off to Redcar this morning, paint some steel.

 

Heat Exchange

Another question. Using an automotive diesel with all parts inc. radiator, would it be possible to link the cooling to a pipe running under the steel hull this way to effect a heat exchange?
Due Norway next week DSV Pelican.
Best regards to all on water, Pete.

 

Life Boat Conversion

Peter,

A lifeboat is designed as a lifeboat: to take a minimum of 40some passengers so you have to add some weight to your boat only for stability reasons. How you will do that is up to you. Pooring concrete in the bilges is no bad idea at all. You may prepare the steel first before you start working on ballasting. You can also go to your local scrapyard and buy old lead-scrap and start casting lead ingots.
This is the difficult and expensive way. to clear the job.