Caulking - "walking" or shaking out

[JRMacGregor]

Caulking - \"walking\" or shaking out

Hello Folks,

Do any members have experience or opinion on the possibility of excessive engine vibration causing the caulking to "walk" on an old boat.

I have an old sailing fishing boat (14t displacement, 38ft) which is fitted with a large, slow revving engine (44hp, 4 cylinder, 6 litre, idle 250rpm, max rpm 1000). The engine runs well, but its basic characteristics and the fact that the engine feet are located low on the crankcase means that there is obvious transverse "rocking" when starting and stopping.

The boat was originally built in 1911 without an engine, but is reasonably stoutly built (ex Scottish fishing vessel) with doubled sawn oak frames.

The boat has been repaired, refastened and recaulked at various times over the years (most recently in 2003), but I suspect that she leaks more after the engine has been run. I worry that this might be a cumulative and irreversible process. You can feel (and see, in calm water) the boat's hull vibrating.

In my heart I feel that a smaller, lighter, faster running modern diesel would be easier on the boat, but the engine (a Kelvin J4) is a bit of a classic in its own right, and I am reluctant to remove it.

Kelvin J4's WERE fitted in some smaller, but more modern Scottish MFVs, and are perfectly at home in larger and more heavily built vessels. However, my boat (a Loch Fyne skiff) is not as heavily built as a modern MFV or even an East Coast herring lugger.

Any opinions gratefully received.

James MacGregor

 

[Peterduck]

Re: Caulking - \"walking\" or shaking out

I think that if the caulking were moving at all, you'd be faced with such a heavy inflow that you'd have the boat out of the water PDQ. Even hairline cracks can allow a surprising amount of water in. Are you sure that it's not coming in through the propshaft gland? That would be whereI would look first. Not just when it's stationary, but when you are under way motoring.
Peter.

 

[Mirelle]

Re: Caulking - \"walking\" or shaking out

I think it would be a terrible shame to replace the J4, so this may be affecting my answer, but I go along with Peter.

We have a smaller boat with a Volvo MD2, rigid mounted, and for a very long time I suspected the engine of being responsible for repeated cracking of some topside seams (in way of a quarter berth, as it happened). A survey revealed the truth; three bent frames (construction is two bent between each grown) were cracked. Once they were renewed the seam cracking stopped.

I suspect the culprit may lie elsewhere.

 

[DRW]

Re: Caulking - \"walking\" or shaking out

Hello, I don't know about the caulking, but I can understand the vibration issue.
The folks at R and D engineering are very knowledgeable, helpful and not as expensive as I thought they would be. A new set of flexible engine mounts to take my Ford Dolphin 4cyl engine was quoted at £88 plus VAT. (Fortunately there is a flexible coupling fitted so I dont nees one of those aswell, but it is required with the flexible feet). (Try http://www.randdmarine.com/ ) It wont help getting the caulking back in, but it might make cruising more comfortable below.

I would be loath to lose the original engine. Good luck

 

[JRMacGregor]

Re: Caulking - \"walking\" or shaking out

Hi folks - thanks for the quick replies.

The boat definitely does not leak at the stern tube (a slight drip only when underway). The leakage I refer to SEEMS worse in the 24hrs after a long trip.

There is no obvious source visible from the inside of the hull, but so far I have not lifted the heavy cast ballast that lies in the bilges on her keelson. I hope that when I do I will find a more conventional source of leakage which I can deal with in the normal way (albeit between tides !).

The Kelvin people recognised the "rocking" problem with their engines and the 1930s installation documentation shows that a J4 could be installed in at least two different ways;
a) for lightly built boats with steamed frames they sold a "stay bar" with friction grip coupling, which secured the top of the engine to a special heavy frame inserted at the boat's side
b) for heavier boats with sawn frames, wider spaced engine feet (27" versus 13.5") and no stay bar were recommended

 

[Peterduck]

Re: Caulking - \"walking\" or shaking out

The seam between the garboard and the keel is the one that seems to go first, as it is under the greatest stress. A bit like the lumbar vertebrae on humans. I replied on an earlier query that the quickest way to find out where it is leaking is to haul the boat ashore while there is plenty of bilgewater inside. Once you have blasted the hull clean of weed and slime, the water will make itself obvious by seeping [or pouring] out of wherever it has been going in. If you have keel cooling pipes [not unusual on old fishing boats] you will be able to run the motor to see if that makes any difference.
Peter.

 

[Transcur]

Re: Caulking - \"walking\" or shaking out

Have you checked out the engine bearers and the bolts that fix them in? When the engine is running the bearers transmit the forces of engine reaction and drive. I have known of several cases where poor / old /loose bolts allow movement only when the engine is running.
Pete T

 

[Mirelle]

Re: Caulking - \"walking\" or shaking out

I assume that this is the boat's original engine.

Kelvin's main market between the wars was probably the installation of engines into originally enginess fishing boats. From some documentation I have seen they seem to have been scrupulously careful about it, and to have recommended and examined each installation. If the J4 has been in the boat since it was new, it seems most unlikely to be the cause of problems, but Pete's thought about the bearer bolts may well be on the money - his expertise is worth ten of mine.

 

[JRMacGregor]

Re: Caulking - \"walking\" or shaking out

The bolts securing the engine bearers (transverse) to the planking were one of the first suspects. The bolt heads on the outside of the hull are buried in white lead under lead tingles and I have not removed or examined them. But, when examining the hull interior in the vicinity of the bearers, no water ingress was seen underway or afterwards. However, I agree that this area does deserve some more investigation.

The J4 currently installed is not the first engine in the boat, but has been in the boat for some years. The first engine was a Kelvin petrol/paraffin of about 32hp, but equally bulky and heavy.

I should state that my original question about the "walking" caulking did not occur to me unaided. Older fishermen and others who knew have referred to inappropriate engines shortening the lives of some boats. Michael Verney refers to the link between engine vibration and leaks/loose fastenings.

When the first engines were put in these Loch Fyne skiffs before WW1, many were a mere 7 or 9 hp, since their initial purpose was to reduce the downtime and muscle power required in calms. It took a while before they decided they wanted power to work the boat in a wind !

 

[Richard_Blake]

Re: Caulking - \"walking\" or shaking out

A thought: you mention transverse engine bearers bolted to the planking rather than frames. IF the bearers are insufficiently connected to, or simply in between, the frames, could the slow-revving heavy person down there be rocking the bearers back and forth on the keel as fulcrum? I imagine that would stress the seams in between frames just above or outboard of the end of the bearer? I'm describing a perhaps less-than-ideal installation, I know, but I have seen it on one old boat.

 

[Transcur]

Re: Caulking - \"walking\" or shaking out

If you are sure the engine bearer bolts are OK then perhaps you need to look differently. If you can put her on some scrubbing posts between a tide on a dry day you should be able to identify seams which are wet. The antifouling will dry else where. If she has been refastened and recaulked the stopping should be good. Suspect wet seams, especially around bearers, frames and floors. You may find the cotton probably oakum needs hardening. If she has been rebuilt and refastened were the drift bolts between the futtocks also replaced? If not this could cause the leaks. If the engine feet are close together and therefore cause the rocking moment to be more apparent then it may be advisable to put in some extra floors/frames in this area to spread the load further up the hull. Pick a nice dayfor the scrub off.

 

[mandarin]

Re: Caulking - \"walking\" or shaking out

Hi to all
Came across this post when looking for Kelvin related items. Just to put you in the picture I do not have a deep water boat, mine is I think you would call it a "ditch crawler" of 62Ft. I have a J3 fitted on oak bearers sandwich bolted to the 100mmx 150mmx 8mm RSC (channel iron) engine beds which run from steel bulkheads either end of the engine room and are crossed by two more from steel hull side to side at the engine feet centres, all in turn welded to 10mm thick hull base plate. Fitted this way they are very smooth, but I can well imagine if bolted to less ridgid support the engine could cause movement in the hull. Your J4 will be producing 44 BHP at the shaft, Kelvins measured their engine output where it mattered, unlike todays engines, and you should have a 22" flywheel if you are petrol start heavier if diesel start, I cannot recall the weight but say 2cwt, which is a lot of thrust to hold down. The weight of your engine 1800lb plus so you need a good floor.
I saw a J4 last year at the Kelvin rally which had split the welds under one foot on similar setup. The reason, the engine had been bolted down on dry land, when floated the hull had flexed slightly and the one engine mounting foot needed a couple of millimeters of more shim to be level.
To get the Kelvin in my canal barge hull the builders had to increase the draught over normal by 4" to squeeze the prop in under the counter which is 21" yours should be 22".
If you decide to swop it for a modern motor let me know if you put it up for sale.
David