Ballast Requirements (Boat Weights)

[Len Morris 2Participant @lenmorris2]

Hi Ashley,

Thanks for that.  The best stuff I know is the silicone used to glue fish tanks together.  Transparent, high modulus and readily available in small repair tubes or large construction cylinders from local aquatic shops.  Best of all is that it specifically states it’s fish friendly once set.  They might all be when set but only the fish tank goo states so.  Very pond friendly.

Len. 🙂

[Richard SimpsonParticipant @richardsimpson88330]

John, Just something you might find interesting regarding a suitable hull for your plant.  The hull below was made from a plan that was included in a model magazine in the early 60’s, called the Wide-A-Wake.  The plan was specifically designed to accommodate the Stuart Turner D10 engine and a Stuart Turner boiler.  I fitted my hull with a Hemmens Caton ‘V’ four engine and boiler.

I chose to work to a scale of 1/6th to enable the wealth of figures and accessories that are available to be used to detail the model.  I can’t remember the length of the hull now but you get a good idea from the shot on the workbench.  Its around four feet long.  That is a perfect size open hull for the Stuart D10.

[Ray Wood 3Participant @raywood3]

Hi Richard,

Classic beauty , I always worried the the two guys in the stern were more than friends ??

Rum B*m and Baccy 🙂

Regards Ray

[Richard SimpsonParticipant @richardsimpson88330]

Funny you should say that, it was also mentioned by the ladies in the tea tent on the day.  I did question their overly fertile imaginations, I put it down to something in the tea, or boredom, and since then the gent steering has been sat down!

I think the hammer hanging from his belt was giving misleading signals.

[Ray Wood 3Participant @raywood3]

🙂

Thanks Richard that is a relief !!!!

Vision’s of the Gavin & Stacey fishing trip were never too far away ! But so funny 🙂

Regards Ray

[Richard SimpsonParticipant @richardsimpson88330]

Brilliant  🙂

[jcbryantParticipant @jcbryant]

Richard,

Thank you for the suggestion.  She’s beautiful, and I especially like the 45 gallon drum with the hand pump, the bloke in the overalls, and the tools strewn about.  A nice riposte to the usual image of Edwardian elegance.  But nice as she is, she’s not exactly my cup of tea.  Were I to build an open launch, I think I’d want something more along the lines of the 1/12 hull offered by Orion.  But as it is just 9″ wide, I don’t think that my steam plant would fit in it.  Just looking at the plant in my present hull, I think that 12″ of beam is about as low as I could go without having things look silly.  And to preserve the proportions of the Orion hull, this would require building a 64″ long model.  Ow!  In any case, plenty of food for thought, and I’ll have plenty of time to think while I work on getting the tug into the water as an electrically powered model.

– John

[Richard SimpsonParticipant @richardsimpson88330]

The oil drum is actually hiding the gas tank.

[jcbryantParticipant @jcbryant]

Just a quick update lest anybody be curious.  I’ve done a quick test on the fit between the hull and the superstructure by putting little blobs of plasticine every four or so inches and pushing the two parts together.  The results were as expected.  The fit isn’t very good at all.  While some of the blobs were pretty well flattened, others weren’t compressed at all.

I do think that it’s possible to make an argument for the concept.  In particular I like the fact that the entire interior of the hull is readily accessible.  But it’s obviously essentially that the joint be well thought through and constructed (a parallel with hatches on submarines comes to mind), and unfortunately the builders didn’t meet this bar.

The original two screw down points were hopelessly inadequate as a means of bringing and holding the two parts together, and I’ve now added three more – two towards the bow and one in the centre at the stern.  This is still totally inadequate if one is thinking in terms of compressing a gasket, but it’s a big improvement, and at least the connection is now sufficiently robust that foam in the superstructure could be used to provide buoyancy of last resort.

It has crossed my mind that, with an electric motor, most of the interior of the hull is just empty space.  Pretty well all of the space not occupied by ballast, the (lead acid) battery, and the motor could be filled with foam, and if this were done the hull would not sink even if it flooded completely.  The motor would cease working early on in the flooding process, but I could get around this problem by building a sealed box around the motor and the stern tube.  And doing so would reduce the hull’s ability to take on water to practically nothing.  So even if the hull/superstructure joint proves to be irredeemable, I think that the tug can at least be made pond worthy as an electrically powered model.

The full size Joffre had what I assume are scupper doors in her bulwarks (five on each side).  On the Caldercraft model these are very prominent, but in photographs of the actual tug they are subtle to the point of almost being invisible.  And they are certainly very subtle indeed (and definitely non-functional) of my model – basically just very shallow depressions on the bulwarks.

I assume that I need to make at least one pair of doors functional, as otherwise any water that makes it over the bulwarks in simply going to remain on deck.  Though there are a couple of hawse holes on either side, these are relatively high up in the bulwarks and a long way from the lowest point of the sheer.  One thing that surprises me is that on the drawings of the Joffre in Phil Thomas’s book the bottoms of the scupper doors appear to be significantly above deck level.  Can anybody explain how this worked?

 

 

[Richard SimpsonParticipant @richardsimpson88330]

What you are referring to are generally known as freeing ports and you are quite right, they are for clearing water from the deck quickly, in the case of waves coming over the bulwarks.  Generally I would expect them to be fairly close to deck level.  Maybe not necessarily at deck level as when the majority of the water has been cleared quickly by the freeing ports the scupper system can cope with the remaining water.  The scuppers usually being a drain channel that runs around the edge of the deck with scuppers fitted that are nothing more than drain pipes to clear the water overboard.  Having the freeing ports too high up the bulwarks doesn’t make much sense so that may be a less than accurate drawing.

I do agree that most freeing port doors are hardly noticeable on many real vessels as they usually actually fit flush with the outside of the bulwarks.  Many kits, such as the Caldercraft one, have doors that are glued to the outside of the hull, which is perhaps not the most accurate representation.

[Dave ReedParticipant @davereed72029]

The motor would cease working early on in the flooding process

Hi John, Both brushed and brushless motors can function completely submerged at the voltages your likely to use. The components that would need protecting are receiver, speed controller and rudder servo. Waterproof speed controllers and servos are available (possibly receiver as well, depending on brand).

The motor would need thorough drying / lubrication after (eg WD40) but it should still get you home if the hull is still floating!

Obviously if you swap to steam, a submerged boiler isn’t going to work too well.

D

[Colin BishopModerator @colinbishop34627]

Is there no possibility of ‘cleaning up’ and remaking the joint? For example levelling off the unevenness along the top of the hull and topping it off with thin stripwood to provide an even base for a thin gasket. Any remaining gaps under the stripwood can be filled.

Also doing something similar to the top if at all possible.

This might raise the height of the hull slightly but not so much as to be noticeable.

Is it the hull or the top that is most uneven or are they both bad?

Colin

[jcbryantParticipant @jcbryant]

Colin,

The top and the bottom are definitely quite different.  The hull side looks quite good at first glance.  Nice and smooth and even locally, but made up of separate pieces of plywood and not a smooth curve.  The superstructure, on the other hand, has to be microscopically fair as the deck is made up of a single piece of wood, but the deck/bulwark joint is more than a little messy.  One is a nicely paved road that gently undulates up and down while the other is a magnificently surveyed gravel farm track with a rutted surface.

I can see adding bits of wood where the two sides are really far apart, but of course one can only assess the fit when the two parts ore together, and in this case one can’t see anything!  The ideal way of doing things would have been to match the bulwarks to the hull and then add the deck, as this would have rendered the joint visible.

At this stage I think the only practical way of getting a good fit is to coat the hull with some kind of release agent (wax, waxed paper, cling wrap, or whatever), lay down some form of bead (epoxy with filler or silicone), put the superstructure in place, and wait for things to harden.  I was originally thinking of epoxy, but have since come around to the idea of using silicone.  The final result wouldn’t be as durable, but the process would be a lot less messy (and far more reversible if things go wrong!).

– John

 

 

[Colin BishopModerator @colinbishop34627]

That is certainly worth trying as you could remove it if necessary – epoxy would certainly be messy as it is much runnier, the silicone will be easier to apply and would stay where it is put. Excess can be wiped away along the joint.

In an earlier post, Len Morris suggested the type of sealant used for aquariums. The type below is a high modulus  (firm) type intended for marine applications and aquariums and comes in black.

HA6 Marine Silicone Sealant

There are alternatives from other manufacturers.

Colin

[jcbryantParticipant @jcbryant]

Colin,

Epoxy doesn’t have to be much runnier.  I’ve a filler material that I can mix in with it to make it pretty well as viscous as I want, and there’s a bonus in that the final product is easier to sand than pure epoxy.

Thank you for the sealant recommendation, but the only source I can see for it is ebay.ca, and the actual seller is in the UK and “may not ship to Canada”.  I’m going to have to find something that is readily available on this side of the pond and that has similar properties.  Happily there are lots of choices, but the task is somewhat complicated by the fact that the term “high modulus” is not in general use over here (if I simply look for something with “high modulus” on the label I’ll be looking for a very long time).

– John

 

[Colin BishopModerator @colinbishop34627]

John,

Try your Canadian yacht chandlers, they should have a range of suitable silicone sealants for marine use. Whilst high modulus might be preferable the standard medium grades would probably be perfectly adequate for your purpose.

Alternatively check out aquarium sealant such as this:

https://www.jlaquatics.com/asi-aquarium-silicone-10oz-black.html?srsltid=AfmBOoprHo71xoyMzRPaH0DuU68G2m3rvUDsZoYPn1vjX-vrbvxOBWuU

The advantage of silicone is that it will still be flexible when set to give a good seal. Epoxy won’t. It’s a rigid resin glue rather than a seal but you know that.

Colin

[jcbryantParticipant @jcbryant]

Colin,

If i simply use either epoxy or silicone to make the two halves match perfectly, there are going to be places where there is no epoxy or silicone at all, and there is instead direct wood to wood contact.  In this case it doesn’t really matter whether the material is resilient or not as there is not going to be any compression anywhere.  In this case one is simply depending upon the quality of the fit.

To gain any benefit at all from the flexibility of silicone, one would have to first make the two halves match perfectly (and I think that epoxy would probably be the best choice here) and then lay in a uniform layer of silicone.  One issue is that this would raise the superstructure by the thickness of the silicone layer, and another is that there would probably not be any significant compression of the silicone except in the immediate vicinity of the screw down points (the superstructure simply isn’t all that rigid).  And then there’s the little matter of just how one could create a uniform layer of silicone.  I’ve some ideas on how this might be done, but on balance I’m not sold on the whole approach.

Thanks for the link to the aquarium sealant.  It looks good and there are multiple sources.

– John

P.S. The flexibility of silicone is also a drawback.  In the course of launching and recovering the tug I imagine they’ll be lots of times when I want to simply put the superstructure down somewhere.  Just how long is a silicone seal going to tolerate this kind of thing without degrading?  Epoxy, on the other hand, will stand a lot of abuse.

[Richard SimpsonParticipant @richardsimpson88330]

The more I read about this project and get a feel for the amount of work that is going to be involved in resolving this hull joint issue, coupled with the additional internal work involved with adding foam, bilge pumps or any other water ingress alleviating measures, the more I think the best course of action is to revisit the idea of cutting the superstructure off to make a more normal deck access.  Even the idea of having a number of screws to hold the hull together isn’t the best of ideas as there may well be an occasion when you need quick access to resolve such an issue as a speed controller bursting into flames etc.

Originally I understood the reluctance to tackle removing a section of superstructure as the work was going to be substantial but I suspect that now you have far surpassed that with dealing with the hull joint, which is still going to produce a less than safe or satisfactory result.  I would bite the bullet and look at how the superstructure can be made removeable.  A lot of work but at least you will end up with a seaworthy model.  Part of the thinking might also be to make the decision that steam is simply impractical in this model so going down an electrical path only might make the job significantly easier.  You may even be able to consider removing only the engine room cover to give access to the electrical bits and pieces, simplifying the job even further.  I understand that sometimes we hate to admit defeat with a direction we have set our minds on but we can then be in danger of becoming blind to easier alternatives that might give us a better result.

Having read through this again this morning and realising the thought processes that have gone into the flooding mitigation aspects I can’t help but think that this hull joint needs permanently sealing and making good and an alternative deck access arrangement needs re-investigating.

[jcbryantParticipant @jcbryant]

Richard,

Thank you very much for your comments. They are greatly appreciated, even if you haven’t got me convinced.

Even if I could modify the model along the lines that you’re suggesting by simply waving a magic wand, I’m not sure that I’d want to do so, and in practice making the changes would obviously involve considerably more effort (to put things mildly).

One issue is that I don’t fancy lugging the tug around with all required ballast in place.  Rather I envision dropping much of the the ballast in after launching.  And obviously getting ballast into the appropriate places would be a lot more difficult (if not impossible) if it all had to go in through superstructure and engine casing openings, particularly given that, assuming a steam plant, one opening would be largely filled by the boiler and the other would be largely filled by the engine.  Keep in mind that at best the superstructure opening would be only 1″ wider than the boiler (i.e. 1/2″ on either side), and that with steam and exhaust pipes in place, the engine is a pretty snug fit for the engine casing.

And, yes, there is a definitely an elegant solution to this particular problem.  Ideally all of the ballast would take the form of water tanks.  These would get filled with pond water (either by natural flooding or pumping) after launching, and would be emptied (using either a pump or compressed air) prior to haul out.  But something like this would need to be planned from the outset, and isn’t really a possibility given where things stand now.

And how about the rudder servo and indeed the entire rudder linkage arrangements?  As things stand now (hull/superstructure joint) everything is completely accessible should I ever have to change the servo or make other changes.  But were I to permanently attach the superstructure to the hull and go with just two openings, everything would become complete inaccessible.  I do realize that normal practice is probably to extend the linkage (assumed to be good for ever) so that the servo can be accessed through an opening, but I don’t see this as a viable option for me.  Quite apart from the fact that with the steam engine in place it would be difficult to find space for the servo, I want to be able to replace the rudder with a larger one should it prove inadequate, and in order to replace the rudder it is necessary to be able to get to the top of the rudder post.  A removable section of some form at the stern isn’t a viable option and even if it were, just how many separate joints can one have before one comes to the conclusion that perhaps just one big joint isn’t such a bad thing after all?

In general I think that a “two opening” solution and a steam plant are almost certainly mutually incompatible.  Save for the rudder issue, an electric installation would be feasible, but if steam is going to be ruled out, surely simply largely filling the hull with foam is a much easier way of dealing with probable water ingress than engaging in a massive rebuilding project?  And should by some miracle it proves possible to make the hull/superstructure reasonably watertight, I’ll retain the option of giving the steam plant a shot.

I might add in closing that making the superstructure removable would be a major job.  Just thinking about it makes me shudder.  Just to mention one little issue, two of the stay wires for the funnel terminate on deck.  They’d have to be made detachable, and so on and so on.  And of course one would have to make the joint reasonably watertight and devise some way of holding the superstructure in place.  It would be a nightmare, and in comparison improving the hull/superstructure joint (and installing a bilge pump) strikes me as a relatively trivial exercise.

– John

 

 

[ashley needhamParticipant @ashleyneedham69188]

I hate to suggest it, but if you have a low freeboard, just sail on calm days!!! We have a few models here at Bushy that really only like the calm.

Not ideal, but perhaps practical. Did anyone mention a bilge pump,???

Ashley

[jcbryantParticipant @jcbryant]

I will definitely be starting off with calm water (and with a float and a length of line sitting on deck!).  A bilge pump is definitely in the works, and I’ve just received a small electric pump that I ordered.  I’ve tested it and it looks very good.  The flow from the outlet is impressive, and it emptied a small pail in very little time.  I’ve no trouble at all in believing the claimed flow rate of 1.3 litres/minute.

I realize I’ve absolutely no chance of producing a perfect seal, but if I can restrict the inflow of water to less than 1.3 litres/minute I should be fine, and I think that this much should be achievable.

I thinking now of using silicone to create a good fit between the two halves and then adding a thin soft rubber seal (weather stripping) that will be stuck to one side and that will easily conform to the other.  It’s not as if there’ll be any pressure to speak of behind any water trying to get it.  Basically all I have to do is create a barrier that doesn’t leave any openings for water to get through.

– John

[jcbryantParticipant @jcbryant]

Some finishing touches remain to be dealt with, but the projected bilge pump is now in place.  As the pump I’m using is non-submersible, I’ve mounted it as high as possible.  It wouldn’t do to have it fail as soon as the hull begins to flood!

The suction end of the arrangement includes a non-return valve and a screen to filter out debris.  The circuit board visible in the pictures will eventually be occupied by components that will turn on the pump whenever there is water in the bilge. Water will be detected electronically, using an as yet uninstalled probe.

On test (next photos) the pump emptied the container of water in about 25 seconds.  This works out to about 1.25 L/min, which corresponds very well with the pump’s specified 1.3 L/min.  And the jet of water coming out of the through hull fitting was most impressive.

I’m now pretty confident that the pump will be able to deal with whatever water does get past the hull/superstructure joint.  I do accept that the joint seal won’t be perfect, but my expectation is that the leakage is unlikely to amount to much more than a bad drip.

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