Building a Steel, Fred Murphy!

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Kevin Morin
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Location: Kenai, Alaska

Re: Building a Steel, Fred Murphy!

Post by Kevin Morin »

electric tug,

I'm not looking at a scale Profile View of your boat plans, I'm not familiar with the details but I did read the posts and understand the set of variables that lead to your frustration. I have lots of metal boats, and I do think I have some experience in welded metal boats so what I'm proposing is not without some idea of a method that is proposed.

I'd like to add to your thinking time, before you give up the project by suggesting a concept not yet fully explored? This is an adaptation of some of your previous points and may not be helpful simply provided in words? I'd sketch this concept for you if you felt it was worth pursuing?

Using the engine of your choice, and the lowest gear ratio reverse gear you can buy/find/afford; run a 'main shaft' aft completely horizontal in the boat's Profile view. No angle, no down looking gear boxes, and no cutlass bearings on this shaft. The after end of the shaft will need two industrial rated high side load roller type pillow bearings to take the side loaded torque of the belt drive.

By redrawing the prop shaft/keel/ shaft log and drive assembly completely horizontal, no angle, parallel to the waterline, with the keel as a hollow box to accommodate the cog belt/poly drive drive the prop shaft as a stub shaft in the keel. A bulkhead mounted cone/thrust bearing and a shouldered shaft with retaining nut, the prop thrust and pull can be expressed on the short stub shaft and the bearing purchased from industrial not marine suppliers. (major cost savings)

The ratio of the stub/prop shaft to the main shaft only has to be 2:1 or 1.5:1 so a fairly small diameter pulley keyed to that shaft is not going to make a box keel too wide to interrupt flow to the wheel. Look at some of Bolger's huge box keels! they're much wider in section than I'm proposing and they flow fine.

So my idea is to use the marine gear, and both primary reduction and reverse as you'd already noted and to consider the cog belt/poly drive as the secondary reduction to get the stub/prop shaft down to the 4:1 you've targeted. Then using a box keel design to house the final drive and the thrust and reverse bearing, the larger wheel you want will fit under the stern. This would also allow you to drop the keel/shaft log/prop centerline a few inches (if the current lines need that adjustment?) to accommodate a 24" wheel? (and an advantage will be the prop being vertical not angled to the waterline.)

If this seems viable? And I'm not spending you into bankruptcy with my idea, And its worth further consideration, I'd volunteer a sketch of the concept to make it more of a visual proposal. Taking the shaft angle out of the design equation may work to allow spacial volumes not yet obvious in the Profile View of the Plans Package?

Let me know if I should illustrate this to help with your thinking and planning?

Cheers,
Kevin Morin
Kenai, AK
Kevin Morin

Kevin Morin
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Location: Kenai, Alaska

Re: Building a Steel, Fred Murphy!

Post by Kevin Morin »

electric tug,
I had thought when I was done posting the last idea and wondered if you'd considered a down angle, rebuilt transmission?

http://www.marinepartsexpress.com/ZF_Sc ... ZF15MA.pdf this link to a ZF rebuilder shows a gear that might allow the taller engine profile to sit lower by using the angled drive gear housing? Sometimes the engine's valve covers, alternators, air filter housings stick up' more when they're aligned with the prop shaft's angle? This idea is to explore 'flattening' the engine profile by incorporating an (down) angled gear?

This model seems to be able to handle the power you're proposing, it could give a 2.6:1 reduction and that may allow you to run the 20" wheel? I have no engine torque spec.s to explore and correlate this (or any drive) to the engine but overall this may be one possible solution to using a taller profile and higher rpm engine with just one 'normal'/off the shelf reduction gear?

One last item to mention, if you had a profile drawing of picture of the engine you're considering (?) it may be that with some creative brackets and added hoses you can relocate many of the items on an engine that make it 'tall in profile'? I've done with this with GM Diesels removing all the belt drive accessories like pumps, alternators, oil and heat exchange coolant pumps other accessories (coolant tanks) to lower positions on the engine. I often had much more transverse space in an engine room compared to the height, especially with displacement boats where the engine spaces may be directly below the cabin spaces.

Just another thought? I know I'm spending your money wildly - just using my keyboard!

Cheers,
Kevin Morin
Kenai, AK
Kevin Morin

electric tug
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Re: Building a Steel, Fred Murphy!

Post by electric tug »

Hi Kevin,
Many thanks for taking the time to write me those posts. I definitely am considering many of the things mentioned. the box keel idea is sound. I may look into that further. might even make the build easier IF and that's IF I could eliminate the 1/2" keel at that position. The 65 hp Volvo penta, which I may or may not get has a 2.4:1 reduction, and a 7 degree down angle on the gearbox.

The belt drive is a great idea as you mentioned. I like your idea of using a sort of bulkhead to deal with thrust. I was hoping to keep it all simple.

So here is my update.
I am going to continue with the build. Yesterday I had intended to take the strongback down. but for fun I lifted the frames up onto the strong back to get an idea of how she looks in 3d. Well, I guess It would just break my heart after getting my frames in such good tolerance, and |I spent probably 75 hours doing those frames. So I couldn't bear to just let it go. ive come so far now. Maybe this build is a mistake, maybe I'll get local officials who don't like the boat to try to stop me or maybe my car will die or some other factor that stops my build. but I think I just have to keep plugging away. so my plan is :

There are two mechanical gearbox type options, there is a helical gear system that Aero Dan showed me that could work, but of course, the company is in transition selling the rights to another larger company to mass produce them. they are about 699.00 U.S.
But perhaps the most practical and slightly more costly is a simple Hub City series 200 gear reducer, which does have compact close centers of 5.5"+/- this makes it practical. It adds about 2k to my build. but that's within reason without having to redesign the boat or butcher the design.

So Ill simply use the 2.4:1 reduction for now swinging a 18 inch prop, then in a year or so ill gear it down to 3.9:1 using the 2:1 speed reducer from hub city. the other thing \ have considered which surely would work is to simply move my engine back toward the forward bulkhead and then buy another 2:1 gearbox, make a faceplate out of half inch steel and weld that to the engine beds, that would be 4:1 but it would have two transmission , one that is remotely located, but still inline and I can get those used for around 1000.00 dollars but I have no idea how that would work (i.e connections thrust etc.?)

Anyway...I'll give it my best and see what happens. its pouring rain today. won't be able to do much , unless it stops. If so i'll finish putting the rest of my frames on the strong back.

cheers
Doug

electric tug
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update- Building a Steel, Fred Murphy!

Post by electric tug »

I am still at the FM. I built a huge gantry, probably overkill on overkill, but should be easily able to lift and right my boat, I just hope I don't need TWO gantries to do this. if so its going to be a wooden one next time...
I'll post some pics of the boat and gantry very soon.

I also paid half the amount needed for my engine, so I'm the proud new father to a Volvo Penta 65 hp Md30 Naturally aspirated. Develops 65 hp @ 3800 rpms and about 58 hp @ 3000 or something like that.

It only has a 2.47:1 ratio so I WILL be adding a reduction system in the future, but for now it can run an 18 inch prop I think...if I run it at lower rpms.

Gayle was kind enough to send me Dave Gerr's book on props.
I think that will be a good thing to figure out what my engine can do. But it runs really great. It is an
older model (mid 1980's?) but that's what I can afford. it still has some years left in it.

I had all the keel parts ; stem, keel, skeg, cutwater, stem etc., cnc'd but I made some big time errors in trying to scale from the plans using a digital caliper. But it is nothing that cannot be easily fixed, but I'll know that for certain in the next couple days when I weld it in.

once it is in I'll send pics of it in "progress"...

pls respond- let me know if anyone else is doing any steel boats?

electric tug
Posts: 64
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the build is still alive...

Post by electric tug »

:)

Hi everyone,
yes , the Fred Murphy finally has its keel on him.

there is a lot to do still. but I'm forging ahead.

It took a lot to get it into place but it fits quite well. there are a few gaps in the keel and frames up to an inch that shouldn't be there but enough metal to weld the frames solid to the keel and still have a 2" plating line.

Next phase is to do up the chines...
if your interested I'll post more pics.

Dan If you reading, how is the goliath build? also sorry amigo, I could not live with myself if I lost all that time and work and money by selling my frames and keel. I didn't think it would work, but it has.

off topic ; I spent the weekend on a cruise on Lake Huron. on the last leg of the cruise, an incredible storm hit the Lake where we were headed.

I could see it building for only a short time. but let me tell you, it hit with the force of a Mack truck. I knew we were going to get hit with strong winds and rain, but even I wasn't prepared for the onslaught of wind that I was about to experience.
When I first noticed the front, I saw the huge mammatus clouds developing, and I have seen these before in tornado's. so I was convinced there were going to be waterspouts.

I warned the folks beside me, most of whom were tourists, that if the conditions were right we might get to see a very are phenomenon, "waterspouts"

...funny no one even knew what that was. I had to explain they are waterborne tornado's.


anyway the ships bow flag nearly tore of the bow when the blast of wind came. It really was like a bomb going off.

I could actually see this front coming, because it formed a line of bad weather, almost perfectly straight , across the sky north to south, dividing the dark skies from the clear. and we were right on course to enter it.

Since we were headed right into that thing, I knew it was going to get nasty. I figured there would be water spouts. I didn't see any, once inside, but I'm certain there was one touching down nearby due to the way the wind was blowing. the wind went from a force 2- or 3 to a force 8 literally in seconds. I was standing on the lee deck and most people were on their way ,
inside, but a woman who was trying to reach the watertight door, got blown right off her feet and almost got washed overboard. I happened to be at the right place at the right time and grabbed her arm, or it might have gone very bad for her.

I grew up in the lake Huron and Georgian bay regions and have seen every type of storm imaginable, but this one was something special .

The way this one came up was especially scary. I have heard stories of this from Great Lakes Captains and Stan Rogers even sings of these types of storms in a song called "white squall" .

Until today I didn't believe they existed. But it almost knocked over the 365 ft vessel I was on. Try to imagine it going from a 2-4 ft chop to about a 7-8 ft chop in about 35 seconds. I am not exaggerating.

it had to be over 70 mph winds easily. it blew like that for about 8-10 minutes then slowed to about 55 mph. all the time there was thunder and lightning, and when that happened I decided it was time to head into the lounge. I won't soon forget this storm. And I don't think many others would either. Storms here on the Lakes can blow up THAT fast. I hope I'm not on the water in my FM if it ever does.

electric tug
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update: Fred Murphy! plate up stage...

Post by electric tug »

Well, I have the hull ready to plate up. I am now in the "anxiety" stage of the build.
I have the chines, bulwark cap, stringers on, shaft log and rudder tube installed, holes machined/drilled for the skeg/rudder bearing and bars, and need the templates made up to start plating. I am hoping for a September plate up.
It is incredible that it has taken me only 3.5 months to get to this stage.
I will not camber the deck, opting instead for easy straight deck beams raised 2" higher to accommodate the 2" lost in the camber on each side. thus instead of 8" of bulwark height inboard, there will be 6".

this eliminates time and money from the build. and makes plating far more simple and effective. The camber is NOT needed for drainage, although it does help, the longitudinal deck curvature without camber will naturally drain the wash through scuppers. k.i.s.s. principle in action!

hope my pic uploads work...
let me know your thoughts?

engine arrives Friday or Monday.

need to devise a way to service the engine and /or take it out if needed. something called a "soft hatch" anyone with any ideas on that?
the position of the engine makes it difficult to just lift out easily.
all the best
Doug
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slug
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Re: Building a Steel, Fred Murphy!

Post by slug »

The deck camber (not really that hard to do) makes the deck stronger, and steers water away from any hatches and doorways towards the scuppers.

Doug

electric tug
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Re: Building a Steel, Fred Murphy!

Post by electric tug »

your quite correct Slug, it will increase the strength, but to the best of my knowledge only marginally. I have plans for few flat bottomed tugs and they all have straight deck beams. It will easily double my time and costs to have them plasma cut from plate . not sure what the costs to roll "the hard way" would be but probably not cheap, time consuming to find someone to do it and I would have to make the template and bring it to them for each beam, I did think long and hard about it.do you realize that making deck camber on that deck creates compound curvature?

The camber is very low on the FM, so it seems like a lot of extra money and work for a small sacrifice. in any event the door is raised enough to prevent seawater from entering, and the wheelhouse would be watertight in any situation.

did you do any cruising over the summer?
.

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psychobilly
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Re: Building a Steel, Fred Murphy!

Post by psychobilly »

Why not buy or finance a plasma cutter, build FM and after your FM is complete, sell the plasma cutter.

Kevin Morin
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Re: Building a Steel, Fred Murphy!

Post by Kevin Morin »

e'Tug, p'bill, Cambered deck beams are an elegance of shape like the sheer of the tug here. They're not absolutely needed, but do add to the decks' lines and shape as an aesthetic and drying out as they drain from just a rain squall.

A few inches of camber in this small a build would normally be rolled or pressed not flame/plaz cut because the cold forming methods will leave the frames 'still' but cooling from a hot cut almost always results in further shape changes from contraction. If the notches for deck longs are added to the hot cut methods; most cambered decks frames become almost unpredictable- and need reforming to some minor degree due the combined heat of the arcs/camber cuts PLUS the notches for longs.

So in shallow cambers on smaller hulls (<or=30' LOA roughly) cold forming is much more reliable, usually faster and involved less expensive equipment.

The "Whale Back" shape of the deck following the sheer in one curve while having transverse curvature does form a tiny amount of compound curvature. Usually when fitting deck plates of this type, wholly dependent on the sheet sizes used, there is a very small hourglass curvature if the deck seams are transverse. If the seams are longitudinal (?) then the deck panels are slightly blubous in their length.

The amounts for a few inches of camber in this size boat are less than 1/2" in 10' transverse or less than 3/4" in 12-14' deck panels run fore and aft- assuming you're building an entire surface? ( I don't think that's the case here?) A simple method of battening these of laying plates on the the deck frames and marking from below usually gives the shapes' curves arc depths- that is the depth of the chord's curvature over the full length of the seam.

However, in most cases the house, trunk and cockpit so interrupt these surfaces (decks) that the amount of compound is never seen by the builder, each deck panel is simply fit to that given area without any fully transverse areas- and the amount of compound in the tiny fore deck is negligible.

I did a 52' steel crabber in the 1970's designed by Ed Monk (Sr.) of Seattle with owner/builder here in the Cook Inlet, in Alaska. The entire after deck area, designed to carry stacked crab pots, was cambered 4.75" in her 14 beam and was plated with 1/4" steel. The deck frames followed a 13" cup in the sheer that was 31' long with 5-1/2" deep transverse frames 2' OC and 2x2x1/4" T longs notched into the deck longs inverted. I cut them with an OA torch on a track carriage; then had to make a press frame with a hydraulic jack to individually bend them back to a uniform camber and curvature before they could become part of the ring frames for the boat.

When I decked the working surface over the crab tank and lazzarette the plates were all 4' x 10' x 1/4" and both the ends and the sides of each plate had to be curved very slightly to fit into weld seams. This Whale Back deck shape was compound but still had pretty small plate adjustments (full length curves in both directions) as long slow curves in order to fit up for welds, while the panels laid to the framing below.

I'd say this small tug would deck without much effort to these curves, given the deck is probably broken into smaller areas and not one big expanse??

Electric Tug, please don't forget the electric nibbler tool. This cold cutting AC electric tool can be found in industrial capacities to handle much thicker steel than your scantlings call for. The edge left is serrated but can be sanded dead smooth with a 40 grit flap sanding pad in a few strokes so this cold cutting sheet seam or edge tool is very much worth an investigation.

Cheers,
Kevin Morin
Kenai, AK
Kevin Morin

slug
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Re: Building a Steel, Fred Murphy!

Post by slug »

Back in the 90s I built a Ted Brewer designed 34' steel sailboat. We ( a friend worked with me on the hull ) built a home made roller and rolled all the frames and plating n it. The deck beams can probably be rolled by any good metal shop very reasonably and easily. I also bought a Milwaukee nibbler that Kevin mentioned. It was well worth the money (about $1100 ) and we were able to accurately cut plating (up to 3/16 ) right on the boat...ready to weld. I used it for 5 years and sold it for $900.
I've always believed in spending money on good tools, and selling them when I'm absolutely certain I'm finished with them. I call it cheap rent.
The good ones always go quick.

Doug

electric tug
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salvaging fred murphy project

Post by electric tug »

I was going to cut up my Fred Murphy build in May, but on a recent visit to the skeleton of the boat, I found that I do not have the heart to do this. I keep returning to the FM as the best choice for what I am doing and to be honest I miss building it, even with its flaws and my mistakes. Nothing is perfect. I think I suffer from the "prefect boat illness" it goes like this:

Statement of requirements
1. must be able to run at 70 knots while cruising on 1 gallon per hour, be ultra seaworthy in any heavy weather, deep draft able to run white water, have no complexity to the build, yet have all the systems necessary to cruise, roomy enough for ten people in 20 ft of space, yet store in my garage, cost less than 4k overall to build, be built in a week or two, and...

well you get the picture.
as they say, You cannot fix a problem unless you admit there is one.

So I have sold my big diesel engine, and accepted a reduction in my hp requirements by accepting something less powerful, and not needing a large gearbox. The idea is to cruise and occasional towing, I am not looking to tow Lakers into port or anything like that so 30-40 hp is ample with a 2.5 reduction or if possible 3:1. I have decided not to get hung up on huge gearboxes and props.

Now I am hoping people reading can offer thier perceptions of what might be the easiest options available to me.

I must move the boat to a new location by May 31st.

I have a couple options but not sure how to proceed.

1. is to move the entire boat as is, i.e. the frames, keel etc., as seen in the last pic posted here. This is expensive at around 800.00 cdn. But cheaper than starting over. It allows me to have my boat back to plate up stage very quickly. I can also correct some errors fairly cheaply. and not have to spend time building a whole new boat...

2. However, I did make some errors and the keel(i have no idea how this happened) is not straight. I know I did take the best care in welding it up, but still, it is not an even keel per se, it needs to be rolled/pressed flat again. But I did some number crunching and found that it would cost almost the
same
to build the boat again from scratch to the stage it is now, and in doing so, I can correct a lot of things and have a chance to do the things I would do differently. This means that I would have to cut up this boat and invest my moving money, back into new frames etc. only this time I would have them professionally cut. I have learned that a plasma torch with a good compressor would be in the 1800.00- 2200.00 cdn mark, and I can cut all my frames, keel etc, (and save some of my keel that is not "wavy" such as the stem and stern post) for far less than buying a plasma torch. In fact, The entire boat could be cut completely for far less than a plasma and a compressor and electricity, and it would be much more accurate since I can input the plans into rhino and have them cnc cut. Buying a plasma cutting torch for one job does not seem justifiable for a one time, one-off project.

After writing this it does seem starting from scratch would be better. I am worried transporting my framework might bend it out of fair, and not be able to be realigned. I am thinking out loud here, but wondered what others think. from reading my own post, it seems now I favour redoing the hull, fixing all my errors and doing things better the second time around,...at not much more cost than moving the present build.

in any event. I am back at it, and It wont take me long to get the boat back to plate up stage, I am guessing around end of may or June at latest. So I am not giving up yet. It breaks my heart to just cut the boat up for scrap. And it makes no sense.

hope to hear from everyone. Thanks to all who have replied since I have been gone.


Doug

electric tug
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update

Post by electric tug »

One other thing: I have decided to build the Tug with the cambered deck. I guess it wont be too much more trouble and it would look like it should...

best everyone!
Doug
p.s.
as far as buying a plasma torch then selling it, shop work is about 75.00 an hour in my area. I estimate about 6 hours of cutting time for the entire FM build. probably less...

I would still have to outlay 2200.00 or so for a reasonably good torch and compressor, when I can just as easily get the steel company to cnc all my work using the best equipment and tools, within far more accuracy than I ever could get by hand., for easily half of the costs (of a torch and compressor), in shop time...

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mrintense
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Re: Building a Steel, Fred Murphy!

Post by mrintense »

Doug,

I don't know about you, but if my boat was at the stage yours is and I cut it up, that would be the end of my building because I probably would never get back to starting it. On the other hand, having a boat in my garage, albeit not finished and definitely with flaws, gives me a reason to go out there everyday and work on it. Eventually it will get done, but not if I were to start over.

Not sure about the extent of the problem with the keel, but I have not run up against anything so far that I couldn't correct or live with. Moving it is risky, but in my opinion, cutting it up is more risky. Since it's steel, weld on some bracing before moving it and you should be good for a move.

Good luck with whatever you decide.
Carl

Crafting a classically styled Vera Cruise

Clipper Boating

electric tug
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Re: Building a Steel, Fred Murphy!

Post by electric tug »

Hey, thanks Carl.
I hear what your saying. It sure is a tough decision if I were to cut it up. I have to look at every angle. I should mention there are many savable parts; the stern post, the stem, the strong back, the gantry, the stringers, even some of the frames and the cross spalls, all can be saved, so it wouldn't be the entire boat being cut up. I had thought about just cutting out the bad stuff.
you might have a point here, if I moved it I could just cut out the mistakes and reweld in the new things, but i did a horrid job on the round bar, and I will have the shop roll the next ones for me.

what boat are you doing?
thanks for the post!
Doug

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