new 30 ft tug design(which material?)

This is a follow up to my last thread- building vs buying.

this is a Re-designed 45 ft. st tug as a 30 ft'er.

I've decided that for me, the best thing is to build.

I also never thought I'd use the words "perfect" and "boat" in the same sentence- but for me, for what I need, this is it.


rational.

1. There are not many 30 ft. true displacement tugboat designs out there- and the ones that are out there- I dislike. So this one is pleasing to my eyes. I believe it captures the true essence of a real tug boat and has the characteristics of what tug should be. Just my humble opinion.


2. I can choose any material, although steel would be the best suited- its also the hardest on my back.

3. a build keeps me motivated and I don't need to fork out all the money upfront

4. I can customize it as I go.

5. It is designed for Diesel electric or steam power.

6. twin screw.

7. *relatively economical to run.

8. smaller vessel means more realistic as a design for my needs and quicker to get on the water.

9. It has small accommodations, but huge accommodations with the houseboat barge.

stats:

30 ft. loa
10 ft. beam
3 ft. draft amidships
displ. 20 000 lbs.
power requirements- approx. 2 x 10 hp (steam or electric) and up.
approx. cruising speed 5.45 kn.
materials - FAL, Frp, Steel, Sheathed strip.
core cell, airex, honeycomb core.(using heavy laminates).
approximate bare hull costs to build- $10 000 U.S.

If anyone wants more info on it id be happy to provide it.

any suggestions (other than steel due to logistics and lower back limitations) for the material to build with?



* as compared to similar designs in this size.(especially in steam)

 

It looks pretty nautical and proportional. I can't tell if that's Terrance or Phillip in the wheelhouse. Other than a SOR and a rendering, have you done any more with the idea?

 

Just bought land to build it. Ill put a cabin on the land and use it as a seasonal place. Its located less than 1 mile from lake Huron and a small marina. so its an easy move.

It has actually taken me 10 years to get to this point. Its just a matter of material choice now.

Last winter- I did build most of the frame work in steel for the Hankinson 26 ft tug fred murphy but due to back issues I had to stop-I sold my frames props and engine welder etc. steel would be nice but...(arrrgh my back)

so this has to be in a back-friendly material such as frp, core or something like that- Im waiting for my childhood home to sell, (could take a while) but once that's done- ill have all the funds I need...In the meantime Ill start my build...once I get the cash-I can work full time on it.
so hopefully it wont be too long after that.

any suggestions for the material?. Its actually a hard choice.

Jay Benford calls out Airex on his 38 ft. x 14 ft. work tug- so I figure that could be a good choice. but its expensive- like 3800.00 for 600 sq. ft. of core at 3/4 inch thick(which is the appropriate scantlings for a tugboat)
so...plan to start the frames in September. hopefully have them done and on a strong back by oct 31st. after that its snow season so not much will get done till spring.
its a waiting game. but its will get done...
thanks for the post

 

I don't know of any building method that is going to be easy on your back. It is a bit like building a house, there are no "easy" trades involved in that, even if you don't get involved in lifting heavy weights, there is always the twisting and reaching and crawling into confined spaces. I wish you well, but wouldn't want to see this project finish like your last.

 

Thanks- me too(hope it doesn't end like that- kind of left a sour taste in my mouth and I almost abandoned my future goal!)
I cant imagine core being anything as hard as the steel build was- and I didn't even do any plating. most of the problem was the bending over and the welding positions the constant up and down on the loft floor. - there will be some of that for sure- but my wife- to-be can help me and that will make a difference.
the x-rays showed L4-L5 rubbing on bone and a bone spur to add icing to the cake. Im prepared to do the other work and pop lots of Tylenol 1 (codeine) to get me through it. Ill be alright tho.

there are other probs in steel like the rolling of plate etc. too much to get into doing that plus the tooling costs. but I sure wish I could use steel.

 

I remember seeing sheep shearers being supported by harnesses hanging from the overhead beams. You could lean over a 5 gallon bucket for some ground level projects, for instance.

 

What to build the perfect TUG out of????

I vote for Non exotic Wood and here is why. I am building a 30' x 8'-6" trailerable planning hull using # 1 grade hand picked Southern Pine. This is a quite dense wood and weights can very piece to piece. It is about the same as Douglas Fir regarding durability. My bottom and side frames are full size 2 x 4s and 1" net x 5 1/2" net. These are spaced 30" OC and up to 36"OC. The chine and bottom battens are a net 1" x 3". Cross pieces to support the deck and sole are 1/2- 2 x 4s ripped in half so measure 1.5" x 1.75". Bottom will be sheeted with 1 layer of 1/4" ply plus 1 layer of 3/8" ply total = 5/8"
The sides will either be 3/8" or 1/2" ply.

Total Lumber costs including Ply is under $600.00 plus $ 250.00 for stain and epoxy. All structural wood has 3 heavy coats of epoxy and connections are not only epoxied but have 3/8" carriage bolts-2 per joint. Very strong and water protected.

Now what do you want to spend the excess $ 9,000.00 on?
PS Each completed frame weighs 35 to 40 pounds and the whole hull will receive fiber glass on the exterior.

 

It's the repetitive motions of sanding with all the weird body extensions required to finish boat hulls that will give you the most trouble back wise in my experience anyway. I'd suggest building the hull upside down at a minimum and budget for an elaborate scaffold system to keep control over your working position. Sheathed strip involves (lots of...) light pieces and if you size your sheathing to function as a load bearing skin your wood strip "core" can be inexpensive wood. Kind of a trade off though since the money you save on the wood might be taken by the epoxy...

I do have to say - don't do it with a back as hammered as you seem to indicate yours is. Maybe buy a bare hull - no two ways around it - hull building is very hard on the back. Moe

 

Excellent choice- problem is my boat is not developable in ply. Or it would need some very fancy woodworking to get the panels to form over the slight radiused chine- Dudley dix uses a similar method.

I was favouring sheathed strip method-using MacNaughton's rules.
I had costed the hull out at around 6000-7000. not bad...
my fear is the wood core- if impacted might break rather than deflect away and disperse the impact- and its not an easy repair.

keep in mind- its going to see some work, and impact damage is a likelihood in anything except steel. But there are some other methods that are nearly as strong. honeycomb or core cell core with heavy laminates and also fer-a-lite. or even Ferro cement.

wouldn't the epoxy and glass add a lot more to the project?

I would have to use it anyway...if sheathed strip.


I have always liked local home depot 2x4's for boat building. I spent 1800.00 on a 24 x 9 ft. tug-barge style riverboat in a previous build using home depot wood- it was mega strong. and stiff

but this vessel stays in water and ice year round and MUST be very robust in construction.

I will consider it...thanks for your input- much appreciated.

 

That's actually a very good idea--thanks-consider it stolen.

 

Hi Moe- thanks for the post. and for your concerns.

I hear you- sadly and thankfully- its my last build. and I cannot buy one like it- and I cant have it built- it would eat the budget of the whole project. believe me if I thought I could achieve the results without back issues- id do it. but the costs..(shudder).

what's going to have to happen is family and my wife will have to help me... they can do some of the lifting and a lot of my back pain came from reaching for tools and plugging them in different sockets- changing the grinding/cutting disks and then lifting all the heavy frames to the worksite.

I cannot imagine steel to not be the hardest build method on my back.

the scaffolding system sounds like a plan...

and I agree- the epoxy costs get quite high- at first I thought (using the rule)that "wow- the epoxy cant be too bad since it is only two light skins per side of uni-cloth!" then I did the calcs using Gougeon brothers site. Did I get a shock..it was twice what I estimated. I figure around 30 gallons easy!ouch!

 

I built this boat using MacNaughtons rules in 2000 - couldn't be happier with the construction method.
http://www.boatdesign.net/forums/attachment.php?attachmentid=82880&stc=1&d=1374689601

I don't know why that would be and compared to other building methods (other than steel...)...MacNaughtons rule strikes me as sort of a belt & suspenders approach - really a hybrid. A strip built wood core is already a boat & the combinations of structural sheathing and internal structures make it very robust. The neat thing about hull repair is you can just replace the core with wood, re-sheath and you won't have a discontinuous stiffness issue like with typical cored construction. Also unlike structurally unsheathed strip construction you don't have to be fussy about getting damaged strips out & new ones carefully fitted in...Moe

 

very nice boat! any build pics of it would be appreciated...

do you think there would be any issues in stripping a counter stern or fantail? my guess is I would have to strip the fantail section (see the design pics) vertically and tie in the longitudinal stringers somehow...?

 

Im no expert but your design is quite a complex shape to make in any material .Strip plank plus dynel or cold moulded ply has been a preferred method for amateurs because you can stop and start between epoxy batchs .frp requires you to be on the job .Your design may not lend itself to strip but more to cold moulded strip ply 2-3 layers 200l epoxy . Designing for your hull is fairly complex steel or wood. so its all rather difficult

 

To explain the hanging harnesses used by the sheep shearers, they were actually wide belly bands and didn't seem to limit their mobility too much.