DIY Steel Trawler Yachts

[rustybarge]

Must be 10 years ago since i looked at the Bruce Roberts design site.
Some lovely designs.http://www.bruceroberts.com/public/HTML/TY485-B.htm

What do you think, nicer than Robg71's Bonito 'fifty shades of grey'........

 

[Whitelighter]

I really like robs boat , especially with the bonded windows. It's definitely modem classic.

I like these too - just different. For me it's all about the internal fit out.

 

[rustybarge]

I really like robs boat , especially with the bonded windows. It's definitely modem classic.

I like these too - just different. For me it's all about the internal fit out.

In all fairness, it's like comparing apples with oranges.
Modern Sleek planing boat Vs displacement trawler........but in the age of high fuel costs maybe it's more relevant than you might think.

 

[Whitelighter]

In all fairness, it's like comparing apples with oranges.
Modern Sleek planing boat Vs displacement trawler........but in the age of high fuel costs maybe it's more relevant than you might think.

I've never got the whole displacement fuel arguement.

I can run my planning boat at displacement speed and burn a lot less fuel, but I can't run my displacement boat at planning speeds.

I don't believe a displacement hull is any more efficient than a planning hull at displacement speed. All the tests ever done indicate the physics are the same.

There is the comfort factor, but planning roll is fixed with stabs.

 

[rustybarge]

I've never got the whole displacement fuel arguement.

I can run my planning boat at displacement speed and burn a lot less fuel, but I can't run my displacement boat at planning speeds.

I don't believe a displacement hull is any more efficient than a planning hull at displacement speed. All the tests ever done indicate the physics are the same.

There is the comfort factor, but planning roll is fixed with stabs.

Good point, i totally agree.
But for a DIY project, how on earth do you build a 50' GRP planing boat in your garden shed?
And the cost of fibreglass would be prohibitive.
You would also need a controlled environment to cure the GRP.

Whereas steel is super cheap, you can construct the hull outside, it's strong and easy to fabricate...but it weighs a ton!
Afaik aluminium cost more than double, and welding it is a specialist job...not suitable for home building.

 

[Whitelighter]

Good point, i totally agree.
But for a DIY project, how on earth do you build a 50' GRP planing boat in your garden shed?
And the cost of fibreglass would be prohibitive.
You would also need a controlled environment to cure the GRP.

Whereas steel is super cheap, you can construct the hull outside, it's strong and easy to fabricate...but it weighs a ton!
Afaik aluminium cost more than double, and welding it is a specialist job...not suitable for home building.

Agree with all that.

I would be in awe of anyone home building anything like this. I simply don't have the ability. And it suppose with a custom build you have the option to fit long range tanks etc for world cruising, which you certainly can't in a 50ft plastic boat

 

[rustybarge]

Agree with all that.

I would be in awe of anyone home building anything like this. I simply don't have the ability. And it suppose with a custom build you have the option to fit long range tanks etc for world cruising, which you certainly can't in a 50ft plastic boat

It seems that DIY boat design has taken a leap forward in the last decade, I remember the old Bruce designs with hard chine construction....they looked horrid, you would never mistake them for a professionally built boat.


The design above looks really nice, but which is copy of which: the dutch built Privateer or the Bruce design?

What is really surprising is Rob's planing steel Bonito design....never knew it was possible to build a steel planing boat!

Also showing the new planing hull, with inset tunnels. 20knots cruise was my goal, with a max 26 knots.
bare hull weight at 14,000 kg.

we have an allowed 2 tonnes for motors, shafts stern gear etc. gives us four tonnes to play with for fit out.
looking at three cabins if possible. I struggle to sometimes get to grips with drawings, will know what we have to play with at christmas when the steel work is complete.
engines are cummins 6.7l 480 ratings. the torque figures were really good for over the hump improvements on the 5.9l

960hp for twenty tons..........seems a lot for a 45' boat, that 's the problem with steel.

No weight on the website, The Bruce next size up is the 52' which weighs 45 tons.

View attachment 35769

 

[rustybarge]

Just as a matter of interest re. Robg71 steel 45' bonito at 20 tons/960 hp........(originally designed as S/D)

Best comparison in GRP Would be the St44....,11 tons/600hp/24kts!!! Or the Grand banks 42 at 16 tons/750hp/18kts.
So steel 45' boat weighs approx 5-6 tons more.

View attachment 35770View attachment 35771

 

[longjohnsilver]

I've never got the whole displacement fuel arguement.

I can run my planning boat at displacement speed and burn a lot less fuel, but I can't run my displacement boat at planning speeds.

I don't believe a displacement hull is any more efficient than a planning hull at displacement speed. All the tests ever done indicate the physics are the same.

There is the comfort factor, but planning roll is fixed with stabs.

Agree re fuel consumption. But the big differences between a true displacement boat and planing are the much smaller engine(s) and vastly increased fuel and water capacity, meaning independence. For example, Eos, our DeFever 48 has an 800 gallon diesel capacity and 400 gallons of water. We spent 3 weeks in Scilly over the summer, showers etc each day and still had sufficient water for another week had we stayed longer. And we only ever fuel up once a year which means we can choose where and how much we pay (ie the cheapest available) for diesel. And because our engines are low hp all servicing costs are reduced, as well as having a walk in engine room with almost full standing headroom and easy access to all parts of the engine.
And we have stabilisers, my partner would not go on the boat without them!

 

[oceanfroggie]

What do you think, nicer than Robg71's Bonito 'fifty shades of grey'

No, not really.

This one's layout and styling is much like a Pedro Bora. Nice boats but dark down below. Fab day accommodation but too dark and dingy imho below for a boat one is supposed to spend a lot of time cruisimg on.

Robg's looks nicer combining traditional interior with sleek timeless exterior styling.

 

[rustybarge]

Agree re fuel consumption. But the big differences between a true displacement boat and planing are the much smaller engine(s) and vastly increased fuel and water capacity, meaning independence. For example, Eos, our DeFever 48 has an 800 gallon diesel capacity and 400 gallons of water. We spent 3 weeks in Scilly over the summer, showers etc each day and still had sufficient water for another week had we stayed longer. And we only ever fuel up once a year which means we can choose where and how much we pay (ie the cheapest available) for diesel. And because our engines are low hp all servicing costs are reduced, as well as having a walk in engine room with almost full standing headroom and easy access to all parts of the engine.
And we have stabilisers, my partner would not go on the boat without them!

What engines do you have, and what's your cruise/ max speed?

 

[rustybarge]

No, not really.

This one's layout and styling is much like a Pedro Bora. Nice boats but dark down below. Fab day accommodation but too dark and dingy imho below for a boat one is supposed to spend a lot of time cruisimg on.

Robg's looks nicer combining traditional interior with sleek timeless exterior styling.

You only sleep in your cabins, dark and dingy is good.

 

[MapisM]

What engines do you have, and what's your cruise/ max speed?

Not sure about what LJS has in his e/r, but as a rule of thumb you can assume that for any given length in a full D boat when you've got 1/4 to 1/3 of the power of a P boat, it's more than enough.
In fact, it would be easy to build a D boat lighter than any P boats of similar length.
If they are actually much heavier, it's because they are a) stronger and b) ballasted - and for good reasons.

 

[rustybarge]

Not sure about what LJS has in his e/r, but as a rule of thumb you can assume that for any given length in a full D boat when you've got 1/4 to 1/3 of the power of a P boat, it's more than enough.
In fact, it would be easy to build a D boat lighter than any P boats of similar length.
If they are actually much heavier, it's because they are a) stronger and b) ballasted - and for good reasons.

I think Nigel Irens designed super light weight displacement boats, GRP sandwich construction, slim beam.
Iirc one was at the Thames royal thingy festival. The shape looked a bit weird.
They never really caught on.
With every engineering solution, comes a compromise.

Iirc about 12 mtr/4 tons/ 100hp/10 kts cruise....

View attachment 35789

 

[rustybarge]

Missed this on the Bruce Roberts site: trawler Yacht in aluminium, but in the next weight cat. Up at 29 tons/57'


http://www.bruceroberts.com/public/HTML/TY57.htm

Voyager TY 57
The client required a guaranteed 20 knots so as is our usual practice, we designed this vessel to perform at the speed required plus a small safety margin ... The results ... this Trawler 57 has now been successfully through her speed trials where she averaged 22 knots as designed and exactly as we predicted considering the power available.

L.O.A. 17.57 m 57' 8"
L.W.L. 15.55 m 51' 0"
BEAM 5.53 m 18' 2"
DRAFT (Twin tunnel shoal draft version) 1.52m 4' 0"
DISPLACEMENT (varies depending on version) 29,854 + 65,000 lbs +
POWER 250 - 1,100 HP
SHOAL DRAFT Twin Tunnel Stern ALUMINUM OR STEEL KIT or Cutting files and boat plans
This kit is available for building in Steel or Aluminum and the first version has a twin tunnel shoal draft hull designed to operate at up to 25 knots. We have now delivered the first kit. We also supplied a complete set of windows as part of the package.

.

View attachment 35792View attachment 35790View attachment 35791


Looks a bit like a Fleming 55'
IMHO......THIS is the boat to build.

 

[oceanfroggie]

You only sleep in your cabins, dark and dingy is good

Well the trend over the past 15 years has been towards bigger cabin windows and brighter cabins. It is nice to awake and be able to look out at a sunrise or scenery from the comfort of ones berth and at eye level. You feel more connected to the beauty of places boats bring us to. I am a fan of displacement trawler yachts, some get this right some don't. We modified a former flybridge boat of ours by putting large waist height windows in the transom, and it transformed the cabin. Nearly bought a Bora about 8 years ago, but disliked the dark sleeping cabins and wanted either a full beam master or aft cabin. Don't like many forward masters because of a) wave noise, and b) most don't have low FULL walk around island double berths, instead having stepped floor up to a high berth. For many once you've slept in the space and light of a full beam master or an aft cabin master it's hard going back to a forward cabin.

 

[longjohnsilver]

What engines do you have, and what's your cruise/ max speed?

They're twin Ford Lehman 135s, usually cruise at about 7.5kts, max a tad over 9, but not worth opening up and using probably 2x fuel for the extra 1.5kts.

Even the 135s are overkill, at cruising revs we're only using about 40hp from each engine.

 

[rustybarge]

Well the trend over the past 15 years has been towards bigger cabin windows and brighter cabins. It is nice to awake and be able to look out at a sunrise or scenery from the comfort of ones berth and at eye level. You feel more connected to the beauty of places boats bring us to. I am a fan of displacement trawler yachts, some get this right some don't. We modified a former flybridge boat of ours by putting large waist height windows in the transom, and it transformed the cabin. Nearly bought a Bora about 8 years ago, but disliked the dark sleeping cabins and wanted either a full beam master or aft cabin. Don't like many forward masters because of a) wave noise, and b) most don't have low FULL walk around island double berths, instead having stepped floor up to a high berth. For many once you've slept in the space and light of a full beam master or an aft cabin master it's hard going back to a forward cabin.

The problem with aft cabin boats is all the steps, it breaks up the large living area you get with a hardtop deck saloon boat where you can walk through from the saloon into the cockpit all on the same level.

I'm of the opinion that it's all about bright open living space with large windows all on one level, i'd be prepared to sleep in a tiny cupboard to get this layout.

 

[rustybarge]

They're twin Ford Lehman 135s, usually cruise at about 7.5kts, max a tad over 9, but not worth opening up and using probably 2x fuel for the extra 1.5kts.

Even the 135s are overkill, at cruising revs we're only using about 40hp from each engine.

That's impressive for a 48' trawler design!
It's amazing how a couple of kts, or a few feet can double the fuel comsumption!!

This seems to fit with something I read in an article by Andrew (?) Wolstenholme, which pointed out that, although you can calculate the hull speed of a boat by the sq. root x 1.34 formula, there will be a doubling of resistance as you go from 1x sq. root to 1.34 x sq. root. By this reckoning the most efficient displacement speed for your boat would be just over 7 knots

This 52' aluminium trawler with 450hp is a better comparison with Robg71 boat(S/D) weighs 20 tons.

http://www.bruceroberts.com/public/HTML/descriptions/Waverunner52_description.htm

LOA 15.77 m 51' 9"
LWL 14.06 m 46' 2"
BEAM 4.90 m 16' 0"
APPROX DISPLACEMENT planing 20,410 kg 45,000 lb
semi disp 26,310 kg 58,000 lb
POWER: planing 400 to 1200 hp . SPEEDS planing 14 to 30 kts
semi disp: 250 to 450 hp. semi disp: 9 to 14kts.

View attachment 35794

 

[oceanfroggie]

The problem with aft cabin boats is all the steps, it breaks up the large living area you get with a hardtop deck saloon boat where you can walk through from the saloon into the cockpit all on the same level.

I'm of the opinion that it's all about bright open living space with large windows all on one level, i'd be prepared to sleep in a tiny cupboard to get this layout.

Absolutely valid. It's all really just about personal preference. There is no right or wrong. There are pros and cons to every layout, and as the "passage of life" passes what suits somebody today may not suit 10-20 years down the road. Back to the original question, I can't see inside either, but on the outside Rob's boat looks slightly more timeless in styling. There is an exceptionally beautiful 85ft converted military patrol boat recently arrived on our home waters, she looks fantastic on the outside, but I understand from somebody who has had an interior tour that the interior layout does not live up to the exterior (ie ex military boat layout giving space to plant and equipment rather than living comfort). Eyes of beholder, etc, etc.