1956 steel hull roamer question

[fiftysixer]

I own a 1956 35' steel hull Roamer that currently has 1989 rebuilt 350 gas crusaders with 90 hrs on each and two 98 gallon fuel tanks. The hull has been replated and the boat weighs in at 18,000 pounds.I was tossing the idea around of trying to make it into a long range cruiser ( i don't know if it qualifies as a trawler). I boat lake erie and do alot of 1.5 to 2 mph trolling for walleye. Would it make sense to repower with diesels to try to gain fuel economy or should I just slow down and putt with my gas motors?

[gonzo]

If you are planning on putting say over 3000hrs a year, it may make sense. In four or five years you would break even

[apex1]

Trolling with a Diesel is a nono, it kills them! Except you have CPP (controllable pitch props). The so named "trolling valve" in some gearboxes is just a sort of emergency solution, it wastes part of the power instead of turning the prop.

Stay with your petrol engines as long as the fuel is affordable. and then another season............

Regards
Richard

[fiftysixer]

Trolling is a must, so I guess that will weigh heavy in my decision. Thank you for the input. I am not worried about cost of 'breaking even' although I understand the theory. I am more concerned strictly with the MPG math. A couple other questions.

1. Is my boat under powered with twin 350's @ 18,000 pounds?

2. Can I get similiar range as a diesel trawler if I putt at 7 or 8 knots or is it better to get my boat on plane and stay around 2000 rpm (which is about 15-19mph.)?

3. What is the MPG difference between diesel and gas for a boat like mine both for cruising on plane and 7-8 knot range?

[FAST FRED]

What is the MPG difference between diesel and gas for a boat like mine both for cruising on plane and 7-8 knot range?

A diesel IF installed with the proper loading may create 16- 18hp per gal of fuel.

The gas engine is not subject to underloading hassles so should make 10- perhaps 12Hp on a gal.

12 hp would be a very modern fuel delivery and very new engine system.

Slow is always cheaper 5 or 6 K will not be that expensive , the bigger waves you make (faster) will cost more fuel.

Measure the fuel flow , guesstimate the Hp you are using and compare what the same Hp would cost in diesel.

Remember to be efficient the diesel will be far smaller ,( say 60-75hp for proper slow speed loading) so the boat will NEVER be a plaining boat again.



FF

[apex1]

1. Is my boat under powered with twin 350's @ 18,000 pounds?

That is impossible to answer seriously through the net without having many more parameters than just displacement. But I tend to say it is´nt.

2. Can I get similiar range as a diesel trawler if I putt at 7 or 8 knots or is it better to get my boat on plane and stay around 2000 rpm (which is about 15-19mph.)?

In general a planing hull will provide the best compromise of speed / range / consumption at low planing speed.


3. What is the MPG difference between diesel and gas for a boat like mine both for cruising on plane and 7-8 knot range?

Let me refer to the first reply above.


Lets face it, you have no Trawler, and trolling with a planing hull is not efficient. But with the petrol engines you have already the cheapest compromise for the required service.
You cannot "convert" the boat into a displacement vessel by changing to diesel and running at displacement speeds. That speed range is´nt efficient with your hull. And as mentioned you would kill the engines quite soon, and / or have a service bill to make you cry.

Stay with what you have, you´re at least not far from a optimal setup.

And thanks Fred!

Regards
Richard

[fiftysixer]

Thank you all for your time. This is the beast. 36353

[apex1]

Nice boat!
Though I have my doubts that she is really planing?!? That is a typical "semiplaning" vessel, very common in the Netherlands and north of Europe. What is your max. speed with the 350hp engines (in knots, not miles)?
When my assumption is right (and I´ll bet on that), you do much better in terms of economy at displacement speeds. Around 7-8 knots I guess, will be a low consumption speed.

Regards
Richard

[fiftysixer]

I have owned the boat for less than a year. The fastest I have pushed her was 28.8 knots @ 3100 rpm. I feel I could go faster but you can literally watch the gas gauges move at that rpm.

Roamer Boat Company was based out of the Holland, Michigan. Chris Craft bought Roamer in 56' (which my boat is 1956). My title says Roamer not Chris Craft as the manufacturer. I don't belive Crhis Craft changed the hull until 1957.

This link has info on Roamer Boat Company. If you click on (35) you can get specs. [/URL] [url]www.geocities.com/alloyed2sea/History.html (www.geocities.com/alloyed2sea/History.html)

This is my first 'big' boat adventure ( if that is not obvious) and all information is greatly appreciated. Does this change the opinion for diesel motors if initial repower costs are taken out of the equation?

[apex1]

No 29kn IS planing there is no doubt! So the statements made above remain valid imho.

Even when you could get the diesel engines for free it is not sensible (from a economical point), you do´nt save money, you would waste it. The diesel does not stand trolling well! The present setup pushes her to a more than sufficient top speed, and allows trolling til the cows come home without any harm. You can putter around half the year on one engine at 3 kn almost at idle. So, for which reason should you change anything?!?
Do some tests at which speed she runs best. Most boats give you the best of both worlds a tad above the hump. Means when she came on plane. You said 15- 19 kn @ 2000rpm, so try to throttle back until she falls back in displacement mode, lets say thats 1700rpm, then your optimal speed would be around 1900 I assume (in terms of economy). At displacement speeds she does not do so well, you´ll burn more fuel for the mile than at low planing speed!

And do´nt get me wrong, I am not a advocate of petrol engines in a boat. In fact I would never install any in a boat I build or sail! And if the engines and the fuel were for free I would´nt!!!
But here I think you should leave it as it is. Honestly...

Hmm it was not clear that this is your first big boat adventure, there have been others here with much dumber questions or statements on their 3rd or maybe 5th boat, feel comfortable.

Regards
Richard

[fiftysixer]

Thank you. I will run tests next year for winter is upon us here in Cleveland and she will be shored and winterized in 6 short days.

For the mean time I will go watch grass grow in my backyard. It will be good training for when my dream of traveling the Great American Loop in a full displacement trawler @ 7knots comes true!

[apex1]

Hmm, all the best for watching the grass...:D

Is there a speed limit on the great loop? Is there a offshore part in it? Otherwise you have a boat to do that trip!?

Regards
Richard

[fiftysixer]

My point was to learn patience..lol.:)

The great loop is a 7500 mile trip (12,070.08 km) that goes through the great lakes, south down the Mississippi, through the Gulf Of Mexico and around Florida, north up the Intracoastal waterway to New York and Canada, back to the great lakes. 6 months to a year. For me it will be a retirement thing to follow the weather about 30 years from now. http://en.wikipedia.org/wiki/Great_Loop

Short term goals are to make small trips in Lake Erie from my port in Cleveland. There are islands about 80 km from Cleveland. I would like to travel back and forth a few times in the summer to start my experience into passage making.

Petrol is around $3.00 (U.S) for 3.78 liters. I need to figure out the most cost efficient way to get the fiftysixer to the islands and back. $400 - $500 a trip is not acceptable. I am patient, so slow speeds are feasible if economical.

[apex1]

30 years is sufficient time to get the sealegs and to have a economical passagemaker built or bought I guess.

Good luck, and let us know how she does!

Richard

[rawebb]

I have been researching steel roamers, especially the 56 fters, and would like to know others opinions [the pro's and cons] of this specific vessel.