Gas powered trawler

Anyone cruising the Bahamas in a gas powered trawler?

Probably not, as there are very few gas powered boats out there that people would consider to be a trawler. However, there are certainly gas powered boats capable of cruising the Bahamas.

Do you have a more specific question for something you want to buy or do?

Greetings,
Welcome aboard.

As noted probably few are no "trawlers", but quite a few gasser express cruisers I would guess.


David

I have a 1985 Chris Craft 426 in freshwater top condition. Recently repowered with brand new fuel injection Mercruisers. Owned the boat for 20 years. Other than being gas a perfect boat for the Bahamas. (I’ve cruised there before in other boats) I know a vast majority of the boats cruising are diesel but considering the best boat is the one you own, just looking for comments.

It would seem to come down to fuel range, gas availability, and waiting for appropriate weather windows. How far South do you plan to go?

Ted

As long as you've got the fuel range for where you plan to go, I'd expect it's do-able in that boat. Given appropriate weather windows I'd consider the Bahamas do-able in my 38 foot Chris Craft with gas 454s in it.

It looks like a 426 carries 400 gallons of fuel, so assuming a 25% reserve, that means 300 gallons usable (which is what I figure for my 381 with 420 gallons capacity). Your fuel burn is probably similar to mine or a hair worse (newer, more efficient engines, but heavier boat). So to be a bit on the conservative side, figure a comfortable range of about 150nm on plane and around 350 miles at 6.5 - 7 kts. Good enough that if you take the initial hop to one of the closer islands (and plan to refuel there), you can make the crossing up on plane and get over there with plenty of daylight to spare.

Lots of outboards in the Bahamas thus lots of gasoline. A center console with 3, 4, or 5! outboards uses a lot of fuel so it ought to be fresh too.

Welcome aboard. I don’t see a problem with doing the Bahamas with your boat.

Recently repowered with brand new fuel injection Mercruisers.

What motor did you put in? I just repowered with a new Mercruiser, haven't tried it out yet, still in refit. My boat will be capable of 20 + knots and of course on plane, the fuel burn is wallet busting. But with 160 gallon tanks, doing a traditional 7 knot cruise, I have about 550 + miles. Basing this on my old Mercruiser removed which was less horsepower and when I got it, over propped. And it would do roughly 2 gal/hour at 7-8 knots.

Repowered with 6.2 350 hp. Cruising at 21, topping out at 27-28. Took a bunch of weight off with losing the 454. Mostly though we run at hull speed. I’ll know more on fuel burn once we get all of the Vesselview installed.

I just repowered with the very same motor 6.2 350 hp with Bravo 2 leg. My boat comes in "wet" at around 13500 pounds, what is the weight of yours. My old girl is 51 years old, express cruiser looking very much like an older Chris Craft, but isn't.

The reason I ask your boat weight is I'm trying to roughly figure out my upper end speed. You are the first person I've seen, let alone talked to with this new motor. The 20 hour break in will be painful as I will want to take it to WOT but won't.

Well now I'm really curious as to how fast my boat will go. I phoned Merc in Wisconsin about which leg to install (really wanted the Bravo 3) but during the process asked them to guestimate my boats upper speed. I heard between 33 - 36 mph.

Loaded probably 38-40g. Before I was running 18 cruise with a 23 wot. So far happy with the results.

Fuel in the islands may be delivered to where you purchase it very casually.


A Baja filter while fueling is a worthwhile addition.

rsn48 said:

Well now I'm really curious as to how fast my boat will go. I phoned Merc in Wisconsin about which leg to install (really wanted the Bravo 3) but during the process asked them to guestimate my boats upper speed. I heard between 33 - 36 mph.

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Sounds fun. When will the WOT occur? Then the numbers will be known. We get to Denman and Comox routinely so don't rock us!

I've seen a couple classic Mainship 34's with single mercruiser gas engines. 200-300hp range. Pricing out a repower I get it and the Mainship isn't really a trawler anyway.

Mrwesson, I’d be interested in hearing your input re why the MS34 isn’t a trawler. I’ve thought that since before 2010 but kept quiet.

Nomad Willy said:

Mrwesson, I’d be interested in hearing your input re why the MS34 isn’t a trawler. I’ve thought that since before 2010 but kept quiet.

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Mrwesson please explain.

I think the Mainship 34 is much closer to Downeast design than a trawler. Soft chines, full keel and ability to cruise at higher speeds than trawler/full displacement hulls. It fulfills its design criteria admirably. 34 Mainship is a nice boat.

Sailor of Fortune said:

I think the Mainship 34 is much closer to Downeast design than a trawler. Soft chines, full keel and ability to cruise at higher speeds than trawler/full displacement hulls. It fulfills its design criteria admirably. 34 Mainship is a nice boat.

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My thoughts too...but I can go with trawler as it is not so "classic" that with a flybridge it crossed into the "recreational trawler" arena.


My belief is there are "no absolute" criteria for a recreational trawler...mostly "just a look" and reputation.

We get to Denman and Comox routinely so don't rock us!

Well I won't bother you when I head to Powell River or Lund and higher. But Denman, that's another matter. If I'm not dying of old age waiting for the cable ferry to cross, I'm busy ducking the large recreational fishing boats heading back to Comox with their massive horsepower multiple outboards. So if you aren't ducking me, you'll be ducking them.

David Kimmel said:

Mrwesson please explain.

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Not talking down on a Mainship 34 I have one too. It's technically a semi displacement boat.. It has benefits over trawlers(like the ability to plane) but there's tradeoffs.

The Mainship falls inline with trawlers because they use low HP diesels but a 300hp gas engine would make the boat perform more like an express cruiser/sportfish.

That being said it's one of the only "trawlers" i've seen with gas engines mostly because it benefits from more HP.

Nor sure what the OP concern is but gas is much more prevalent (no ethanol too) than Diesel. Before Chub was built we had to buy gas from the fuel barge at Mama Rhoda Rock, even the little Islands like Sandy Point could get you 55 gallon drums of gasoline rolled down to the docks, yes a Baja filter was handy in those days, not so much needed today.

Many folks buy insurance as a diesel leak can cost big bucks .


When gasoline gets into the water is there the same expensive clean up for the sheen police?


The lower repair/replace cost of a gasser and no cost for insurance might make up for the higher fuel cost at speed?

A small gas leak would be less of a big deal to clean up, as gas evaporates much more readily than diesel. But a large leak would be worse. Probably still less cleanup cost, but much more safety risk.

From a cost perspective, unless you run a lot of hours, the higher fuel consumption of gas engines is likely to still come out cheaper. Insurance costs are probably not much different in the end, but purchase and maintenance costs are lower. However, the extra range of the same boat with diesels is nice, even if it's not cheaper to run.

As far as fuel burn at high vs low speeds, based on the numbers I've run for my boat, cruising on plane, diesels would burn about 60% of what my old tech carbed gas engines burn. Cruising at 7 kts, the diesels would burn about 40% of what the gas engines burn, as diesel efficiency scales better at low load, while gas engines lose a ton of efficiency at low load.

It also doesn't help that most marine gas engines compromise efficiency for being able to maintain durability with more simplistic control systems and in the hands of careless operators (otherwise they'd likely be higher compression, etc.)

Gas engines are created from car engines where high HP and acceleration are sales tools.


By optimizing the intake ( usually a 2bbl carb instead of a 4bbl) better low HP fuel use can be had.


Some folks have simply disconnected the large 4bbl secondarys and use a vacuum gauge . A quick $20.00 can make a big difference.

FF said:

Gas engines are created from car engines where high HP and acceleration are sales tools.

By optimizing the intake ( usually a 2bbl carb instead of a 4bbl) better low HP fuel use can be had.

Some folks have simply disconnected the large 4bbl secondarys and use a vacuum gauge . A quick $20.00 can make a big difference.

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Yup. Plenty of things can be done to make light load efficiency better than what we get from the typical marine gasser, particularly ones like my low compression carb-ed 454s. Another thing that hurts a lot of the older carb-ed engines is not having vacuum advance for timing. So the timing under light load is far from ideal for efficiency.

If I were to build the ideal marine gas engine, it would be small-ish displacement for its power output, but with a durable bottom end that can handle reasonable continuous power output. Maybe something like a 4.8 LS block as a starting point. Or even something a bit smaller if it could be made durable enough. Then cam it for efficiency, use decent flowing heads, add EFI with knock sensors, keep compression reasonably high. I'd also add EGR to reduce pumping losses under light load. Then if the peak power goal couldn't be reached as it sits, add a turbo to get there.

End result should be a little better efficiency at high power than a typical marine gasser but much better at low power.