Boat question (Full Version)

All Forums >> [Casual Banter] >> Off the Grid



Message

Owner59 -> Boat question (8/14/2008 1:51:04 PM)

Two actually.


Is it possible or practical to retrofit-install Styrofoam or similar floatation devices in to an older boat?

And, is running two smaller outboards,at say 115 or 125HP, a lot more to run than a single 225 or 250 motor?

Thank you in advance.



bipolarber -> RE: Boat question (8/14/2008 2:58:45 PM)

Not enough info... what kind of boat are we talking about?



corysub -> RE: Boat question (8/14/2008 5:07:57 PM)

Don't think it's a problem to run two motors.  They are in sync with each other and you have a hell of a lot of power back there.   If you are going to run far offshore I think it might be a good idea from a "get the hell out of here" aspect should the weather change suddenly,to having back-up power if one engine should fail.  I had a little 23 foot Mako and got along great with just one 235 Evinrude.  However, I never went more than ten miles offshore.  There is also the question of the cost of gasoline to consider, unless, of couse, you are a goggle stockholder and little things like gasoline cost don't matter.




wulfgarw -> RE: Boat question (8/14/2008 7:26:35 PM)

As to the first question, yes, most smaller boats can be refitted with foam in the bilge and stringer/bulkhead spaces.  A small hole is drilled and the foam is injected, and it's rather inexpensive.  Things to concider are drainage, mildew buildup, and acess to wiring, fuel lines, steering/throttle linkages and even the stingers and bulkheads themselves (presuming traditional construction)  I personally would prefer a bilge to foam.

As to the second. your larger question should be what will this boat be used for?  Fishing, diving, SAR, skiing?   Offshore, (assuming the vessel is rated to handle twin engines with a large enough transom to accomodate the extra size and weight) I would go with two for the redundancy, and you'll also have 6 blades (again assuming) on two pushing water rather than 3 blades on one.  (ways to go faster in the water, more blades,3 being typical of small craft, bigger/higher pitched blades or spinning the blades faster until they cavitate.  Smell what I'm cookin?)  I'd rather have 2 downrated engines running cooler than one egine overheating.  Inland, I would go for one to save money (2 engines = x2 maintenance) and shore isn't very far off so redundancy shouldn't be an issue.  Unless you're on the great lakes, which I would treat as oceangoing.  So, yes, running a pair is going to cost more, but should pay off in longer engine life,

If you could give us more info, maybe we can help more



Daddysredhead -> RE: Boat question (8/14/2008 7:43:15 PM)

Dear me, when I saw the topic, I thought it said, "Bloat question." 

Signed,
PMS girl 

*sighes and giggles*



Owner59 -> RE: Boat question (8/14/2008 8:10:47 PM)

 
Thanks so far to everyone.

It` a 21 foot center console,no motor.

I wanted a Boston Whaler b/c they don`t sink.Same w/ Edgewater.



But I got a '91' Starcraft,pretty clean and ready to repower.

It`ll be a commuter, for short trips to work and for running errands.

I`ll occasionally be going into the big blue,so an unsinkable hull and two engines would be the best layout.I`ll have sea-tow insurance but don`t really want to be stuck out in the ocean.

So I`m considering  twin counter rotating screws,if it`s not to expensive to run.

It makes sense that two smaller engines would use more fuel than a larger one at the same horse power.But how much more is my question.



corysub -> RE: Boat question (8/14/2008 8:42:38 PM)

chuckles...Daddysredhead....just too cute....  



cjan -> RE: Boat question (8/15/2008 5:34:10 AM)

Owner, two are better than one because of the redundancy/safety issue as has already been stated. New engines, still under warranty, shit the bed now and then. When you are offshore, even with tow insurance, redundancy and spares in all your vital systems is the key to safety, besides prudence, of course.



wulfgarw -> RE: Boat question (8/15/2008 9:53:49 PM)

Owner,
You didn't specify any particular brand or type, but I found some comparative data on Mercury EFI 4stroke outboards.  At max throttle (6040rpm) a 115 hp on a Starcraft 170SF  in fresh water fuel consumption was 10.4 GPH.  Back it off to 5K rpm and consumption drops to 6.3 gph and 4K rpm and fuel use is at 3.8 gph.  It would stand to logic that you could back a pair off on RPM and get better fuel economy and performance than one at max rpms...  It seems that 115HP is the max that that line goes.

http://www.mercurymarine.com/look_deeper/boat_house_bulletin.php?ID=221&SortBy=Title&Section=outboardChecks&fourStroke75115=12

A 250hp Mercury Optimax 2 stroke on a Invincible V-bottom has a fuel consumption at max RPM (5800rpm) of 41.2 gph, and 19.2gph at 4K rpms. 

http://www.mercurymarine.com/look_deeper/boat_house_bulletin.php?ID=351&SortBy=Title&Section=outboardChecks&optimax200250=7

So, at first blush, it would appear that you would use LESS fuel running a pair for almost the same performance as a single large engine.  But then, I'm not a nautical engineer and would reccomend talking to a maritime mechanic or dealer for better info. 

Mercury Outboard's website - http://www.mercurymarine.com/index.php

Is this more of the type help you were looking for? 




PanthersMom -> RE: Boat question (8/15/2008 11:57:51 PM)

boat.....hole in the water you throw money into.  got rid of ours not long after his dad gave it to us.  too much hole, not enough money!
PM



Owner59 -> RE: Boat question (8/16/2008 12:16:17 AM)

quote:

ORIGINAL: wulfgarw

Owner,
You didn't specify any particular brand or type, but I found some comparative data on Mercury EFI 4stroke outboards.  At max throttle (6040rpm) a 115 hp on a Starcraft 170SF  in fresh water fuel consumption was 10.4 GPH.  Back it off to 5K rpm and consumption drops to 6.3 gph and 4K rpm and fuel use is at 3.8 gph.  It would stand to logic that you could back a pair off on RPM and get better fuel economy and performance than one at max rpms...  It seems that 115HP is the max that that line goes.

http://www.mercurymarine.com/look_deeper/boat_house_bulletin.php?ID=221&SortBy=Title&Section=outboardChecks&fourStroke75115=12

A 250hp Mercury Optimax 2 stroke on a Invincible V-bottom has a fuel consumption at max RPM (5800rpm) of 41.2 gph, and 19.2gph at 4K rpms. 

http://www.mercurymarine.com/look_deeper/boat_house_bulletin.php?ID=351&SortBy=Title&Section=outboardChecks&optimax200250=7

So, at first blush, it would appear that you would use LESS fuel running a pair for almost the same performance as a single large engine.  But then, I'm not a nautical engineer and would reccomend talking to a maritime mechanic or dealer for better info. 

Mercury Outboard's website - http://www.mercurymarine.com/index.php

Is this more of the type help you were looking for? 




Yes ,exactly.

Thanks,friend.



windchymes -> RE: Boat question (8/16/2008 4:50:53 AM)

quote:

ORIGINAL: Owner59


I wanted a Boston Whaler b/c they don`t sink.Same w/ Edgewater.






They said that about the Titanic......[:D]



cjan -> RE: Boat question (8/16/2008 7:56:12 AM)

quote:

ORIGINAL: windchymes

quote:

ORIGINAL: Owner59


I wanted a Boston Whaler b/c they don`t sink.Same w/ Edgewater.






They said that about the Titanic......[:D]


Actually, sinking is quite rare, especially in smaller power boats...unless, of course, you forget to put the transom plug in before you trailer launch. I've seen it happen more than once.

I also once pumped a coupla gallons of gas into the  rod holder of my brand new boat instead of into the fuel tank which was placed too close to it, imo. Shit happens, especially if one has had a few brewskis. [sm=chug.gif]



windchymes -> RE: Boat question (8/16/2008 10:29:57 AM)

Still.....saying "it won't sink" is just like asking for it, lol.  [;)]



Page: [1]

Valid CSS!




Collarchat.com © 2025
Terms of Service Privacy Policy Spam Policy
0.015625