Is this structural ???

[WATERHAM]

The boat in question is a 1986 16' Starcraft Fishmaster. The name of the game here is More Room. I am limited in space due to the size of the boat and the fact that I use (2) 6.5 gallon portable fuel tanks. What I plan on doing is 1. adding a 25 gallon permanent tank, rearranging the placement of the duel batteries to accomodate the tank and allow easy access to both, and 2. add a kicker motor (this is really besides the point) but wanted to mention this because I will have duel pickups. On to My real question, the splashwell has to stay for obvious reasons as well as the "beam" on the top side of it that is riveted from port to starboard, but are the verticle aluminum "walls" that hold the minimal amount of foam flotation structural or can I remove these without compromising the structural integrity of the boat?
I fish the Great Lakes with this boat so it isn't drifting on a farm pond. If I can remove these I can install this tank without removing the floor, save a ton of money, time, and gain alot of floor space. This is all going to be installed by a reputable mechanic/ fab shop in the area, they came up with the idea I'd just like a second opinion

 

[DJ]

Re: Is this structural ???

They would not have an effect on lateral structural intigrity but might on vertical (strength of splashwell).

You're talking about adding a lot of weight back there. That may cause some handling issues.

 

[WATERHAM]

Re: Is this structural ???

Regarding the extra weight issue I understand that and appreciate that concern from an engineering standpoint. However, I already have (2) 6.5 gallon tanks back there so we are talking an extra 12 gallons minus the extra weight of the removed aluminum (minimum weight reduction) so I would look at adding approximately 96 lbs to the rear of my boat. As far as handling goes, I am mainly at trolling speeds (.5- 2 mph) with a 5-8 mile run to where I fish. Next Year when the budget allows (if I make another round of layoffs) I'll redo the floor adding the tank between the stringers. Should I somehow add any kind of bracing under the lateral "beam" or splashwell?

 

[DJ]

Re: Is this structural ???

Yes, I would add something vertically. Even if it's just a dowel rod of about 1" dia.

The aluminum you are going to remove is going to weigh about 5 pounds-maybe.

96 pounds is significant weight directly in the stern.

I am very familiar with the Great Lakes. I'd want as much freeboard, in the stern, as I could get.

If it were me, I'd find another place for the batteries, at least.

 

[WATERHAM]

Re: Is this structural ???

I was thinking of adding alumunum angle or stainless steel verticle bracing for structure and to give a home for the new plaeather curtain. I realize 96 lbs. is alot of weight but the pros outweigh the cons. Where would you reccomend putting the batteries? Room is sparse, you should see my tackle boxes. We walleye fish on Saginaw Bay, have you ever been up here?

 

[tashasdaddy]

Re: Is this structural ???

i would recommend batteries in the bow. to counter that stern weight.

1 gallon of gasoline equals 5.8 to 6.5 lbs.

 

[a70eliminator]

Re: Is this structural ???

I know where your coming from on the fuel issue.
I fish on Lake Erie with my 16' MFG V hull, powered by 67' 60HP evinrude
Fuel mix goes quick this engine seems to guzzle it, I always strictly adhere to the 1/3 /2/3 ration of fuel and only 12 gals leaves me out of some of the good fishing several miles off shore.
I also carry two batterys in the stern and with the 2- 6gal's plus a cooler of ice and my fishing buddy puts that transom pretty darn scarry low.
I would just get me another portable fuel tank and stick it up front or midship somewhere, I myself would never need more gas cause I'm afraid to go out 10 miles from shore on Erie.

 

[jonesg]

Re: Is this structural ???

i would recommend batteries in the bow. to counter that stern weight.

1 gallon of gasoline equals 5.8 to 6.5 lbs.

I think its closer to 8 lb per gal.
At least water is.
Is gas that much lighter?

 

[WATERHAM]

Re: Is this structural ???

Interesting fact about the gas weight (almost 2 lbs lighter than water). During tournaments we are literally all over the Bay in 1 day, if the fish aren't cooperating. Tashasdaddy, I already have 2 Deep Cycles up under the Bow Deck hooked up to my trolling motor for the river bite, but could run the main batteries up there due to the fact that the trolling batteries + trolling motor are on my boat for about 2 months a year during the Fall and Spring Walleye bite on the Saginaw River. Wouldn't it be a pain in the butt to run the electrical all the way up to the front though considering this is new wiring and splices are always the weakest link? a70, we'll be down in Erie next summer a bit, my buddy just picked up a brand new Islander 22' outboard.

 

[Mark42]

Re: Is this structural ???

.... However, I already have (2) 6.5 gallon tanks back there so we are talking an extra 12 gallons minus the extra weight of the removed aluminum (minimum weight reduction) so I would look at adding approximately 96 lbs to the rear of my boat. As far as handling goes, I am mainly at trolling speeds (.5- 2 mph) with a 5-8 mile run to where I fish. Next Year when the budget allows (if I make another round of layoffs) I'll redo the floor adding the tank between the stringers......

It might be more cost effective to add the tank to the floor now, because tanks are not cheap, and the tank that is put under the splashwell will not fit under the deck.

There are other options that might work well for your boat and fishing style. How about saddle tanks? They go against the side of the boat under the gunnels. Very skinny tanks, and they can be mounted mid-ship for good weight distribution.

Do you have space under the bow to put a tank? I did that with my MFG Niagara, really made the boat handle well. ( I too had two 6 gallon tanks under the splashwell, boat drives so much better with the tank up front now).

Take a browse through the fuel tanks available at oceanlinkinc.com and see what you can come up with that fits your spaces. Most tanks listed have diagrams, some do not, but if you take the model number and email moeller, they will send you the tank diagram in pdf format.

 

[WATERHAM]

Re: Is this structural ???

Thanks Mark for the site I will check it out. I work in the construction industry on the design/estimating side of it. You are definately right when you mention that it will be cheaper if I add the below deck tank right now and just get it over with, eliminating 1 whole project and a bunch of materials. Here's the kicker. My outboard right now is as old as me (1977 70hp Seahorse) I use it about 700 hours a season, sooner or later my motor's gonna crap the bed. So with that in mind and also the fact my boat is rated for 90hp I was going to save this year for a 90 Optimax and repower my boat at the same time doing the floor and below deck tank, fittings etc. If I had a below deck tank installed now with my 2-stroke, and then had a new motor (Opti or Four Stroke) installed next year wouldn't I have to put in a new tank at that point anyways due to contamination? By the way, I'm learning alot from you all, thanks for the input!!

 

[KewlBird]

Re: Is this structural ???

I had a 1985 Starcraft Superfisherman 16ft. and had thoughts about doing the same thing. Like others said you would want to fabricate some sort of support there if you remove those two panels. You will be losing couple of really nice sized chunks of floatation foam.

Now, here's what I think about the setup you would have....You already have 2 batteries up front and 2 in the back = 240lbs (60lbs each), with 25 gallon tank full = 175 lbs. (7lbs per gallon), trolling motor = 30lbs , fishing gear, anchors, coolers, ice = 100lbs+, just that is 545lbs then add yourself plus motor and your way up there probably close to 1000lbs. I can't remember for sure but I think the boat capacity is 6 persons 900lbs or 1100lbs total with gear and motor. If you bring couple of buddies you will be dragging and sitting way too low and will have to hope for really perfect water conditions.

I attempted to put a kicker motor on mine, a 9.5hp johnson (60lbs), and the back of the boat was low enough that water was constantly going through the splashwell holes in the transom. I'm not sure how good on gas your motor is but I was getting 12 hours of run time with 2 6 gallon tanks this included trolling and fullspeed in/out. If I were you I would keep the 2 tanks, but would remove "walls" and use that area for tackle/gear.

 

[Mark42]

Re: Is this structural ???

Kewlbird makes a good point. Check out the capacity plate to be sure that the boat will not be getting too close or over its capacity. Another issue is the weight of the Optimax 4 stroke, as 4 stroke outboards almost always weigh 60-100 lbs or more than their 2 stroke version. A very reliable 90hp 2 stroke light weight motor is the Yamaha 90 (I'd like to get one for myself, so I checked it out well). That would save 100+ lbs easy over the Optimax. If the Seahorse is a 4 cylinder, it probably wieghs over 300lbs (my '69 60hp Evinrude weighed over 300lbs). I think the Yamaha weighs about 190 lbs.

Anyway, are you sure you need 25 gallons? Would 18 gallons do? Just asking because of the weight issue.

 

[WATERHAM]

Re: Is this structural ???

Thanks for the input. You both have made great points as far as weight issues are concerned. My trolling motor and two Deep cycles come off the boat late April early May when I'm done fishing the river. My 70 Seahorse is a 3 cyl. and I do believe weighs around 280 (could be wrong). Don't get me wrong my (2) 6.5 gal. portables were always enough gas to get out there troll for 8-12 hours jump to a couple of spots (3-5 mile runs). My main issue with curent setup was floorspace (there was none). It seemed like we were doing jumping jacks around those darned tanks to net fish, or setting lines. Makes a cramped boat seem smaller. An 18 gal. tank would be sufficient and would be better than the current 13 gal. setup. so I can definately see your points (gaining more fuel, but not adding too much weight). Lightweight 2 stroke is going to be the way to go wether it's the Opti or Yamaha, havn't made up my mind. To be honest wish they still made the Seahorse it's my 3rd w/ no issues. Problem is I don't think I can count that high as far as hours go on that motor. KewBird, do you have any ideas for the supports? I was thinking of through bolting a piece of stainless steel to "lateral beam" and riveting to stringers. Sound like a good approach? I would do this in 2-3 places port starboard and middle if needed, it would also make a nice attatchment point for pleather "curtain" to hide all this

 

[KewlBird]

Re: Is this structural ???

I was trying to figure out how you were tripping over the tanks when they should be tucked away underneath the splashwell....Then I realized you had non-oem tanks that are oversize. Here's a pic of the 2 Metal OEM tanks underneath the splashwell, they are the 6-gallon versions and will fit side by side. My battery is turned sideways and you probably could do that with both.
http://syracuse.craigslist.org/boa/958161346.html that's the tanks I used.

 

[WATERHAM]

Re: Is this structural ???

Like your boat KewlBird, real similar setup to mine. Problem is with my duel batteries taking up space back there.

 

[KewlBird]

Re: Is this structural ???

Like your boat KewlBird, real similar setup to mine. Problem is with my duel batteries taking up space back there.

You should be able to turn those batteries sideways and you'll gain some space. You might have to add some supports but it should be doable. My battery went sideways and on the other side was the 2-cycle oil reservoir and I still had plenty of space to stick 2 tanks in there. Unfortunately I don't have any pictures of what it looked like underneath the splashwell. With those tanks you have you won't be able to stick both of them underneath splashwell, they are much longer than the metal 6-gallon ones.

Having those post seats vs. the lounge seats i had gave you lots of floor space. I was tripping all over place because of those seats...lol

 

[WATERHAM]

Re: Is this structural ???

Awesome input, it's been alot to mull over the last couple of days (massive overthought on my part), but very much appreciated nontheless. I think whatever approach I take weight is definately going to be a front running factor in my decision making. Structural integrity right up there as well. Seems like I have a pretty darned knowlegable support staff w/ this site. And I just need to approach this project like any others (with alot of common sense). I talked to my good buddy who works in a machine shop, he's coming over in the next couple days to take measurements for stainless supports. They will be custom welded by a certified welder (during lunchtime of course) and will add that strength to that back area as prevously discussed.

 

[Mark42]

Re: Is this structural ???

One easy thing to do is to take the boat out with some weight to simulate a full tank of gas. A few sand bags or rock salt bags (if you have a water softener) or even weights from a weight bench will do. Then move the weight around the boat to see how it affects the ride.

My guess is that it won't make too much difference.