Possible Modification Project?

SLOWDUK · #1 02-02-2014, 04:15 PM

I bought my ’88 V20 Dual Console just before Thanksgiving and have only had it on the water 4 times since, just running around Pensacola Bay and some of the bayous feeding it. Our family plans on using the boat for bay fishing primarily with the occasional fishing trip into the gulf. Waterskiing was a favorite of mine growing up and I would like resume that as well as teach my grand children how to ski. When I described the boat on the forum, several of you noted the large heavy engine (a 630lb 2005 Yamaha 225 four stroke) as too heavy which could reduce the transom freeboard and cause water to back flow into the cockpit through the scupper drains. My limited experience so far has indicated that yes, with a couple of adults standing just in front of the engine, water starts percolating up through the scupper drains and the engine well stars filling with water. A significant concern of mine is the lower transom height in the event of waves approaching from the stern. Never one to accept unnecessary risk and always looking for another do-it-yourself project, I’ve come up with a plan to alleviate the problem. I’m asking the forum for advice and consideration. Maybe one of you has already attempted such a fix.
First, are my concerns warranted? Does the extra weight astern constitute a significant risk?
If so, consider the following modification.
I plan to design, build and attach to the transom buoyant hull extensions left and right of the engine. These extensions would be shaped so as not to interfere with the engine’s range of motion nor touch the water with the boat on plane. Measurements indicate that there is a space 30 inches wide left and right of the motor to work with. Preliminary calculations indicate that if they extend aft 24” from the transom, 4 to 5 cubic feet of volume can be displaced below the waterline with the boat at rest (approximately 250-300lbs of buoyancy). And maybe more importantly, additional volume above the water line will add additional buoyancy in the event waves approach from astern. The design will include ladders and handrails so that the extensions double as boarding platforms.
I am considering a wooden and foam design covered in fiberglass or an all aluminum design that my son, who is a skilled welder, can assist in fabrication.
There will be those of you that recommend trading in the motor for a lighter one, but I have initially ruled out that option as the motor (a 2005 with 130 hours on the clock) has considerable life remaining and I like the additional horsepower with the quietness of a four stroke.
I’m pretty much thinking out loud at this point. I have other projects higher on my priority list and I’m not in a rush to execute this plan tomorrow. But I am asking for your experience and insight on this subject.
Thanks in advance, Slowduk

smokeonthewater · #2 02-02-2014, 08:04 PM

I think you will find that you won't get as much flotation as you expected due to the weight of the added materials at the back of the boat and also keep in mind that the surface of the water curves up from the bottom of the boat on plane... not a straight line.... IF I did such a mod I think I would keep the bottoms flat with the hull bottom but honestly I think I'd be more inclined to move batteries as far forward as possible and get plugs for the scuppers.... and of course find a lighter engine OR a bigger boat

axespino · #3 02-03-2014, 05:30 PM

Maybe you could close the transom in right in front of the motor. I have two that I have done this to and it looked good. Just make sure you have enough room to tilt the motor all the way up.

phatdaddy · #4 02-03-2014, 06:12 PM

i'd close in the transom and put a bracket on it. your still gonna need to put plugs in the drains while your at rest.

spareparts · #5 02-03-2014, 11:41 PM

I've seen some Formulas and Mako conversions that had something like you are talking about. If you look at most modern "ski boats" with a European transom, they usually have added flotation on either side of the out drive(look at Four Winns boats for inspiration). Bigshrimping on here built a Potter style bracket for his Sea Craft a few years back, its on the classic Sea Craft site, maybe he will link it on here if he notices this thread. Theres some good information on there for you about building what you are talking about. Before you start such an endeavor, i have to ask if you have tried to move as much weight as you can forward in the boat?

randlemanboater · #6 02-04-2014, 04:13 PM

I have seen what you are describing on some aluminum "Jon" style boats with larger 4 strokes on them.

I addressed the issue on my boat with stoppers for the floor drains (just remember to pull them when it rains).

I have a 20" transom and have never had a wave come into the boat from the rear, into the splashwell yes, but not all the way into the boat.

I would think if you move some weight forward and use stoppers, the extra floatation would not be needed.

But, if you do add floatation, you only need to make up for about 220 to 250 pounds, 630# (your motor) minus say 410# (my motor) or 380# (old school 2 smoke).

Just my $.02.

SLOWDUK · #7 02-05-2014, 01:15 AM

Thanks to everyone who took the time to comment.
Axespino’s suggestion to close off the motor well in front of the engine is a good one that the previous owner already incorporated. He mounted a piece of starboard about 8” tall with quick release clasps to separate the engine well from the cockpit. It’s not waterproof, but will inhibit a wave that enters the motor well from entering the cockpit.
Based on your advice, I went out to the boat today to take a closer look and take additional measurements.
As the most common advice was to move weight forward, I surveyed the possibilities. Currently, the batteries are installed in a compartment on the starboard side about one to two feet forward of the transom. On this dual console configuration, there are compartments port and starboard at the feet of the passenger and helm stations suitable in size for a dual battery installation. There is also a central compartment at the very bow of the boat that two batteries could fit in. Obviously, the most forward option is best for weight distribution, but does the longer cable run (approximately 25’) have negative impacts on the starter and charging systems? If the cable run has minimal negative effects, I will move the batteries to the bow. If a shorter cable run is better, I’ll move them to the amidships position at the base of the helm. Port side at the base of the passenger station would be better for left and right balance, but the helm location is easier because all of the other electrical, steering, and fuel lines run along the starboard side.
Let me know what you all think about the cable run issue.
As moving the batteries forward is the simplest and most inexpensive option, I will try that first and reassess the situation.
Thanks again for the assist and I’ll report back on the results.
Take Care, Slow

SLOWDUK · #8 02-05-2014, 01:17 AM

Thanks to everyone who took the time to comment.
Axespino’s suggestion to close off the motor well in front of the engine is a good one that the previous owner already incorporated. He mounted a piece of starboard about 8” tall with quick release clasps to separate the engine well from the cockpit. It’s not waterproof, but will inhibit a wave that enters the motor well from entering the cockpit.
Based on your advice, I went out to the boat today to take a closer look and take additional measurements.
As the most common advice was to move weight forward, I surveyed the possibilities. Currently, the batteries are installed in a compartment on the starboard side about one to two feet forward of the transom. On this dual console configuration, there are compartments port and starboard at the feet of the passenger and helm stations suitable in size for a dual battery installation. There is also a central compartment at the very bow of the boat that two batteries could fit in. Obviously, the most forward option is best for weight distribution, but does the longer cable run (approximately 25’) have negative impacts on the starter and charging systems? If the cable run has minimal negative effects, I will move the batteries to the bow. If a shorter cable run is better, I’ll move them to the amidships position at the base of the helm. Port side at the base of the passenger station would be better for left and right balance, but the helm location is easier because all of the other electrical, steering, and fuel lines run along the starboard side.
Let me know what you all think about the cable run issue.
As moving the batteries forward is the simplest and most inexpensive option, I will try that first and reassess the situation.
Thanks again for the assist and I’ll report back on the results.
Take Care, Slow

SLOWDUK · #9 02-05-2014, 01:19 AM

test

bradford · #10 02-06-2014, 11:28 AM

Slowduk I moved my batteries to a custom in deck hatch right before the cabin entrance on my cuddy. I used 1 gauge cables. I think putting them a little closer to mid-ship is better in that you don't have SO much dead weight in the bow, they won't get as much of a beating from the waves, and aren't going to get as wet with pulling in wet anchors and rode.