Splashwell or Extended Transom

[Fisherman]

As some of you know, I'm in the process of designing my next offshore boat. I have been planning to make it 22 foot with an additional 2 foot with an extended transom. This extension would be a full continuation of the hull, chine to chine. Not a floatation box or gill bracket. This setup would give me 24' of planning surface.

However, my wife asked me, "why don't you just make it a 24' boat and mount the motor on the transom?" Well, I'm not sure, to be honest, so I'm asking you guys for your input. If I went with this option, I would make the inside of the splashwell the same height as the gunnels.

What advantages or disadvantages are there between my two options? Which would you choose if you were deciding, and why?

[S L Dave]

I find that this is a great design for a 23'. It was custom made by Pacific at the request of the original owner who did not want a bracket. I give up a bit of cockpit space, but I like the "swim"step and I feel that it handles better at idle speeds around the docks compared with similar bracketed 23's that I have driven.

[speedboats]

Doesn't extending the hull plates back 2' then make it a 24' boat anyway? Is not the length of a boat measured from the aft-most section of the bottom plates to the top of where the sides meet at the bow (excluding any overhang, bow-sprit, rails, etc)?

[Fisherman]

It's not a big deal to me (as far as I know) what the legal length is. I just want a boat that runs like I want. Basically, the bottom hull design is the same between my two options. I was advised against a floatation box style of bracket because I will be doing quite a few bar crossings, and others advised that a straight transom would be better than one with many angles.

So now I'm trying to decide how to have the transom designed. I have decided I want the transom to be as tall as the gunnels. So now it is simply trying to decide if there is any advantage to mounting the motor on a bracket?

What about noise, vibration, space, etc....anything I should be thinking about?

If I go with a bracket, how to people attach ice chests? I don't want to have to drill or poke screws into the bracket where water may frequently contact them.

[peterbo3]

You want a full height transom? With access steps both side of the engine? With a transom recess designed to handle the engine when it is tilted but with minimum intrusion into the rear deck area?



This may help..................

[pjay9]

There are many good ideas out there. I think you have some issue that you are concerned about...like following seas on a bar...first running a bar takes some skills and a good boat...the thing is with our fast planing hulls you can stay ahead of the following seas and keep them out of the boat, but to help that along having a full height transom is a very good idea. And to have that with an OB you either have an extension or a OB on a transom with a wall of some sort, like the very handsome one posted above.

When considering length you also need to work in wetted surface area and what it does or doesn't do for you. And there are others on this forum that surely will be able to explain all the physics behind it...but simply more wet =more drag, but if it is done right it will also increase speed...go figure!

Now I am not saying that my boat does it right it is just a solution to the question you pose. Raider extends the hull plate and tapers it in aft of the transom...it gives lift...keeps the water out...allows the motor to sit in a good power utilization position...makes for a good boarding step...allows the kicker to be hung right...more floatation at rest, plus more. Here are some pics!

Hope this gives you some pointers and ideas to consider. BTW, goatram did his own extension and has it posted, plus he indicated that the results helped his boat mucho! Capt PJ

[Fisherman]

A boat builder/salesman told me that a bracket is better than a splashwell for offshore use. While the boat will ride the same, he said the bracket will be safer while drifting because it will allow waves to "break" and loose power instead of having power and enter the boat.

Is there truth to this?

[Chaps]

I like brackets that allow a full height transom but if I was going to do a splashwell I'd probably opt for one like this or Peterbo's

alum mtrwell 1.jpg (177.88 KiB) Viewed 17348 times

alum mtrwell 2.jpg (165.08 KiB) Viewed 17348 times

alum mtrwell 3.jpg (180.16 KiB) Viewed 17348 times

[cgrand]

i'm a big fan of the bulkheaded open transom with splashwell design vs a bracket
it's so much easier to fish from the stern and you get the "real estate" of the splashwell to store/stash wettable items

[Fisherman]

Thanks for all the input. I do want a full-height transom....no question about that.

[dawgaholic]

Pete, answer me a question: I notice the keel flooding holes and figure you've had it both ways, with and without, so is that a design feature that makes the at rest-fishing difference vs. a standard non-ballast monohull?

[JETTYWOLF]

Pete, answer me a question: I notice the keel flooding holes and figure you've had it both ways, with and without, so is that a design feature that makes the at rest-fishing difference vs. a standard non-ballast monohull?

Don't know where that Aussie got off to there Dawg, but I remember we had long discussions about it, and I believe he said something about when having a "deep-v" there's alot of sloshing, and with his "ballast tube" you see a big diff.

PM him and ask...

All I know is I have been on some glass deep-v boats and I mean deep v (true 24.5 degree deadrise) that are only 21 foot and ya can hardly anchor fish because you're tossed from one side to another. Really miserable! But the ride?????
Un believable!

Them super southerners have got it all figgered out, it always seems

[peterbo3]

Pete, answer me a question: I notice the keel flooding holes and figure you've had it both ways, with and without, so is that a design feature that makes the at rest-fishing difference vs. a standard non-ballast monohull?

Hi Dawg,
Deadrise on "Drumbeat" is 23 Degrees so it is not quite the max. Before I had the boat built I went out on a similar hull & four people stood on the stbd gunnel with boat at rest in flat water. It tilted a bit but not alot.
After fishing in the boat for four years, & often going out in other boats without the tubes, I believe I made the right decision. There is still a roll when drifting in snotty 3-4s but ya do not get the neck crackin' SNAP roll that other deep Vs are subject to. Plus you can generally stand up & fish without the need to hang on to a grab rail. Those tubes hold around 600 lb of seawater down low so they are a pretty good counter weight.
They are fitted with breather vents forward so they fill immediately you come to a stop but they empty in a flash once the power is applied.

[West Lake Willows]

Pete,

Is the there a thread that has more pictures of your ballast tubes? I don't want to hijack this thread but I want to see a few more pictures. First time if seen this concept and thinking it's brilliant. My last boat was a seaswirl and they are horrible in a trough. Iknow all to well what a sloppy boat in the trough is like. I love the design concept.

Scott

[peterbo3]

Hi Scott,
Go here:
viewtopic.php?f=6&t=28
Missed the pics showing the tubes being fitted during the build but they run from the transom to where the forefoot starts to curve up. They are fully welded into the hull framing & provide additional strength. There are a few builders who use this design down this way as it really helps to steady the boat at rest on the pick or drifting.

[JETTYWOLF]

Pete, answer me a question: I notice the keel flooding holes and figure you've had it both ways, with and without, so is that a design feature that makes the at rest-fishing difference vs. a standard non-ballast monohull?

Hi Dawg,
Deadrise on "Drumbeat" is 23 Degrees so it is not quite the max. Before I had the boat built I went out on a similar hull & four people stood on the stbd gunnel with boat at rest in flat water. It tilted a bit but not alot.
After fishing in the boat for four years, & often going out in other boats without the tubes, I believe I made the right decision. There is still a roll when drifting in snotty 3-4s but ya do not get the neck crackin' SNAP roll that other deep Vs are subject to. Plus you can generally stand up & fish without the need to hang on to a grab rail. Those tubes hold around 600 lb of seawater down low so they are a pretty good counter weight.
They are fitted with breather vents forward so they fill immediately you come to a stop but they empty in a flash once the power is applied.

Pete,
23 degree deadrise...Not to split hairs but you can call that MAX if ya like (in my book.)
WOW!

[West Lake Willows]

Hi Scott,
Go here:
viewtopic.php?f=6&t=28
Missed the pics showing the tubes being fitted during the build but they run from the transom to where the forefoot starts to curve up. They are fully welded into the hull framing & provide additional strength. There are a few builders who use this design down this way as it really helps to steady the boat at rest on the pick or drifting.

Thank you for the link. I spent almost 2 hours yesterday going through that thread. Very cool and interesting. You wiring job is is amazing.

To get the thread back on track. I have pondered the same question as originally posed, that if you are extending the hull under an offshore bracket, why not just extend the size of the boat. The only rational thought I keep coming back to is the benefit of extending the hull under the transom as this.

1. Increase water contact with the bottom of the hull for ride and to decrease planing speed for fuel economy. In my unprofessional opinion. If you were to extend the transom wall as well and take a 23' boat to a 26' you will get the benefit of a smoother ride, but because you are increasing weight as well the fuel economy will decrease. I think fuel economy increases when the hull increases without proportionally increasing weight.

2. Increase flotation to raise the stern. This is only a benefit if you have a lot of weight on the stern, and again in my opinion if you move the transom wall and redistribute weight directly over the extended hull you lose the added benefit of the flotation directly under the engines but not under the cockpit area.

Again I claim no professional experience and this is a question I have pondered myself. The only other thought I have is cost. A 23' with an extended hull can give you ride closer to a 26' without the expense of stepping up to a larger engine, larger hull, larger trailer etc.

Scott

A

[peterbo3]

Hi Scott,
The pics below show how a full width/depth hull extension was fitted to an earlier alloy CC that I owned to enable a heavier 4 stroke engine to be fitted. The original splash well in the transom is still visible & was retained to allow the new engine to be fully raised.

[spoiled one]

Hey Scott, I extended the bottom of my boat (the width of the extended transom) last season to the back of the extended transom with the hopes of picking up economy and adding some floating for the pair of F250s. My economy improved drastically, it planes out at a slower speed, ride improved, sits level at rest, and I rarely touch the trim tabs. HUGE improvement. I wanted this done when I had the boat built, but met a lot of resistance from the boat builder. I can post before and after pics if you would like.

[welder]

My kind of boat comes already done did that way.

[JETTYWOLF]

Damn, that shiny neked transom needs a "giant" Red decal that says, ALUMINUMALLOYBOATS.COM across it

I know a guy....

He can get you one of our "official logo's" made up. 10-fo?

[West Lake Willows]

I appreciate the info and I added the flotation pod as well under my engine bracket. Very glad I did, as it sits a little lower then I would like now, however, I have twin engines and a heavy kicker so the weight is significant.

I have just pondered advantages vs. disadvantages of the extended hull under the engine bracket vs simply getting a larger boat.

Example.
23' boat with extended hull under the engine bracket so a 26' +/- hull.
vs.
26' boat.

That is what I was doing advantages vs disadvantages for in my unprofessional thoughts in my previous post.

Scott