Marschall DE25

To help other builders, please list the boat you are building in the Thread Subject -- and to conserve space, please limit your posting to one thread per boat.

Please feel free to use the gallery to display multiple images of your progress.
kmarschall
Frequent Poster
Frequent Poster
Posts: 11
Joined: Sat Mar 28, 2015 8:16 pm
Location: Clearwater, FL

Re: Marschall DE25

Post by kmarschall »

jacquesmm wrote:OK, I forgot that you were discussing heavy loads.
One of the issues is that once you move up to 150HP they use the same block as the 175 and 200. The weight of the new yamaha 150-200HP in-line 4 cylinder engines is 487lbs. The thought is to move the fuel tanks into the cabin in front of the companionway bulkhead but have them sealed off from the interior of the cabin by building boxes around them to be used as benches. This would shift weight forward as well as clear room in the cockpit. Would moving that 100 gallons of fuel or 600lbs forward offset moving the 487lb engine 18" off the transom? Not having to move the false transom forward to clear the tilt of the engine would create a very nice amount more room in the cockpit as well as make a dive platform off the back of the boat. But if placing the engine there would very much hinder performance we can mount it to the transom. It seems that going from a 115 to a 150-200HP adds about 100lbs. To us, fuel efficiency isn't as important as performance. Many things to think about.

jacquesmm
Site Admin
Site Admin
Posts: 28215
Joined: Wed Aug 14, 2002 1:00 am
Location: Florida USA
Contact:

Re: Marschall DE25

Post by jacquesmm »

I think we discussed that and the conclusion was to move the tank.
The tank is a variable weight and precise calculations don;t make much sense since it's weight will change. To move it as you propose will compensate most of the time and I see no alternatives.
I also remember that we discussed increasing the number of fiberglass layers on the bottom.
A heavier boat needs a stronger bottom.
Jacques Mertens - Designer
http://boatbuildercentral.com

kmarschall
Frequent Poster
Frequent Poster
Posts: 11
Joined: Sat Mar 28, 2015 8:16 pm
Location: Clearwater, FL

Re: Marschall DE25

Post by kmarschall »

jacquesmm wrote:I think we discussed that and the conclusion was to move the tank.
The tank is a variable weight and precise calculations don;t make much sense since it's weight will change. To move it as you propose will compensate most of the time and I see no alternatives.
I also remember that we discussed increasing the number of fiberglass layers on the bottom.
A heavier boat needs a stronger bottom.

At the moment we have 5 sheets of cloth for 3 layers and 2 sheets of tape on the bottom. Should we add more to the outside bottom? If so how much more?

jacquesmm
Site Admin
Site Admin
Posts: 28215
Joined: Wed Aug 14, 2002 1:00 am
Location: Florida USA
Contact:

Re: Marschall DE25

Post by jacquesmm »

It was nice to meet this builder in Homosassa.
Kyle, feel free to post the questions we discussed this week-end.
I remember that I could not answer them all without looking at the plans.
Jacques Mertens - Designer
http://boatbuildercentral.com

David Sours
Frequent Poster
Frequent Poster
Posts: 140
Joined: Fri Nov 21, 2008 2:07 pm

Re: Marschall DE25

Post by David Sours »

Having used my DE 25 for 4 years now, here are my thoughts on the heavier boat, more horse power issue you were discussing earlier. (MHO).
The first time we took our boat, we took another couple for 4 days. None of us are small people and we had all of our camping gear, food, beer (lot of weight!!) etc, etc. I had dropped the fuel capacity to 52 gallons from the designed 80 (?) to save weight. I also eliminated the water tank (40 gals, 320lbs, under the helm seat) in favor carrying on a couple of gallons. I do have ash trim inside, latex foam cushions and seats, teak and holly sole and other "yachty" touches. The boat performed beautifully with the 115 etec.
I think the MOST important concept to grasp is that this boat has NO "hole". It doesn't wallow at 8 - 13 knots like virtually every other boat out there. The transition from displacement to planning speeds is seamless. The boat maintains the same angle and just goes faster as you advance the throttle. I have no trim tabs and would never dream of adding them.
Even with the weight you're talking about, I think a 200 hp would be a mistake. At MOST, I would look for the lightest 140 (Suzuki?) I could find and then prop it for the weight you're talking about. You could put it on a bracket and move water and/or fuel forward to compensate. I think you'd still get 25-30 top end and good acceleration, even with the people and gear you're talking about.
I just think that you might create more problems than you solve by adding weight to this marvelous design. Again, in my humble opinion.--DS

jacquesmm
Site Admin
Site Admin
Posts: 28215
Joined: Wed Aug 14, 2002 1:00 am
Location: Florida USA
Contact:

Re: Marschall DE25

Post by jacquesmm »

Thanks David, I like the "marvelous" design comment.
Seriously, meeting him this week-end, I hope that Kyle understood my reluctance to put too much HP on the boat.
That 115 HP Etec weights 375 lbs. The V6 blocks immediately go above 400 lbs, 420 I think.
Let's stay with 375 lbs or less.
Jacques Mertens - Designer
http://boatbuildercentral.com

David Sours
Frequent Poster
Frequent Poster
Posts: 140
Joined: Fri Nov 21, 2008 2:07 pm

Re: Marschall DE25

Post by David Sours »

Always happy to sing the praises of that design. I'm quite sure that a number of your boats share those wonderful characteristics.
I think a critical piece that some folks miss, is that it is not just putting more weight on the back of the boat, its about putting more weight and placing that weight 3-4 feet BEHIND the transom. With that leverage, it's like putting 600(?) pounds on the transom. I'm sure you can calculate that more accurately, but the point is the same. It's not just how much weight you add, but on a light boat, where you add it. With the load described, if it were me, Id go for the 140 Suzi (or even my 115 etec) propped for the load. There's room for fuel tanks under the galley flat (stbd) and the dinette (port), water under the vee berth. But don't over build it.

TomW1
Very Active Poster
Very Active Poster
Posts: 5844
Joined: Sun Apr 19, 2015 10:57 pm
Location: Bryson City, NC

Re: Marschall DE25

Post by TomW1 »

I agree Jacques and David. An Etec or Yamaha 115 weigh about 375. For a little more HP a Suzuki 140DF weighs 396. After that we are into the 425's and with some companies 480lbs for a 150hp, way to much. I ran Crouch at 4000lbs with a 115 and came up with 30+mph top speed. With the 140 Suzuki he gains 5 mph.

David I believe you are talking center of gravity and you are right. If he puts his motor on a transom bracket set back 2', he will need to add weight in front of the CG in a proportional amount, 2 x 375 = 750lbs. It doesn't have to be added in one place, but it should be stationary and not gas or water. He would probably like a full width transom bracket for his diving.

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

kmarschall
Frequent Poster
Frequent Poster
Posts: 11
Joined: Sat Mar 28, 2015 8:16 pm
Location: Clearwater, FL

Re: Marschall DE25

Post by kmarschall »

Thanks for the replys, guys. It was very informative talking to you this weekend Jacques.

We would love to be able to put a 115 E-TEC on it. Looking at the 25" shaft 115 it weighs 405lbs. We aren't looking for speed but instead the power to hold the boat on the back side of a wave in a following sea with a fair amount of weight onboard. We want to have enough fuel on board to have a range of about 300 miles. If a 115 would be sufficient for this that would be great.

Here are some "worst case" weights.

Fuel - 110 gallons @ 6.3lbs/gal = 693lbs
Fresh water - 20 gallons @ 8.3lbs/gal = 166lbs
Steel Dive Tanks - 8 @ 50lbs = 400 lbs
Dive Gear - about 200 lbs
Anchor and chain - 100lbs
Electronics - 50lbs
Starting Battery - 40lbs
2 deep cycle batteries - 120 lbs
4 people - 720lbs

Total worst case weight without engine - 2489lbs

The bracket would be an 18" setback from the transom.

We talked about removing the dinette and kitchenette because, for our use, they would not be necessary. So the fuel tanks can be moved into that area to free up floorspace in the cockpit.

Also another consideration is the 115HO E-TEC. The same weight as the normal 115 but with an output closer to 130.

Any input would be much appreciated.

User avatar
BarraMan
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 2164
Joined: Tue Dec 11, 2012 3:44 pm
Location: Australia

Re: Marschall DE25

Post by BarraMan »

I'm gonna preface this with, "I know nothing, but .............."! I have owned a few boats and am rapidly moving towards completion of my fantasy boat, which will be either a "weapon" (as one of my mates has described it!) or a "dog", if I have butchered one of Jacques' great designs with my modifications.

For what its worth, my 2 cents worth is that it seems to me that you are asking a lot from this boat. If it were me, I would be looking at a 200 hp Yamaha inline 4 cylinder 4 stroke (488 lb) on a hydraulic jacking plate with some set back (6 - 12") rather than an 18 " setback pod. A moderate setback and the hydraulic lift will overcome the issue of the raising the motor interfering with the transom while reducing the moment arm of the OB. A set of trim tabs wouldn't hurt either!

Given the weight of the boat and the load you wish to carry, I think that boat will be under-powered with 115 hp. Personally, given the distances you want to travel, I would rather have a 200hp motor taking it fairly easy than a 115hp motor screaming its poor little heart out!

But that's just me! What would I know? :lol:

Post Reply

Who is online

Users browsing this forum: Ahrefs [Bot] and 9 guests