Transmission and Aft Engine Access Hatch - Seeking Wisdom on Potential Project

[Dave Spencer]

Starting a new topic instead of reviving a 9 year old thread.  http://c34.org/bbs/index.php/topic,4800.msg28814.html#msg28814
I'm considering adding an access hatch to the forward wall of the aft cabin to improve access to the transmission and other maintenance items that are currently difficult to reach.  I understand that Mk II boats have some improved access in this area but my Mk 1.5 has a solid wall.  I see it as a fairly straight forward job similar to the work Lance Jones did to improve galley sink and faucet access on his Mk I in 2009.  http://c34.org/bbs/index.php/topic,4721.0.html http://www.c34.org/wiki/index.php?title=Sink_Access
However, the aft engine wall appears to be cored vs the relatively thin material Lance had to cut behind his sink.  I'm quite certain the coring is to add mass to the wall to knock down noise and vibration.  Also, several hose supports are screwed to the wall from the engine compartment side.  I can't imagine that the wall is a significant structural member since it isn't really tied into anything that would see a notable load.

The benefits of an access hatch in this location here are pretty clear to me:
#  Improved access to transmission and transmission dipstick making it easier to check and fill transmission fluid.
#  Access to heat exchanger zinc, end caps and heater hose clamps.
#  Access to electric fuel pump and the hidden built in filter in the pump.

I plan to make this an early spring prelaunch project.  I already bought what looks to be a decent gasketed weather deck hatch for $37.  Link here and pictured below.    https://www.amazon.ca/gp/product/B01MDUWHFN/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Has anyone done anything similar to this and do you have any wisdom to share?  For those with Mk II boats, do you have a picture of your rear engine access?  (if it is improved over that on my Mk 1.5)

What say ye?

[jmcdonald]

I have been thinking about doing this too. I wonder if you want a access hatch that opens to the
side, instead of down. I think you may inadvertently lean/put pressure on the hatch when you
reach in though the open hatch, and break it. If you do install the hatch, please report back
if it really improves access a lot or a little.

[Dave Spencer]

Good observation.  Side hinge would be ideal but every I definitely want a hatch that is wider than it is tall and every hatch I saw hinges on the long side.  I agree that hinging on the lower side may result in me leaning on it and damaging it.  Also, I don't have the aft cabin mattress in place in the picture and I don't want to have to remove the mattress to use the hatch.  I think I'll rotate it from what is shown in my pictures and hinge on the top.  I can pull the mattress back a little to allow it to swing up.  If the hatch tends to fall down on me while I'm working, I can secure it up with a bungee cord or something.  Fortunately, the hatch is symmetrical so if I don't like the hinge on the top, I can flip it around and try the hinge on the bottom.

[Roc]

Hi Dave
Interesting that your boat has a hard fiberglass enclosure.  Mine is cabinetry, which I have since placed screws with finish washers on the two sides so I can simply unscrew them and pull the whole wood panel off.  Also pictured is the door I cut into the side to access the pencil zinc.  I believe this door was put into a Mainsheet tech article a number of years back.

[Dave Spencer]

Great pictures Roc.  Thanks, that's exactly the kind of information I was looking for on the Mk II C34s.  You would have excellent access to the back of the engine if you can take the panels right out. 
Very nice work on door to access the heat exchanger zinc.   

[Roc]

Hi Dave
Glad to help...  You might be better off cutting a very large access hatch (way bigger than what you show in your picture), so you have pretty much the same access area as the MkII boats, where the cabinetry can be removed (like I did).  I know you have hoses attached to the back wall of your enclosure.  But the hoses seem to have enough slack that you can just attach them to the horizontal surface (where your hatch is resting) just beyond the wall.  Instead of a pre-made hatch, you can get a large piece of teak, and with 6 screws, 3 at each side, attach it to the hole you saw out.  It would basically look like the MkII enclosure.

[Dave Spencer]

Nice idea Roc.  I'll think carefully about that.  I've checked the hoses and there is certainly enough slack to move them out of the way.  But I fear my cabinetry skills (and patience... the two are related) are not quite up to the standards you've shown on the door that you added.   

[Roc]

Maybe cutting that section and using teak wood for the opening may be a little difficult.  But getting the biggest opening for access should be the goal.  If you can move the hoses, then find out what is the biggest pre-made hatch is available (bigger than you have in your picture), to take up the most of the enclosure.  About cabinetry, Cesar who started his own business when M&H folded, can make a door for you.  He made a formica door for me and the price was not that bad.  His contact Cesar Pacheco Palomera <woodwork@cp-marine.com>
CP Marine Woodwork
17800 S. Main St. , Unit 108 Gardena, CA 90248
Phone:(310)-538-5528 Fax:(310)-538-5364
Web: cp-marine.com

[scgunner]

    Dave,

       If you're going to put an access hatch there, as big as you can make it would be best. If you hinge the port side it will swing away from your work and you won't have to worry about leaning on it. Since you'll be working in a dirty compartment(engine oils, grease, etc.) I think it would be advisable to remove the mattress when working however you decide to do your access hatch.

[Dave Spencer]

Roc,
Thanks for the contact information for CP Marine Woodwork.  I don't think I'm going to go that way though.  The aft cabin is rarely used except as a garage so improving the look of the cabin with custom teak work isn't a priority for me.
Both Kevin and Roc recommended going with as big an opening as possible.  I agree and I've found a much larger hatch that will fit (10" wider than the one I initially picked).  https://www.amazon.ca/dp/B06XW2ZS8Y/?coliid=I19TK7DUVIQCFP&colid=42LRD9564NDC&psc=0&ref_=lv_ov_lig_dp_it  I haven't found a hatch that hinges on the left (the narrow side of the hatch) as Kevin suggested and if I did, I don't think I would go that way since I would have to clear bedding on the mattress and items I stow in the aft cabin to accommodate the large sweep of the hatch as it opens into the cabin.  I'll fit it with the hinge on the top so there is minimal sweep when the hatch is opened and it will be completely out of the way when I'm accessing the rear of the engine.  As Kevin points out, certainly I would remove or protect the mattress if I'm doing any dirty jobs but I don't think that would be necessary for routine inspections like checking the xmsn oil or replacing the HX zinc. 

[Stu Jackson]

Dave, I've often thought about doing this, for the same reasons and with the same genesis of an idea from Lance's work.

But I never thought of buying a hatch, specifically because of the "have to hold it open" issue.

I thought about simply cutting the hole and then adding cleats (wooden slats on each side placed vertically, perhaps routed out or two pieces screwed together) so that I could slide a piece of material into it from top to bottom.  Only complication is the lip from the edge of the teak trim on the top.

No doors, no hinges, no hardware.  It doesn't need to be air tight, I think.  If I found something that caused any engine dirt to get by this loose fitting opening I'd just add some weatherproofing foam to the edges of the sliding material.  The material could be particle board like the stuff under our seats, or even thin plywood.  The lighter the better.

Just another possible approach.

Which I haven't done yet...  I use getting back in and under there as an excuse to clean up Le Garage.  I also haven't seen anyone do it on this forum in my 20 years with Aquavite.  Also, while the side door is nice on the Mark IIs, my HX zinc is on the port side.  I'm still able to service that from the top, 11/16" box end wrench.

Good luck.

[Dave Spencer]

Stu,
I thought a bit about a cleat and board approach but a hatch is relatively inexpensive, readily available and presents a nice clean finish that will hide the sins of my marginal cabinetry skills.  I'm not too concerned about the "have to hold it open" issue.  Given that I don't expect to use the hatch frequently, fitting a bungee cord to hold it open seems reasonable.  The hatch opens 180 degrees so it will be completely out of the way.

My HX zinc is also on the port side so a door like Roc's would look great but wouldn't help with the access I'm looking for.

It seems that this hasn't been done before, or at least it hasn't been documented.  I'll take notes and pictures to be posted and hopefully send what I have to John Nixon for possible inclusion in Mainsheet (although my writing style won't come close to your eloquence in the article published in the last edition about your salon table.  )

[Stu Jackson]

Dave,

Sounds like a good idea.

Sound familiar?!?  :D:D

[rmbrown]

Following 'cause I'm tired of standing on my head...

[Dave Spencer]

I completed this job last spring.  I'm very pleased with the results.  A couple of pictures are attached.  Greatly improved access to the transmission, heat exchanger, hx hoses and zinc, electric fuel pump and the exhaust flange.  Although the hatch folds down, it is not in the way when I'm accessing the rear of the engine.  I wrote this up and it's published in the Spring 2019 Mainsheet for those who are part of the C34IA.