News:

New Board:  Forum Support (Below Chandlery). Forum Support to submit any questions.

Main Menu
Menu

Show posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Show posts Menu

Messages - P69

#1
This is the current exploded parts diagrams for Kubota engines. You need to know which tractor model your Kubota block was used in, then look up that tractor model in this Illustrated Parts page.

https://shop.kubotausa.com/oemparts/c/kubota_tractor/parts

Attached is a block --> tractor model cross-reference list.
KubotaModel-enginecrossReference.PDF
#2
It's been while since I posted progress, because I have been catching up with completing projects from  extensive delays caused by COVID and Hurricane Sally a few years ago.  I've been working feverishly over the last year to complete my long list (new cabinets, anchor platform, windlass install, hull insulation, re-gel coat all the exterior smooth, new non-skid, ceiling strips, engine box creation and insulation, fire suppression, replumb, rewire, rub rail,  etc....  Here are the details regarding the interior grab bars I installed throughout the boat.

I installed stainless steel grab bars in the overhead throughout the boat in such a way that made the attachment point strong and leak-proof. I searched for months for stainless steel garb bars that could be mounted without through bolts and with mounting plates that are removable, for when I wanted to fasten to a bulkhead where I through bolt. Most of the bars I found had welded-on studs and I needed mounting plates that are removable. Also, most were labeled at 304 SS and I wanted 316 SS.  During those months searching, I also created a way to securely fasten these to the overhead with no through bolts because there would be no corresponding bar or rail on the exterior and I did not want toe-jamming nuts or bolt heads on the outside.  I also wanted to not have any way for water ingress.

I finally found some 316 SS, 12" grab bars that have removable feet. The feet have two M8 (5/16") holes for mounting . If I remove the single, countersunk M8 machine screw that fastens the feet to the grab bar, I can mount them using an M8 machine screw from the other side of the bulkhead. These are 316 SS. The only drawback is that I could find them only in 9" or 12" lengths.  For some areas 24" grab bars would have been nice.  Like most stainless hardware, these are made in China and there is a number of resellers on Amazon that sell these. Pebbly Beach Store is one of about 3 sources I used. 

https://www.amazon.com/Pebbly-Beach-Handrail-Stainless-Handles/dp/B08LK7NCQS?ref_=ast_sto_dp


I usually keep my eye out for price drops and sales, then snatched up a few.  With some of the resellers, I was able to get several dollars off each with a 10 or more purchase.

Design
I mounted the grab bars directly into tapped holes in the overhead. No through bolts to leak, no fastener hardware on the outside catch toes, and no need to line up with exterior grab bars. This last point was important because I spaced the interior grab bars so they are all within one arm's reach.  I can go from the companion way to the forepeak and always have a secure hand hold, whether it is one of these grab bars or one of the two 1 1/4" schedule 40 stainless steel pipes(vertical at nav desk and galley). I also wanted stainless steel for all hand holds because I did not want to inadvertently grab some wood trim or a fiddle that is not as secure as a grab bar.

For mounting the grab bars to the overhead without through bolting, but still having a very secure fastening, I drilled out a 2" diameter circle  through the coach roof, but not penetrating the lower layer of fiberglass (i.e. drilled only through the outer layer and the balsa core).

I marked the locations of were I wanted the grab bars on the overhead, then found the center of the grab bar's mounting plate one each end.  Once all 21 bars marked on the overhead, I drilled a 1/8" hole up through the overhead to the outside.  On deck, I used a 2 1/8" hole saw and, centered on that hole, I drilled out the core, being careful to not drill through the lower layer of fiberglass into the interior liner. I needed to keep that lower layer in place because the grab bar's mounting plates are only about 1" wide x 1.5" long. 

Fiberglass Work
I removed the core to a diameter of about 3", then ground the outer layer of fiberglass to a 12:1 slope.  I used a router with a slot cutter bit.  The balsa core in the coach roof is 3/4" thick and each hole took two passed with the router (first lower pass, then upper pass).


Next, I put tape over the 1/8" hole in the overhead (that interior hole I drilled to mark the exterior) and began laying in circles of 1708 and epoxy until the mass was slightly convex over the exterior.  Each hole took between 15 and 25 layers of material, depending on if I used 1708 or 1700.  To cut the circles, I sandwiched about strips of material between sacrificial strips of 1/2" plywood, then cut out the circles on the bandsaw.  The circle diameters ranged from 3", 2", then up to 5" as I tapered wider near the top of the stack where I ground the 12:1 taper.  There were about 20 or 25 holes in the coach roof that I filled for the grab bars and that was a lot of circles.  Cutting with scissors would have taken a very long time.

Install Grab Bars
After a few days of curing, I ground off the exterior of each patch to be flush with the surrounding  exterior, then faired out with epoxy putty. There were some air bubbles and uneven area.  I let the epoxy cure for about another 2 weeks, then went below to mark each grab bar for drilling and tapping into these epoxy cores.  Each 1/4" flathead machine screw penetrated about 1" up into the epoxy plug.  I used flathead machine screws with sockets for an Allen wrench. These are so much better than Phillips and rarely pop out.

Because the grab bar mounting plates can and do rotate lightly, each grab bar has a unique match to its holes, so they are not interchangeable.  If I had to replace one, I would have to leave the mounting plate a hair loose so it can rotate while I tighten the machine screws into the overhead.  This is not an issue because when the screws tighten, the plates bind slightly between the curved overhead and the actual bar, so they are not lose.

Now, I have strategically-mounted grab bars throughout.  If it's shinny stainless, it's a secure hand hold. No confusion, especially at night or in circumstances that are not ideal.

http://bodylens.com/Gallery/thumbnails.php?album=62

With that out of the way, it's on to the next project. 
#3
Thanks Journey

Attached are pictures of the drilling/cutting templates I made.  I clamped these to the opening and used a router to  cleanup the rough opening and ensure that the openings are the correct dimension.  This template is about 3/8" wider and taller (inside dimensions) than the portlight  to create a gap sufficient to push butyl tape into to seal. 

These are made out of 3/4" plywood and if I were to make new templates, I would double the thickness around each hole with a hardwood block to give a deeper guide for the drill bit. This would ensure a straighter hole that is square to the cabin side.  With just 3/4", I had to eyeball vertical and horizontal.  It was not that much of a big deal because the holes are 3/8 and the machine screws are M6 (~1/4") so there was plenty of room for error.  I think the holes in the window flange are about 13/32, so that is the size I drilled in the template.

#4

Yes, opening ports make a huge difference in ventilation.  Aside from cost savings, I can't thing of any reason to not replace the fixed ports with opening ports (NFM or others).  Because my boat did not have fixed ports, I have no idea if they are stronger than NFM ports, but I suspect the NFM ports would increase the strength watertight of the cabin.

The portlights are made in China and there were months-long delivery issues (summer of 2022) with some of the port lights. Those delays might have resolved by now.  It very likely that they are made at this factory:

https://www.alibaba.com/product-detail/China-supplier-boat-portlight-stainless-steel_60530411246.html?spm=a2700.shop_plgr.41413.18.68dd24b1C8EqG6

https://tuopumetal.en.alibaba.com/search/product?scene=all&spm=a2700.shop_plgr.41413.dsrhbtn&groupId=800455187&SearchText=portlight

The images are the same as what are on NFM website and, if you look really closely, you can see what looks like NFM logo on some of the images from the alibaba site, but it's too blurry to know for sure.  Attached is an enlarged image of that blurry logo and an image from one of the portlights I installed. 
If you are comfortable with buying off of alibaba and can negotiate with their  reps, you might strike a great deal.  Additionally, if NFM goes under or Richard retires, this might be the source for future purchases.

I agree with Ben regarding NFM being a one-man operation, but if the portlights you receive have no issues, it doesn't matter if he quits or dies, your port lights are good.  Anyway, after 30 days, you are out of luck getting any issues resolved by NFM (see their warranty fine-print). See my other post regarding issues I encountered with the hardware and during install. 
https://pearson365.com/forum/index.php?topic=2268.msg11888

Working with Richard at NFM was easy. He knew his products and there were no issues with portlight size or any missing components.  For the most part, the screw lengths he recommended (and supplied), based on my cabin thickness measurements, worked.  I had to swap some out for different lengths because of my highly variable cabin side thickness.
#5

I recently replaced all the portlights (all were opening portlights).  Four were Bomar aluminum and five were plastic Beckson, which were leaking and breaking. The Bomars had severely hazy lenses.  I installed four 6 x 20 and five 5 x 12. The fifth 5 x 12 faces aft from the galley into the cockpit. All were 1 1/2" spigots, except for the 5 x 12 that faces the cockpit, which was a 2" spigot because that cabin side thickness was an inch thick.


There were a few issues with the cabin sides and a few issues with the portlights.

Interior cabinets:
I built a cabinet for over the fridge area and its face frame caused interference with the wood spacer and the dog of the port light which is over the stove. I had to move that opening aft by 1.5".  Check that area carefully if you have an upper cabinet over the fridge to ensure that any new port light will not conflict with the upper cabinet.

Cabin sides:
In all cases, there was a gap between the cabin's fiberglass liner and the exterior cabin side. I filled the gaps with thickened epoxy (cabosil & milled fiber) and, where gaps were large, I epoxied in hardwood shims. Some gaps were barely 1/8" and the maximum was about a skinny 3/4", but most were about 1/2".   This caused issues with the spigot lengths and machine screw lengths.


Wood Spacers:
  • NFM has only one thickness, ~5/8".  With the variable cabin side thickness, this caused some variable spigot stick through on final installation. For example, the two vberth portlight spigots are flush with the trim ring, but most of the rest stick out about 1/2".
  • The color and grain matching within each spacer is not very good.  There is great variation. Fortunately, most of the spacer is covered up by the portlight's interior flange, so it's not noticeable.


Portlight issues:
  • Portlights do not come with screens or machine screws, you must pay extra for them. McMaster is about half the price of what NFM charges and you'll need to get extra of various length machine screws to accommodate your variable cabin side thickness. One can get matching M6 x 1mm truss head machine screws at McMaster Carr: https://www.mcmaster.com/screws/rounded-head-screws/system-of-measurement~metric/rounded-head-style~truss/thread-size~m6/
  • The tapped holes in the trim ring were not tapped completely. I had to use a bottoming tap one each hole and gained nearly 3/16" more threads. Not sure if I needed the extra depth, but during final installation is not the time I wanted to find out.
  • The spigot is not perfectly straight and one of the 6 x 20s had a ding that was rusting.  I suspect that this portlight was smacked with or dropped on a piece of mild steel (the 6 x 20s are really heavy). These portlights are non-magnetic, so they are 316 SS.  This defect does not distort the spigot, it's just a little (1mm x 0.5mm) rusting ding.  If I had noticed that before install, I could have polished it out.  I can still polish it out, but it'll be a bit more cumbersome  on the boat.
  • Before installing, make sure the hinges are tightened.  I'm referring where the hinge fastens to the main part of the port light, not the hinge pin. On the workbench, release the dogs and open the port light.  It should not have any wobble or play in the hinge base. If it does, flip it over and tighten the two fasteners on the backside of the hinges.
  • On one of the 6 x 20 windows the hinge base was loose and I didn't know that I would be unable to tighten once the port light is installed.  Now I have to live with the slight wiggle when I open or close or I have to remove, clean bedding, tighten, then rebed. That's a full day's work.

Trim ring misalignment:
The trim rings are matched to each window (the bolt hole spacing is specific to each window). Even with the "matched" trim rings, I had to slightly enlarge a few of the holes because they were not exactly matched.  The tapped holes in the trim ring are not exactly centered with the holes on the interior flange.  The mismatch was enough to cause the machine screws to press against the hole of the interior flange and bind. Carbide burr on die grinder fixed each in a few seconds. You really need to use a carbide burr in a die grinder because this problem is seen during dry-fit and the die grinder can fix it in seconds without removing the window the countertop/workbench for filing by hand.


Installation issues:
  • You don't need to rent the template, just make your own out of 3/4" plywood (one for each size of window).  Use the port light as the template to mark the  drill holes on the plywood template and to mark the inside cutout.  It is likely that you will run into problems with the template at the forward-most port light openings because those two in the v berth are so close the the deck level. With the plywood template, I just rounded off the inside corners of the template with an angle grinder to loosely fit the curve where the cabin side meets the side deck.  You need some kind of template for drilling and trimming. If you can knock the project quickly, then rent the templates, but if you run into problems and the project drags out for months because of unforeseen issues or weather delays, Richard @ NFM might begin pestering you to return the templates before you finish.
  • TNot a valid attachment ID.Not a valid attachment ID.Not a valid attachment ID.Not a valid attachment ID.    he 5 x 12s  are a little tight for the V Berth. I had to trim the interior teak spacer (see attached picture) to make it fit the upper border with the overhead.  I think Dale installed 4 x 14s.

Lube the threads:
  • Make sure you use Tef-Gel on the threads and the underside of the machine screw heads because it bears against the interior flange when you tighten. Stainless steel galls unpredictably and these threads did not feel smooth at all, even before I retapped the holes.  It would be a real mess if you galled a screw during final install.
  • I followed MaineSail's HowTo for installation of these windows (https://marinehowto.com/installing-newfound-metals-portlights/)
  • I used about 1 and 1/4 rolls of his Bed-It Butyl tape per large window (about 3/4 to 1 roll for the 5 x 12s). There were large gaps to fill.

Cleaning butyl:
After a week of hot weather and daily tightening of the screws, I cleaned off all the butyl squeeze-out. The best tool I found for this task was a demolding  wedge. Like these white/rigid wedges at USComposites. You need something dense, but with just a little flex in it. These are a little denser than Starboard. http://www.shopmaninc.com/demolding_wedges.html
Combination of the wedge and paper towel dampened with paint thinner cleaned off the excess and smoothed it out. Do not use too much paint thinner and wipe it up quickly because it dissolves butyl tape.


Departures from MaineSail and from NFM video instructions:
  • I did not buy NFM's counter bore because Richard identified a problem with his counterbore sticking and gave a solution to spray silicon on it when drilling each hole.  I thought that was a dumb idea to spray silicon in a hole where you'll need to stuff some caulking or butyl tape.  I bought a counterbore from McMaster
  • https://www.mcmaster.com/2919A38/
  • I also did not apply any sealant to the interior of the port lights, not even the dab of silicon to the screw holes that Richard at NFM recommends.  Only the external parts received butyl. 
  • I did not use the foam strips on the perimeter of the trim ring, as Richard  recommends because Bed-It tape does not ooze under high temps.
  • Mainesail's instructions were written prior to Bed-It and he used caulking to seal the exterior. I used only Bed-It


That about covers it. 
More pictures at http://bodylens.com/Gallery/thumbnails.php?album=60

#6
You can try these folks for a replacement.

https://www.mrcool.us/coolers/westerbeke/westerbeke-coolers.html

I bought a replacement heat exchanger from them for my Universal 5444. 
#7
Pearson 365/367 Mechanic Shop / Engine-Exhaust Temps
January 29, 2022, 07:44:32 PM
I got bored and took temperature measurements on different parts of the engine after it had been running, in gear, in the slip for about 45 minutes.

Not sure how this would relate to other engines.



Engine:  Universal Diesel M5444 (Kubota block, V1902)
All temps are degrees F
Measurements taken after 30 minutes running in gear at 2200 rpm
Measurements taken with IR thermometer within 2" of surface

When throttle was increased to WOT, after 1 minute, the highest temp on the dry part of exhaust riser was about 420 degrees on the "First Riser"


Thermostat housing:  167
Aft end of exhaust manifold:  175
Fwd end of exhaust manifold:  200
Exhaust flange:  300
First elbow:  380
First Riser:  400
Second elbow:  330
Horizontal:  300
Down elbow:  300
Raw Water input:  120
Flexible coupling:  100
Waterlift (fiberglass):  100
Exhaust hose after water lift:  110
Exhaust hose half way to transom:  87
Exhaust valve at transom:  85
Exhaust water output at transom:  117
Water temp between Hx and exhaust riser:  80
alternator case (no load):  81
Bottom of crank case:  180
Cylinder Head:  200
Fuel Injector:  120
Temp on Oil Filter fitting:  200
Oil Filter:  190
Water Pump (coolant):  160
Stuffing box:  95
V drive @ oil pump:  105
#8
Pearson 365/367 Yacht Club / Re: Westerbeke Removal
October 02, 2021, 09:26:17 PM
Jim,

I copied Dale's design and it works well.  Attached are rough dimensions.

Here is link to pictures.
Give me a holler if you have any questions.

http://bodylens.com/Gallery/displayimage.php?album=7&pid=474#top_display_media
#9
Pearson 365/367 Yacht Club / Re: Hurricane IDA
September 11, 2021, 10:27:11 PM
Hi y'all,

Yeah, hurricanes are kind of a pain, but at least we get about 3 or 4 days of accurate path predictions now days.  Here is my arrangement that has worked so far.  Essentially, chain goes onshore, line in water directly to cleats, no fairleads/no chafe. 

The shorelines have chains with two round turns on the trees and a chain leader into the water, where it's connected with 5/8 nylon 8-plait. This avoids chafe on the shorelines, which are tied off to cleats mounted on the toe rail, so there is no chafe at all. The anchors have 30' 5/16" chain with 100' 5/8" 3-strand nylon. Each anchor is dug in individually with the motor with the others slacked off, then I take up slack in all lines. Lastly, I cast off whatever length on each line I think I'll need to rise with the water. 

Each of the 10 lines has its own cleat so there is no doubling up on lines.  Stern faces north and most of the strongest winds are from east around to SW. There is little fetch in any wind from SE to NW and not more than 500' fetch to the NE through SE. If a storm passes close to the east and will give strong north or NW winds, then I'll just rotate anchor deployment to the starboard quarter.

The notated colors are spray paint on the ends of line and chain, so I know what goes where, even in the dark (with a normal flashlight, not red colored light).   Attached are pictures that show the chains used for shorelines. With the two round turns, those chains don't slide around the trees (no chafe on trees). The tree loop is 22' long and leaders vary from 15 - 50', depending on the tree's distance from water's edge.

They are all color-coded (shorelines and anchor chain) and chain sections  are stowed in the sectioned bilge during the summer. When we're are in the 3-day cone, I move the boat up a creek to tie it up, then return a few days later.  It's a pain, but I sleep better knowing that it's safer than in a marina with weak dock cleats and wandering boats. I made the mistake with Sally (100 kts wind in local area when it hit) and moved to late when we saw that it turned north straight towards us (24 hours before landfall). Had to move the boat and run all the lines in the dark in 30 - 40 kts wind.  Too rough to dinghy back the 3 miles, so we left the dinghy in the bushes and walked a few miles through the thick, stickery brush, where my sister met us with the car for the drive back to the house.   Y'all down here on the gulf coast know about those weedy vines that have piercing curved spines which tear through light cloth and skin. It sucked, all exposed skin was scratched up from those and the blackberry vines.

Now, whenever we're in the 3-day cone or Tropical Storm winds are predicted because the storm is so large like Ida, I'll move it.  I don't want to walk through the brush again, not knowing where the water moccasins or gators are. Trudging through waste deep grass at 1am in the howling wind and pouring rain is a little disconcerting. At times, the brush was so thick, I had to crawl through the under growth to form a path.

Dale, it's not too bad as long as the boat is prepared and you don't delay.  It's just really hot. Takes about 4 - 6 hours from the time I decide to move until I'm done tied up in the creek and another 4 hours to clean up back at the dock after the storm.  Minimum, I set three shorelines and two anchors, but more if a stronger storm is predicted I set more. I could probably get away with one shoreline and one anchor or just swing to an anchor, but I prefer the redundancy and tucked in close to shore keeps me away from those swinging on an anchor. It's amazing how much protection the trees give and I make sure the boat is far enough from shore so the tallest tree will not hit if it falls. I also point bow to shore (sandy mud with shrubbery) so if the anchors drag, the bow will hit first, not the rudder.   All I have to do is grab the lines and anchors from the shed and shackle to chain, get the dinghy and its motor in the water and I'm ready to go. I don't know what is worse, hurricanes or prolonged deep freeze.





#10
Pearson 365/367 Yacht Club / Re: Air Conditioning
August 24, 2021, 07:25:41 PM
Dale,

I have an older 16000 BTU "Arctic Marine Air" AC/heat pump that does a good job keeping the boat cool in the heat of Gulf Coast summers and taking the chill out of winter time mornings. It's squeezed into the port v berth locker and was installed by a PO. It was a tight fit and all four corners of the opening has to be trimmed square by about 1/2".

There are three outlets:  One in stbd v berth bulkhead (duct ran up, outboard of the drawers), another one, the largest, at the fwd end of the port settee (up high, in line with the upper cabinets), and a small one in the head.  It does a good job cooling the boat, except when small fish get sucked up in the raw water intake and get stuck.

#11
Dale,

Thanks for catching that mistake, "With Mizzen up, CE moves aft, so with mizzen down, you should have more weather helm.:"

I meant to write "less" weather helm with mizzen down.

Regarding the  gap at aft face of the mast, the only reason to rake mast fwd is if the mast is pressing hard against that hole and putting an unfair strain on the mast at that point.

With a roller furling main, the mast should not have any bend; otherwise, rolling the main in and out will become less-than-easy.

As far as weather helm when winds are fresh, I agree that weather helm is designed into the rig/hull, and does not change, but  weather helm is more pronounced in higher winds and greater heel, until you reduce sail, which decreases heel and moves CE slightly fwd.  If one wants to carry full sail longer, but weather helm is too strong, raking the mast fwd might help, as long as there is still slight weather helm at light winds when the hull is not healing. That is the balance I was referring to when stating that Jim needs to strike a balance between too much weather helm at stronger winds and not introducing lee helm in light winds.  If his boat is balance well now, then the only  issue is whether or not the mast is pressing too much against the aft face of the hole in the deck. If so, he can cut the hole a bit to relieve that stress or rake the mast forward, being careful to not introduce lee helm in light winds, because, as you stated, the boat will not round up if too much lee helm.

#12
Jim,

How is the weather helm with full sail and wind strong enough to think, "Hmm should I reef now?"
Same question with the mizzen furled.  With Mizzen up, CE moves aft, so with mizzen down, you should have more weather helm. I have a cutter, so not sure if the mizzen has a noticeable effect on weather helm.

If you have weather helm with 15 - 18 knots, full sail, and lee rail nearly awash, you might rake fwd just a tad to get it mast off the aft face of the hole.  That will give you a bit  of room for wedges  and take any pressure off that contact point.  If raking to give  3/8" or  1/2" at the partner aft face introduces lee helm in light air, you can always take it back to where it was (current position).

Your Hood StoWay furling main has a hollow leech, which already moves the CE forward a little bit.  You could experiment to strike a balance between fwd rake to get mast off partner, reduce weather helm in strong wind (just before you reef) and not introducing lee helm in light winds. Of course, with your furling main, you have infinite reef points.

Attached is a spreadsheet to calculate the rake, based on height and degrees of rake.
If you want a 3/8" gap at the partner, rake the mast fwd 1/4 of a degree.  This will move the masthead (assuming  50' mast) forward by about 2-5/8" (2.62").   This will likely have no noticeable effect on weather/lee helm.  At the spreaders, which is about where center of effort is, the mast will move forward by 1.46 inches (assuming 28 feet to spreaders).

Adjust the numbers (T and A) to get the the gap you want.

In the spreadsheet, the yellow columns use the same formula as the gray  columns to get the value of the unknown, x, which is the horizontal distance (the gap or the masthead).



#13
Kevin,

I have same boat, same engine and a ZF 15M that came with the boat.  Transmission appears to be dated 2004, which is the within a year of the date of the v drive (RV-26).

Attached is pic of the specs plate
A: 1.88, B: 1.95,
Model: ZF 15M


#14
Jordan,

I replaced the four plastic deck thru hulls with a combination of standard bronze thru hull and these TPC-1500 right angle tail pieces

http://www.fawcettboat.com/pc_product_detail.asp?key=77C3F102F5E2459DAE899860319D878A

They are not very good, don't use these.
The primary problem is with the gasket. These fittings use some kind of rubber gasket to seal against the thru hull and when you tighten the nut of the tail piece enough to get good compression on the gasket, it deforms the gasket.  The gaskets that ship with these harden up after a couple of years and leak.  The other problem associated with tightening these is that often the gasket will slip off the mating surface of the thru hull, unless you grind it flat, but that ground surface has to be perfectly flat for the gasket to seal.

I removed the two after deck scupper through hulls (by water heater), sealed up the holes, and cut a channel in the toe rail for water to flow overboard.  I still have these for the two forward  deck thru hulls (by port and stbd settee) and will keep them until I find something better.

The 90 degree angle works out pretty well and one can rotate the tail piece for good alignment, but the design for sealing it is not very good.



#15
The other variable with this concept is that the settee water tanks are likely not integral with the hull.  On my 367, the settee water tanks are actual tanks that were put in and glassed to the hull. If it's the same on the 365s, there is likely to an air space between the hull and the part of tank that presses against the hull. That'll slow the heat transfer quite a bit.