Aluminum Coast Guard Patrol Boat

[Richard Mosena]

I am in the process of re-building an all aluminum Coast Guard Patrol Boat. It is 22.5' long, beam is approx 8', gunnels are a good 12''wide, was foam filled both sides, around engine and has a bulkhead in bow so it would float 6" out of the water if capsized.
Had a Mercruiser (VM) diesel engine 220 hp with a Bravo II outdrive, center console. Weight is approximately 4,750lbs. originally. I have read with interest allot of posts on this forum and would appreciate any help offered in the re-design of my project. A good deal of what I am up against parallels many of the topics you all are discussing. I would be happy to follow through with this group as to the outcome of this project with the interjection of your intellect. Subject matter includes re-foaming, weld repair to hull and possible hull modifications, painting inside and out, re-design of sub floor and interior, adding features, re-power package options, building my own custom trailer. Where to start? And how do I get my pictures up for review.
Sincerely,
Richard Mosena

[FRANKIEFRANKIE]

Will be glad to help. Can put you in touch for power packages and help to get the most out of you hull.

What is the use of your venture and where would you like to be at the end?

I want to end up with a boat that has multiple use. I might go Bay fishing, river running, inland lakes, and hope I could trust it offshore. Hull thickness is 1/4 inch.

So far I have removed everything and cut down to the botton, so the floor and most of the subfloor is all cut out. Some fools had sandblasted inside, I guess to clean around welds so they could plasma cut out the part of the bottom that has been replaced due to corrosion. They missed some bad spots and created more by leaving sand in the boat under the floor to get and stay wet.
Some of the welds look a bit cold, and beads were run outside as well as inside, nothing ground flush. This I can deal with since I am a welder of 30 years, but haven't welded aluminum since my Army days. So I am buying mig and tig rigs as soon as possible and will be getting some tutorial ojt on both. Alcoa 5086 Aluminum was used.

I removed all of the foam and hence left over sand blast sand, am steam cleaning ,chemically treating inside, then after spotless will effect whatever re-welding or metal replacement is necessary in the bottom. I did not like the way the floor was plug welded down and the center console just welded to it. So I have to decide on any interior changes that will be made before proceeding with the sub floor/floor replacement.

The engine is on my engine stand, and it had a good deal of salt water damage; By the time I pay $10k in parts, I am well into a new engine. So I am shopping. Problem here is the engine is a high performance diesel made by "Roger Pensky's company VM
in Italy. Ideally I would like the same engine because I like the tunnel cartel design around the crankshaft. Fortunately, I am a diesel mechanic, and could rebuild a good core. Your Forum has put more questions in my head as to alternatives. Volvo Penta, Yanmar, Steyr (although I am skiddish about an engine with so much aluminum in it and I might prefer the extra weight to keep the boat in the water. Merc's VM engine coupled directly to the outdrive and WOT is 3,800. Got a lot full of Detroits, but they would turn this boat into a troller. I do want it to be perky as it seems it was intended. Extending the transom and going with outboards is tempting for space concerns and redundancy, but this diesel is extremely fuel efficient. This boat only had two 18 gallon fuel tanks.

Perhaps one of the biggest concerns is to make sure the hull which is a modified V will be ok for offshore conditions and to what extent. I plan to add trim tabbs or perhaps make my own. I need the group to look at pictures of the hull and level with me as to the ride conditions, turning ability, planing concerns, and recommendations of any additions or modifications that could be made underneath to improve on its performance and stability.
My goal is not to max out speed, but to have an all round safe boat to go ocean fishing, etc. I might even pull 8 skiers behind it who knows. I am a non-conformist, so with this is mind I want to modernize this boat somewhat to the point of making it interesting and perhaps a bit more comfortable without destroying its original masculine appeal.

I guess it would be best and more concise for the group to tackle one aspect at a time in order of importance. First up would be to review the hull.

[Richard Mosena]

Sorry, That last "Guest" post was mine
Richard Mosena

[Richard Mosena]

Here are some photos (click for a full size view):


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[Tim_Hastie]

Hey Richard
Are You Still Working On That Old Coast Guard Hull> I Was Just Looking Aound And Saw It >>>it Looks Really Familar> Whils With A Company In Canada I Design A Boat That Looks Identical To That For Marinette Marine>
Tim

[gofasts]

I am also building an aluminum boat. Let me know how you make out. What I can tell you it that it is incredibly tough. I had the opportunity to go ripping down rivers in all aluminum jet boats where we literally jumped logs, beaver dams, rocks, everything and the only damage was my bruises.

I will be running an all aluminum high performance 28' boat that should run over 70mph with a 496HO. I have yet to see how this hull will take the waves. I am not worried about structure but comfort of ride..

stay in touch, Kurt

[gray webber]

I am looking for good Aluminum jet boat plans. I am getting ready to build my 4th boat. This one is for life on Lake Superior and small rivers that flow into it. The shore is often roacky and the rivers are shallow. I will not go out in big water but need a nice rider for chop.
I built a whine glass row boat, a kayak, and a 17.5 ft 200hp jet boat all in stich and glue epoxy over wood with system three resins. All are good performers.
The Wood base jet boat is heavy and not suited for rocks. It is a Tracy O'Brien design with 12degree dead rise and 84" beam. I put a 200hp Kodiak jet drive in it. i would like to use this power plant and turn the other hull into an outboad unit. The weekness of the design are as follows: It needs to be 15 to 18degree dead rise for ride comfort and tracking. It needs reverse chine angles to help keep it dryer in high winds. I would like to have a 19ft. boat for general recreation and fishing.

Am I asking too much of a design? I am not interested in high speed as much as good ecconomy.

Does anyone have suggestions--- Other than good luck sucker.
thanks.

[gofasts]

We make aluminum boats, let us get you a hull and then you finish it. We have a 19. If you want pics and prices let me know.

www.triple000ught.com Thanks, kurt

[Frans X L]

Welding over old welds is not a good idea. The metal will lose strength on possibly crack.
Try and get some info from experience alum welders.

The shape of the boat is very blunt with little dead rise. Typically a good seagoing monohull should have a dead rise of say 23 degrees.

The boat looks strong. (If the coastguard could not break it, it should last a while longer)

The boat is a TANB - Trailerable Aids to Navigation Boat.

It is used for servicing small aids (buoys, daymarks) by a local ANT (Aids to Navigation Team), which probably covers a couple of hundred miles of river or port. They are usually co-located with a larger ATON cutter, such as a WLR, WLIC, WLI or WLM.

The Coast Guard has bunches of these, mostly built at SeaArk in Monticello AR.

[stevel]

From the small amout of info that I have been able to dig up, SeaArk and MonArk are either the same company, or had some sort of a close business relationship. From the examples that I have seen, SeaArk builds in Aluminum and MonArk built in glass. I have a 1988 version of the Navy's 26' personnel boat with a 6v53. I haven't been able to find out much about these boats other than some dimensions and weights. It is usually easy to find several for sale on the internet at any given time, but not much else about them. Does anyone know where I could find info on the boats or on MonArk?

[Tim_Hastie]

MetalCraft marine was building some for marinette marine a while back

[CDBarry]

SeaArk is the name chosen by the commercial/military division of MonArk when they sold their recreational boat business to Irwin Jacobs group a few years ago and were unable to continue to use the MonArk brand, which Jacobs then owned. So, prior to the mid-90s both were MonArks made by the same company, afterwards rec boats were MonArks, commercial/military were SeaArks, made by different companies.